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Scheda a cura di Claudio Doglioni e Mattia Barbareschi  (GYM)   

Citocheratine

CK 7 - CK20 

APPLICAZIONI DIAGNOSTICHE 

Hum Pathol 1995 Aug;26(8):852-5

Keratins 7 and 20 as diagnostic markers of carcinomas metastatic to the ovary.
Wauters CC, Smedts F, Gerrits LG, Bosman FT, Ramaekers FC.
Department of Pathology, University of Rotterdam, Dijkzigt Hospital, The Netherlands.
The most common carcinomas metastatic to the ovary that mimic ovarian primaries are colonic adenocarcinomas and endometrial carcinomas. Conventional histochemical staining procedures, even in combination with additional immunohistochemical assays, are of limited value in distinguishing between these metastases and primary ovarian carcinomas. In this study we investigated whether the application of monoclonal antibodies against keratins 7, 8, and 20 could help in differentiating between these categories. The reactivity patterns of 40 carcinomas metastatic to the ovary were compared with those of their primary carcinomas on the one hand and with various primary ovarian carcinomas and mesotheliomas on the other. Colon cancer metastatic to the ovary was keratin 7 negative and keratin 20 positive in 94% of the cases; in contrast, all primary ovarian carcinomas were keratin 7 positive and keratin 20 negative, with the exception of two cases of mucinous cystadenocarcinoma. Ovarian metastases of gastric cancer usually contained keratins 7 and 20. Metastases of endometrial cancer to the ovary and primary ovarian carcinomas usually showed similar keratin expression. We propose that keratin 7 and 20 antibodies may be of help to distinguish between primary ovarian carcinomas and carcinoma metastases in the ovary.

 

Cytokeratins 7 and 20 and carcinoembryonic antigen in ovarian and colonic carcinoma.
Berezowski K, Stastny JF, Kornstein MJ.
Department of Pathology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0662, USA.
The histologic distinction between adenocarcinoma primary to the ovary and metastatic to the ovary can be difficult. In an effort to facilitate this distinction, we have evaluated the use of immunohistochemical techniques with antibodies to cytokeratins 7 and 20, along with antibodies to carcinoembryonic antigen. We studied 24 primary ovarian adenocarcinomas, 11 colonic adenocarcinomas metastatic to the ovary, and 10 primary adenocarcinomas of the colon. Four ovarian adenocarcinomas metastatic to the colon were also studied. All but one of the primary and metastatic colonic carcinomas were negative for cytokeratin 7, whereas all the primary and metastatic ovarian carcinomas were positive for cytokeratin 7. The tumors metastatic to the ovary were all positive for cytokeratin 20 and carcinoembryonic antigen. Among the primary ovarian carcinomas, none of six serous tumors, three of seven endometrioid tumors, and three of 11 mucinous tumors were positive for cytokeratin 20. Ten of the primary ovarian tumors were negative for carcinoembryonic antigen using both monoclonal and polyclonal antibodies. One of the ovarian tumors was negative for carcinoembryonic antigen with the monoclonal antibody but positive using the polyclonal antibody. Cytokeratin 7 is the most helpful marker in the distinction between primary ovarian carcinoma and colonic carcinoma metastatic to the ovary.

Cytokeratin immunostaining in differentiating primary ovarian carcinoma from metastatic colonic adenocarcinoma.
Loy TS, Calaluce RD, Keeney GL.
Department of Pathology, University of Missouri Medical School, Columbia, USA.
The differentiation of ovarian metastases from colonic carcinoma and primary ovarian carcinoma can be difficult. To assess the utility of cytokeratin 7 and cytokeratin 20 immunostains in this setting, we studied routinely processed, formalin-fixed tissue from 165 ovarian tumors, including 45 serous carcinomas, 40 mucinous carcinomas, 64 endometrioid carcinomas, and 16 metastatic colonic adenocarcinomas with an avidin-biotin immunohistochemical technique. A cytokeratin 7+/cytokeratin 20- immunophenotype was seen in 86% of the endometrioid carcinomas, 27% of the mucinous carcinomas, 40% of the serous carcinomas, and none of the metastatic colorectal carcinomas. Conversely, a cytokeratin 7-/cytokeratin 20+ immunophenotype was seen in 94% of the metastatic colonic tumors, 5% of the mucinous carcinomas, and none of the endometrioid or serous tumors. We concluded that cytokeratin immunostains can be helpful in distinguishing metastatic colonic adenocarcinoma from primary ovarian carcinomas, particularly endometrioid carcinomas. Rare ovarian mucinous carcinomas may show the same immunophenotype as metastatic colonic carcinomas.

