Cytokeratin 7 and cytokeratin 20 expression in colorectal adenocarcinomas

Cytokeratin 7 (CK7) and cytokeratin 20 (CK20) are low molecular weight cytokeratins. The expressions of CK7 and CK20 have been studied in various primary and metastatic carcinomas. Their expression patterns may help to distinguish the site of origin of metastatic carcinomas. We investigated the expressions of CK7 and CK20 in 196 cases of colorectal carcinoma. Paraffin sections of 196 colonic adenocarcinomas were randomly selected, retrieved, and immunostained for CK7 and CK20 with a standard avidin-biotin complex method. CK7 was expressed in 34/196 (17.3%) and CK20 in 159/196 (81.1) cases of colorectal adenocarcinoma. CK7−/CK20+ had the greatest proportion (65.8%) in colorectal carcinomas. The CK7+/CK20+ immunophenotype was identified in 30/196 (15.3%), CK7−/CK20− in 33/196 (16.9%), and CK7+/CK20− in 4/196 (2%) colon adenocarcinomas. The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histological grade, location of the tumor, and lymph node metastasis. CK20 positivity was more common in low grade carcinomas than in high grade carcinomas (85.1% versus 47.6%) and in rectal and sigmoid carcinomas than in proximal colon carcinomas (88.2% versus 63.2% and 88.9% versus 63.2%, respectively). Furthermore, CK7 expression was more common in tumors with lymph node metastasis than in non-metastatic tumors (25.3% versus 11%). In conclusion, a considerable number of colorectal carcinomas showed reactivity to CK7 (17.3%) or no reactivity to CK20 (18.9%). Therefore, CK7 positivity or CK20 negativity does not rule out a colorectal origin of metastatic carcinoma.     

Cytokeratin expression patterns of gastric carcinomas according to Lauren and Goseki classification.

The Goseki system is a new gastric carcinoma classification system that classifies gastric carcinomas as grade I (intestinal type), grade II (mucinous type), grade III (mucin-poor, diffuse infiltrating type), and grade IV (signet ring cell type). The main advantage of the Goseki classification may be to separate these distinct entities into different groups. CK7 is not observed in normal gastric mucosa but can be detected in chronically inflamed gastric mucosa and coexists with incomplete intestinal metaplasia. CK20 can be observed in the superficial foveolar epithelium and mature goblet cells. The aim of this study was to examine the cytokeratin expression profiles in gastric carcinomas that are classified according to both the Goseki and Lauren systems. CK7, CK8, CK19, and CK20 were applied to the paraffin sections of 66 gastric carcinoma cases. The cytokeratin expression patterns were grouped as CK20+/CK7+, CK20+/CK7-, CK20-/CK7+, or CK20-/CK7-. The results were examined statistically. CK20 immunoreactivity was observed in 18%, 24%, and 31% of grade I, III, and IV cases, respectively. The CK20+/CK7- pattern was observed in 20% of the grade IV and 66.7% of the grade II carcinomas and was not observed in grade I or grade III tumors (P<0.0001). Goseki grade III and IV carcinomas originate from superficial gastric mucosa, but grade III carcinomas are poorly differentiated. Goseki grade II carcinomas have a specific immunophenotype other than intestinal-type gastric tumors. The Goseki classification seems to be superior in identifying poorly and well-differentiated forms of diffuse infiltrating carcinomas and mucinous carcinomas.     

细胞角蛋白7和20在卵巢转移癌中的表达

目的 观察卵巢转移癌的临床资料、病理形态和免疫组织化学改变,为鉴别卵巢转移癌与原发癌提供依据。方法 对27例卵巢转移癌（其中胃癌12例,结肠癌11例,其他4例）进行了临床和病理形态观察,同时采用免疫组织化学（SP法）对其分别进行细胞角蛋白[CK（AE1/AE3）]、细胞角蛋白7（CK7）、细胞角蛋白20（CK20）、癌胚抗原、波形蛋白、nm23抗原检测。结果 卵巢转移性胃癌12例中11例为双侧实性,卵巢转移性结肠癌11例中7例为单侧囊实性,组织学检查胃癌卵巢转移12例全部以印戒细胞癌或低分化腺癌散在分布为特征,而结肠癌卵巢转移则11例中8例与子宫内膜样癌相似,CK20阳性染色使卵巢转移性胃癌7例及结肠癌8例得到明确诊断,在转移性结肠癌中CK20有稳定的表达,卵巢转移性胃肠道癌中CK7多数阴性,癌胚抗原、波形蛋白、nm23的联合使用使转移性胃癌11例,结肠癌10例得到明确诊断,结论 CK7和CK20在鉴别来自胃肠道的卵巢转移癌中具有重要意义。当几种抗体联合使用时意义更大。     