Ronnett BM, Kurman RJ, Shmookler BM, Sugarbaker PH, Young RH.
Department of Pathology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
Twenty cases of ovarian metastases derived from appendiceal adenocarcinomas were analyzed. The most common presentation was a pelvic mass. The appendiceal and ovarian tumors were diagnosed concurrently in 15 cases; in the remaining five, the ovarian tumors were diagnosed before the appendiceal tumor. The appendiceal adenocarcinomas demonstrated four morphologic patterns: 1) signet ring cell type, with or without glandular or goblet cell differentiation (14 cases); 2) mixed signet ring cell and intestinal type (two cases); 3) intestinal type (two cases); and 4) typical colorectal type (two cases). The ovarian tumors were bilateral in 16 cases and were histologically similar to the associated appendiceal tumor in each case. Ovarian metastases that demonstrate signet ring cell, glandular, and goblet cell differentiation mimic metastases from gastric adenocarcinoma. Those that are derived from well-differentiated mucinous appendiceal adenocarcinomas mimic primary ovarian mucinous tumors and metastases from the pancreas and biliary tract. Metastases of appendiceal adenocarcinomas of colorectal type simulate both metastatic colorectal carcinoma and primary ovarian endometrioid carcinomas. The appendiceal and ovarian tumors were immunophenotypically identical in each case. Approximately 50% of the appendiceal and ovarian tumors were positive for cytokeratin 7 (CK 7), and all were positive for cytokeratin 20 (CK 20). CK 20 positivity of the ovarian tumors is consistent with gastrointestinal origin; CK 7 positivity does not confirm ovarian origin, because appendiceal carcinomas are positive in 50% of cases. Metastatic appendiceal adenocarcinoma should be considered in the differential diagnosis of mucinous ovarian tumors with signet ring cell, goblet cell, or intestinal type differentiation, especially when these tumors are associated with extraovarian disease and are bilateral.

Immunohistochemical differentiation between primary adenocarcinomas of the ovary and ovarian metastases of colonic and breast origin. Comparison between a statistical and an intuitive approach.
Lagendijk JH, Mullink H, van Diest PJ, Meijer GA, Meijer CJ.
Institute for Pathology, Free University Hospital, Amsterdam, The Netherlands.
AIM: To discriminate between adenocarcinomas that are primary to the ovary and metastatic to the ovary, especially of colonic and breast origin, by immunohistochemistry, using stepwise discriminant analysis or a decision tree. METHODS: 312 routinely processed, formalin fixed tissue specimens were used. The tumours were divided into a learning set (n = 159), composed of primary tumours of ovary, breast, and colon, and a test set, comprising 134 metastases from these sites and an additional 19 primary ovarian carcinomas. The immunohistochemical panel was composed of antibodies against cytokeratin 7 (CK7) and 20 (CK20), CA125, vimentin, carcinoembryonic antigen (CEA), gross cystic disease fluid protein-15 (GCDFP-15), and the oestrogen receptor (ER). The staining results of the tumours were expressed as the product of the staining intensity and the percentage of positive tumour cells. Analyses were first performed on the learning set and then evaluated on the test set. RESULTS: Although the immunostaining patterns showed a considerable overlap between the three types of adenocarcinoma, the breast carcinomas were typically positive for GCDFP-15 and often for ER, and negative for vimentin. Ovarian carcinomas were always positive for CK7 and to a lesser extent for CA125. Colonic carcinomas showed prominent positivity for CEA and CK20, while no staining was seen for ER and vimentin. In discriminant analysis, six antibodies (alpha CK7, alpha CK20, alpha CA125, alpha CEA, alpha ER, and alpha GCDFP-15) appeared to be necessary for optimal classification: 89% of the learning set and 82% of the test set were classified correctly. In the decision tree, only four antibodies (alpha CK7, alpha CEA, alpha ER, and alpha GCDFP-15) were used to obtain a correct classification score of 89% for the learning set and 84% for the test set. CONCLUSIONS: Using a semiquantitative assessment of the immunostaining results by a restricted panel of six antibodies with stepwise discriminant analysis, 80-90% of the adenocarcinomas of colon, breast, and ovary can be correctly classified. Discriminant analysis is computer aided and therefore an easy method and for each case a probability value of the classification result is obtained. The intuitive decision tree method provides a slightly better result, requires only four antibodies, and offers a more practical method for the surgical pathologist.

Arch Pathol Lab Med 1999 Oct;123(10):909-1

Comparison of glycoprotein expression between ovarian and colon adenocarcinomas.
Multhaupt HA, Arenas-Elliott CP, Warhol MJ.
Department of Pathology, Pennsylvania Hospital, Philadelphia, PA 19107, USA.
OBJECTIVE: Tumor-associated antigens may be expressed as surface glycoproteins. These molecules undergo qualitative and quantitative modifications during cell differentiation and malignant transformation. During malignant transformation, incomplete glycosylation is common, and certain glycosylation pathways are preferred. These antigens might help distinguish between ovarian and colonic adenocarcinomas in the primary and metastatic lesions. Different cytokeratins have been proposed as relatively organ-specific antigens. DESIGN: We used monoclonal antibodies against T1, Tn, sialosyl-Tn, B72.3, CA125, carcinoembryonic antigen, and cytokeratins 7 and 20 to detect tumor-associated glycoproteins and keratin proteins in ovarian and colonic carcinomas. RESULTS: CA125, carcinoembryonic antigen, and cytokeratins 7 and 20 can distinguish between colonic and serous or endometrioid adenocarcinomas of the ovary in both primary and metastatic lesions. Mucinous ovarian adenocarcinomas differed in that they express carcinoembryonic antigen and cytokeratins 7 and 20 and weakly express CA125. The other glycoprotein antigens were equally expressed by ovarian and colonic adenocarcinomas and therefore were of no use in distinguishing between these 2 entities. CONCLUSION: A panel of monoclonal antibodies against cytokeratins 7 and 20 antigens, CA125, and carcinoembryonic antigen is useful in differentiating serous and endometrioid adenocarcinomas of the ovary from colonic adenocarcinomas. Mucinous ovarian adenocarcinomas cannot be distinguished from colonic adenocarcinomas using immunohistochemistry.

Ovarian metastases from colorectal carcinoma. Clinicopathologic profile, immunophenotype, and karyotype analysis.
Dionigi A, Facco C, Tibiletti MG, Bernasconi B, Riva C, Capella C.
Department of Clinical and Biological Sciences, University of Insubria, Varese, Italy.
Ovarian metastases from colorectal carcinoma frequently mimic primary ovarian carcinomas. The present study was performed to identify possible criteria helpful in differential diagnosis. Twenty-three ovarian metastases from colorectal carcinomas and 23 primary ovarian carcinomas were evaluated clinicopathologically and immunostained with antigastric M1 antigen, cathepsin E, CA125, vimentin, estrogen and progesterone receptors, cytokeratins 7 and 20, and alpha-inhibin antibodies. We performed a conventional and molecular cytogenetic study on 5 ovarian metastases from colorectal carcinoma using direct preparation, Q banding techniques, and fluorescence in situ hybridization. Integration of clinicopathologic, immunohistochemical, and cytogenetic features is helpful for the differential diagnosis of metastases of colorectal carcinomas from primary ovarian carcinomas. Bilaterality, extrapelvic spreading, high mitotic index, and cytokeratin 20 immunoreactivity, and lack of M1, CA125, and cytokeratin 7 immunoreactivity favor the diagnosis of ovarian metastases from colon carcinomas. The identification of 13q gain as a peculiar, sensitive, and specific marker of colorectal carcinomas seems relevant.

Utility of cytokeratin immunostaining in separating pulmonary adenocarcinomas from colonic adenocarcinomas.
Loy TS, Calaluce RD.
Department of Pathology, University of Missouri Medical Center, Columbia 65212.
Adenocarcinomas of uncertain origin are a frequent problem for surgical pathologists. To determine the utility of immunostaining for cytokeratin 7 and cytokeratin 20 in the separation of pulmonary adenocarcinomas from colonic adenocarcinomas, we studied routinely processed, formalin-fixed tissue from 151 of these tumors using commercially available monoclonal antibodies and an avidin-biotin immunohistochemical technique. Used alone, neither cytokeratin 7 immunostaining or cytokeratin 20 immunostaining reliably separated these tumors. However, the immunophenotype of cytokeratin 7 positive/cytokeratin 20 negative was seen in 86% of the pulmonary adenocarcinomas, and in 0% of the colonic adenocarcinomas. Conversely, the cytokeratin 7-negative/cytokeratin 20-positive immunophenotype was seen in 77% of the colonic carcinomas, and in 0% of the pulmonary tumors. In conclusion, cytokeratin 7/cytokeratin 20 immunostaining patterns may be helpful in separating pulmonary adenocarcinomas from colonic adenocarcinomas.

Altri marcatori: TTF-1

Cytokeratin 20 immunoreactivity distinguishes Merkel cell (primary cutaneous neuroendocrine) carcinomas and salivary gland small cell carcinomas from small cell carcinomas of various sites.
Chan JK, Suster S, Wenig BM, Tsang WY, Chan JB, Lau AL.
Department of Pathology, Queen Elizabeth Hospital, Kowloon, Hong Kong.
Cytokeratin 20 (CK20) is a low-molecular-weight cytokeratin (CK) that shows restricted expression in the gastrointestinal epithelium, urothelium, and Merkel cell. Recent studies have suggested that since Merkel cell (primary cutaneous neuroendocrine) carcinomas are consistently CK20-positive, this feature may help to distinguish it from pulmonary small cell carcinomas. However, only limited numbers of these tumors have been studied, and the pattern of CK20 expression in other small cell carcinomas has not been established. Therefore, we studied CK20 expression in small cell carcinomas from a wide variety of sites. Immunohistochemical study was performed on paraffin sections using CK20 antibody, coupled with antigen retrieval by pressure cooking in citrate buffer. The cases included 34 Merkel cell carcinomas and 89 small cell carcinomas from various sites (pulmonary, 37; gastrointestinal tract, nine; pharynx and tongue, two; sinonasal tract, three; salivary gland, five; larynx, nine; breast, two; thymus, three; uterine cervix and corpus, 12, prostate, three; urinary bladder, two; kidney, one; pancreas, one). In addition, all cases were immunostained with pan-CK (MNF-116) and low-molecular-weight CK (CAM5.2) antibodies to ascertain their epithelial nature. With the exception of one case, all Merkel cell carcinomas were CK20-positive; and 30 of the 33 cases showed a punctate pattern. Almost 100% of tumor cells were positive, except for two cases that showed staining of 10% and 30% of tumor cells, respectively. Among the other small cell carcinomas, only five cases were CK20-positive, including one of 37 pulmonary (40% cells positive in punctate pattern), one of 11 cervical (10% cells positive), and three of five salivary gland (100% cells positive). We conclude that CK20-positivity in a small cell carcinoma of uncertain origin strongly predicts a diagnosis of Merkel cell carcinoma, especially if the majority of tumor cells are positive. A negative CK20 reaction can practically rule out Merkel cell carcinoma, provided that an effective antigen retrieval technique is used and appropriate staining is obtained with other cytokeratin antibodies. The frequent CK20 positivity observed in salivary gland small cell carcinomas in this series suggests that at least some of them may be more closely related biologically to Merkel cell carcinoma than to pulmonary-type small cell carcinoma. This may explain why they are far less clinically aggressive than other small cell carcinomas.

Immunostaining for thyroid transcription factor 1 and cytokeratin 20 aids the distinction of small cell carcinoma from Merkel cell carcinoma, but not pulmonary from extrapulmonary small cell carcinomas.
Cheuk W, Kwan MY, Suster S, Chan JK.
Department of Pathology, Queen Elizabeth Hospital, Hong Kong. cheuk_wah@hotmail.com
OBJECTIVE: To study the expression of thyroid transcription factor 1 (TTF-1) and cytokeratin 20 (CK20) in pulmonary small cell carcinomas, extrapulmonary small cell carcinomas, and Merkel cell carcinomas, and thereby determine whether these markers are helpful in distinguishing these 3 groups of small cell neuroendocrine carcinomas. MATERIALS AND METHODS: Immunostaining for TTF-1 and CK20 was performed in 102 cases of small cell carcinoma (pulmonary, 52; extrapulmonary, 50) and 23 cases of Merkel cell carcinoma. The results for the 3 groups were compared. RESULTS: Thyroid transcription factor 1 was expressed in 82.7% of pulmonary small cell carcinomas, 42.0% of extrapulmonary small cell carcinomas (range, 33.3--53.3% for the various sites), and 0% of Merkel cell carcinomas. Cytokeratin 20 staining was consistently negative in pulmonary small cell carcinomas, and positive in 4.0% of extrapulmonary small cell carcinomas and 100% of Merkel cell carcinomas. CONCLUSIONS: Immunostaining for TTF-1, especially when combined with immunostaining for CK20, can aid in the distinction between Merkel cell carcinoma and small cell carcinoma (both pulmonary and extrapulmonary). However, in individual cases, these markers cannot be used to distinguish between pulmonary and extrapulmonary small cell carcinomas due to the extensive overlap in immunophenotypes.

Patterns of distribution of cytokeratins 20 and 7 in special types of invasive breast carcinoma: a study of 123 cases.
Tot T.
Department of Pathology and Clinical Cytology, Central Hospital, Falun, Sweden.
Metastatic adenocarcinomas of unknown primary site are a common clinical problem. Invasive ductal carcinomas of the breast and some special types of invasive breast carcinoma are common sources of metastases. Immunohistochemical algorithms, such as a combination of cytokeratins 20 and 7, can be helpful in this situation. Detailed phenotyping of the different types and subtypes of primary invasive carcinomas and their metastases is an essential prerequisite for a successful search for an unknown primary tumor. A series of 123 primary invasive breast adenocarcinomas of special type and of 27 lymph node metastases was analyzed. Sections of selected blocks were stained with two monoclonal cytokeratin antibodies (CK20 and CK7) and evaluated as negative (no staining), focally positive or diffusely positive. Of the 123 carcinomas, 113 (92%) proved to be CK20 negative. Three of 82 (4%) invasive lobular carcinomas, three of 11 (27%) mucinous carcinomas, one of 10 (10%) tubular carcinomas, and one invasive papillary carcinoma stained diffusely with CK20. Additionally, a tubulolobular carcinoma and a medullary carcinoma showed focal CK20 positivity. One hundred twenty (98%) of the 123 tumors were CK7 positive, five of them only focally. One of the four solid invasive lobular carcinomas, one medually carcinoma, and one invasive papillary carcinoma were completely negative for CK7. Only two cases, one mucinous and one invasive papillary carcinoma, exhibited the CK20(+)/CK7(-) ("colorectal") pattern. One of the lymph node metastases was CK20(+); another was CK7(-). Like their ductal counterparts, invasive breast carcinomas of special type are usually CK20(-)/CK7(+); they generally retain this phenotype in their metastases. However, there are CK20-positive special-type breast carcinomas that can be confused with gastrointestinal or pancreaticobiliary carcinoma in metastases, especially if they are mucinous or invasive lobular.

 

The role of cytokeratins 20 and 7 and estrogen receptor analysis in separation of metastatic lobular carcinoma of the breast and metastatic signet ring cell carcinoma of the gastrointestinal tract.
Tot T.
Department of Pathology and Clinical Cytology, Central Hospital, Falun, Sweden. tibor.tot@ltdalarna.se
Metastatic signet ring cell carcinomas of unknown primary site can represent a clinical problem. Gastrointestinal signet ring cell carcinomas and invasive lobular carcinomas of the breast are the most common sources of these metastases. Immunohistochemical algorithms have been successfully used in the search for the unknown primary adenocarcinomas. In the present study a series of primary invasive lobular breast carcinomas (79 cases) and their metastases and a series of gastrointestinal signet ring cell carcinomas (22 primary and 13 metastases) were stained with monoclonal antibodies for cytokeratin (CK) 20 and CK7 and for estrogen receptors (ER). The staining was evaluated as negative (no staining), focally (less than 10% of the tumor cells stained) or diffusely positive. All the primary and metastatic gastrointestinal signet ring cell carcinomas proved to be CK20 positive, while only 2/79 (3%) of the primary and 1/21 metastatic lobular carcinomas (5%) stained positively for this CK. None of the gastrointestinal carcinomas and the majority of the lobular carcinomas expressed ER. The majority of the tumors were CK7+. Using CK20 alone, 33 of 34 metastases could be properly classified as gastrointestinal (CK20+) or mammary (CK20-). ER identified 31/34 of breast cancer metastases. By combining the results of CK20 and ER staining all the metastases could be properly classified as the CK20+/ER- pattern identified all the gastrointestinal tumors.

 

Thyroid transcription factor-1, thyroglobulin, cytokeratin 7, and cytokeratin 20 in thyroid neoplasms.
Bejarano PA, Nikiforov YE, Swenson ES, Biddinger PW.
Department of Pathology, University of Miami School of Medicine, Florida 33136, USA. pbejaran@med.miami.edu
Thyroid transcription factor-1 (TTF-1), a member of the NKx2 family of homeodomain transcription factors, is a mediator of thyroid-specific transcription of the thyroglobulin (TG) gene. The combined immunohistochemical profile of TTF-1, TG, cytokeratin 7 (CK7), and cytokeratin 20 (CK20) in neoplasms of the thyroid gland and their metastases to other sites has not been defined previously. Formalin-fixed tissue of 43 thyroid tumors, including 31 carcinomas and 12 adenomas, and 16 metastasic lesions were immunostained using monoclonal antibodies to TTF-1, TG, CK7, and CK20. Immunoreactivity of the primary tumors (adenomas and carcinomas) for TTF-1 was seen in 32 cases (74%), TG 32 (74%), and CK7 34 (79%), whereas none (0%) showed positivity for CK20. The distribution of reactivity in the 31 carcinomas for TTF-1, TG, and CK7, respectively was papillary (8/8), (8/8), and (8/8); poorly differentiated (6/7), (4/7), and (6/7); oncocytic (Hurthle) cell (2/6), (6/6), and (4/6); follicular (4/4), (3/4), and (3/4); medullary (1/2), (0/2), and (1/2). One of four anaplastic carcinomas was focally immunoreactive showing positivity for TTF-1 only. Of the six follicular adenomas, five were positive for TTF-1, six for TG, and six for CK7. Among the six oncocytic cell adenomas, five were reactive for TTF-1, five for TG, and all six for CK7. Twelve (75%) of the 16 metastatic tumors were positive for TTF-1, 10 (63%) for TG, 15 (94%) for CK7, and none (0%) for CK20. In summary, TTF-1 and TG are demonstrable by immunohistochemistry in the majority of thyroid neoplasms. Compared with TG, an antibody to TTF-I is a similarly sensitive marker for thyroid tumors. Moreover, TTF-1 is a more sensitive marker for poorly differentiated carcinomas and metastasis. In most cases, its nuclear pattern of immunoreactivity facilitates interpretation. Thyroid tumors are CK7+/CK20-. The panel of antibodies for TG, TTF-1, CK7, and CK20 is useful when the thyroid origin of a metastatic tumor is a consideration.

Cytokeratin 7 and 20 expression in cholangiocarcinomas varies along the biliary tract but still differs from that in colorectal carcinoma metastasis.
Rullier A, Le Bail B, Fawaz R, Blanc JF, Saric J, Bioulac-Sage P.
Service d'Anatomie et Cytologie Pathologiques, Hopital Pellegrin, Universite Victor Segalen, Bordeaux, France.
In the liver, the immunostaining of cytokeratins (CK) 7 and 20 has been used to distinguish usual peripheral cholangiocarcinomas (CC) and colorectal carcinoma metastasis (CRM). However, other subtypes of CC are not infrequent and may be particularly difficult to distinguish from CRM by histology and even immunohistochemistry. Therefore, 48 CC from different locations, either peripheral (n = 19), or nonperipheral, that is, from the large intrahepatic bile ducts, the hilum, and the extrahepatic bile ducts (n = 29), and with different cytoarchitectural patterns were tested for CK7 and CK20 and compared with 31 CRM. CC were positive for CK7 and CK20 in 96% and 70%, respectively, whatever the architecture and differentiation of the tumor. The labeling index (LI) of CK7 in CC was always high, whereas it was low or moderate for CK20. CK20-positive phenotype was significantly more frequent in nonperipheral than in peripheral CC (82% vs 47%; p = 0.007). CRM were all positive for CK20 with a high LI, and mostly negative (81%) for CK7. In conclusion, (1) the CK immunoprofile of CC varies according to the location of the tumor in the biliary tract, peripheral CC being more often CK7+/CK20-, and nonperipheral ones CK7+/CK20+; and (2) a decision tree based on CK20 LI and CK7 positivity allows the distinction of CRM and CC, even for the nonperipheral type.

Cytokeratin profile relates to histological subtypes and intrahepatic location of intrahepatic cholangiocarcinoma and primary sites of metastatic adenocarcinoma of liver.
Shimonishi T, Miyazaki K, Nakanuma Y.
Department of Pathology (II), Kanazawa University School of Medicine, Kanazawa, Department of Surgery, Saga Medical School, Saga, Japan.
AIMS: We evaluated the cytokeratin profile of intrahepatic cholangiocarcinoma with respect to its histological classification and intrahepatic location (peripheral vs. hilar), and compared its profile with that of a variety of metastatic adenocarcinomas in liver. METHODS AND RESULTS: Expression of cytokeratins 7, 8, 18, 19 and 20 was immunohistochemically examined in intrahepatic cholangiocarcinoma (n = 77) and metastatic adenocarcinoma in liver (21 colorectal, 14 gastric, three gallbladder and three pancreatic cancers). Materials were autopsy or surgical specimens. Cytokeratins 7, 8, 18 and 19 were expressed in 75 (97%), 75 (97%), 59 (77%) and 71 (92%) cases of intrahepatic cholangiocarcinoma, respectively. Moderate and extensive expression of cytokeratin 18 was more frequent in the peripheral than in the hilar type. Moderate and extensive expression of cytokeratin 19 was seen in almost all cases of well-differentiated intrahepatic cholangiocarcinomas, while expression was decreased relatively in the moderately and decreased more in the poorly differentiated cases. While cytokeratin 20 was not found in non-neoplastic biliary epithelia or in well-differentiated intrahepatic cholangiocarcinomas, this cytokeratin was occasionally detectable in moderately and poorly differentiated intrahepatic cholangiocarcinomas and its expression was more frequent in the hilar type. Cytokeratin 20 expression was observed in 17 (81%) of metastatic adenocarcinomas in liver from colorectal regions, to a lesser degree in those from gastric regions, and was rare in those from gallbladder and pancreatic regions; cytokeratin 7 showed a reverse expression pattern in these metastatic adenocarcinomas in liver. The profile of cytokeratins 7 and 20 of metastatic colorectal and gastric carcinomas differed from that for intrahepatic cholangiocarcinomas, while that of metastatic gallbladder and pancreatic carcinoma was similar to that for intrahepatic cholangiocarcinomas. Moreover, cytokeratin 18 and 19 expression was significantly infrequent in metastatic gastric carcinomas than in intrahepatic cholangiocarcinomas and metastatic colorectal carcinomas. CONCLUSION: The combined immunostaining of cytokeratins 7, 18, 19 and 20 is useful for the characterization of intrahepatic cholangiocarcinomas with respect to histological subtypes and intrahepatic location. It helps to differentiate intrahepatic cholangiocarcinoma from metastatic adenocarcinomas in liver and from colorectal and gastric regions; it also indicates the primary focus metastatic adenocarcinomas in livers.

Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder.
Duval JV, Savas L, Banner BF.
Department of Pathology, UMass Memorial Health Care, Worcester, MA 01655, USA.
BACKGROUND: Expression of cytokeratins 7 (CK7) and 20 (CK20) may help distinguish the site of origin for metastatic carcinomas. Little is known regarding their expression in biliary tract and pancreatic carcinomas. Our aim was to study the expression of CK7 and CK20 in these tumors. DESIGN: Fifty-three carcinomas of the extrahepatic bile ducts (n = 8), ampulla of Vater (n = 7), gallbladder (n = 11), and pancreas (n = 27), were retrieved from the surgical pathology files of the University of Massachusetts Medical Center. Formalin-fixed, paraffin-embedded sections were immunostained with mouse monoclonal antibodies to CK7 and CK20 using an avidin-biotin immunoperoxidase technique with microwave antigen retrieval. The percentage of cells positive for each antibody was assessed on a scale of 0 to 3 (0, ˜10%; 1+, 10% to 50%; 2+, 51% to 90%; 3+, >90%). RESULTS: The majority of carcinomas in all groups were positive for CK7 (CK7+) and negative for CK20 (CK20-). Of the CK7+ tumors, the majority of tumors in each group were 3+ positive. CONCLUSIONS: (1) Carcinomas of the extrahepatic biliary tract and pancreas are strongly positive for CK7 and negative for CK20 and can be included in the differential diagnosis of other carcinomas with this profile in metastatic sites. (2) The CK7/CK20 immunostaining profile will not identify the site of origin for tumors with extensive growth in the porta hepatis region.

Adenocarcinomas metastatic to the liver: the value of cytokeratins 20 and 7 in the search for unknown primary tumors.
Tot T.
Department of Pathology and Clinical Cytology, Central Hospital, Falun, Sweden.
BACKGROUND: Metastatic adenocarcinoma in the liver with an unidentified primary tumor site is a common clinical problem. Pathologists often are asked to identify the primary tumor site. The histologic picture itself usually is not helpful, because the histology may be similar in the metastases of tumors with different primary localizations. Immunohistochemistry can be helpful, but the previously recommended antibody panels are too complicated for everyday use. METHODS: A simple immunohistochemical algorithm with two monoclonal cytokeratin (CK) antibodies, CK20 and CK7, was tested on 93 autopsy cases of adenocarcinomas metastatic to the liver. Sections of the liver metastases were stained automatically and evaluated as negative (no staining), focally positive, or diffusely positive. Statistical comparison of the staining results for a single antibody was calculated as an odds ratio. RESULTS: Thirty-six of 93 (39%) metastases proved to be CK20 positive (+). In this group, the CK20+/CK7 negative (-) pattern was highly characteristic for colorectal localization of the primary tumor, having been observed 17 of 21 of the cases (81%). The CK20+/CK7+ pattern of the metastatic liver adenocarcinomas was highly suggestive of primary localization in the pancreas or biliary tract (11 of 14 cases; 79%). Exclusion of the tumors originating in the stomach raised these values to 94% and 92%, respectively. The statistically calculated predicted probability of primary tumor site being in the colon or rectum for CK20+/CK7- metastasis was 78,41%, the probability of a primary tumor being located in the pancreas or biliary tract was 74,85%, if calculated for the whole study group. CONCLUSIONS: The tested simple algorithm proved to be useful in CK20 positive (+) cases, predicting a primary tumor localization in the colon, rectum, pancreas, or biliary tract with high accuracy. The CK20- group was too heterogeneous to be classified adequately by these two antibodies.

Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma.
Bassily NH, Vallorosi CJ, Akdas G, Montie JE, Rubin MA.
Department of Pathology, University of Michigan, Ann Arbor 48109-0054, USA.
We studied the expression of cytokeratin (CK)-7 and CK-20 in prostate adenocarcinoma and urothelial carcinoma and evaluated their usefulness for distinguishing high-grade forms of these tumors. We examined prostate adenocarcinoma in 59 radical prostatectomy specimens and in 10 autopsy specimens showing metastatic disease, and urothelial carcinoma of the bladder in 28 cystectomy specimens. Immunohistochemical staining for CK-7, CK-20, and prostate-specific antigen (PSA) was performed on paraffin sections. For prostate adenocarcinoma, 5 cases had only CK-7 positivity, 5 had only CK-20 focal positivity, 1 stained for both markers, and 48 were negative for both. PSA was positive in all but 1 poorly differentiated prostatic carcinoma. In the autopsy cases, PSA was expressed in the prostate and the metastatic tumors in most cases; few cases were focally positive for CK-7 or CK-20, but none was positive for both markers. For the urothelial tumors, CK-7 was the sole positive marker in 6 cases, and CK-20 in 1 case; 17 cases were positive for both, and 4 were negative for both. All urothelial carcinomas were PSA negative. Although PSA is useful for differentiating prostatic from urothelial carcinoma, CK-7 and CK-20 are helpful when both are positive, supporting the diagnosis of urothelial carcinoma. However, if only 1 marker is positive or both are negative, these markers have limited usefulness for distinguishing these carcinomas.

Rene: carcinoma cromofobo vs. oncocitoma

Altri marcatori: Parvalbumin

Utility of cytokeratin 7 for distinguishing chromophobe renal cell carcinoma from renal oncocytoma.
Leroy X, Moukassa D, Copin MC, Saint F, Mazeman E, Gosselin B.
Department of Pathology, CHRU, Lille, France. bgosselin@chru-lille.fr
OBJECTIVE: Chromophobe renal cell carcinoma is a relatively uncommon variant of renal carcinoma described in 1985. The main differential diagnosis is renal oncocytoma. Hale's colloidal iron staining is a powerful adjunct to morphological interpretation but it is not specific and is sometimes difficult to interpret. We studied the immunohistochemical expression of cytokeratin 7 to determine its value in distinguishing chromophobe renal cell carcinoma from renal oncocytoma. METHODS: Immunostaining was performed on paraffin-embedded tumor tissue of 6 chromophobe renal cell carcinomas and 11 oncocytomas with an antibody to cytokeratin 7 (clone OV-TL 12/30, Dako, France) using a streptavidin-biotin method. RESULTS: All chromophobe renal cell carcinomas showed strong cytoplasmic staining with peripheral cell accentuation. In contrast, 8 of 11 oncocytomas were entirely negative and 3 showed only weak and focal staining in less than 5% of the tumor cells. CONCLUSION: Immunohistochemical staining for cytokeratin 7 may be useful for the differential diagnosis of renal oncocytomas and chromophobe renal cell carcinomas when Hale's colloidal iron staining is uncertain.

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