Cytokeratin expression profile in gastric carcinomas

Cytokeratin (CK) is observed mainly in epithelial cells, and the diverse expression pattern of CK subtypes may be helpful in discriminating between primary and metastatic carcinomas in various organs, including the stomach. To clarify the CK expression profiles in gastric carcinomas, 329 consecutive specimens were immunohistochemically evaluated in terms of their CK subtypes using the tissue array method. The overall positive rates were 84.7% for CK4, 3.2% for CK5, 28.7% for CK6, 71.1% for CK7, 96.6% for CK8, 0% for CK10, 81.6% for CK13, 0.3% for CK14, 4.1% for CK16, 0% for CK17, 99.4% for CK18, 89.7% for CK19, and 30.0% for CK20. Well-differentiated or moderately differentiated carcinomas were related to several CKs, and mucinous carcinoma was associated with CK20 expression. Interestingly, CK7 and CK20 expression was associated with the mucin phenotype of gastric carcinoma, but this association had no diagnostic value. Epstein-Barr virus (EBV)-associated gastric carcinomas showed a tendency toward negative expression of CK7. CK6 expression was related to microsatellite instability (MSI), early pTNM stage, and better clinical outcome. In conclusion, CK expression profiles in consecutive gastric carcinomas demonstrate heterogeneity, and no single CK has diagnostic value by itself. CK expression is associated with various clinicopathologic parameters, mucin phenotype, EBV positivity, MSI status, and patient survival.     

The usefulness of CDX-2 for differentiating primary and metastatic ovarian carcinoma: an immunohistochemical study using a tissue microarray

Distinguishing primary ovarian carcinoma from metastatic carcinoma to the ovary is often difficult by histologic examination alone. Recently an immunohistochemical marker CDX-2 was found to be of considerable diagnostic value in establishing the gastrointestinal origin of metastatic tumors. The aim of this study was to determine whether CDX-2 can distinguish between these malignancies. Paraffin-embedded tissue sections from 57 primary ovarian tumors and 40 metastatic tumors to the ovary were immunostained for CDX-2, and results were compared to the ancillary immunohistochemical results for CK7/CK20, CEA, CA125, and her-2/neu. CDX-2 immunoreactivity was observed in most of metastatic carcinomas with colorectal (91%) and appendiceal (100%) origin, however CDX-2 was negative in all primary ovarian carcinomas, except for the mucinous subtype. Almost all primary ovarian carcinomas including the mucinous subtype showed diffuse and strong immunoexpression for CK7. CEA and CA125 were mainly found in metastatic and primary ovarian carcinoma, respectively. Her-2/neu overexpression was only noted in a small proportion of primary and metastatic ovarian carcinomas. These results suggest that CDX-2 is very useful immunohistochemical marker for distinguishing metastatic colorectal carcinoma to the ovary from primary ovarian carcinoma, including the mucinous subtype. Furthermore, combination with CDX-2 and CK7 strengthen the differential diagnosis between these tumors.     

Expression of cytokeratins 7 and 20 in carcinomas of the gastrointestinal tract

AIMS: The differential expression of cytokeratin (CK) 7 and 20 by carcinomas may help in determining the primary site of a metastatic tumour. The aim of this study was to extend the published data on CK7 and CK20 expression in epithelial neoplasms of the gastrointestinal tract by considering the degree of differentiation and including some unusual neoplasms. METHODS AND RESULTS: Cases referred to the Armed Forces Institute of Pathology were studied prospectively for immunohistochemical expression of CK7 and CK20. Lesions from 105 patients were analysed. Adenocarcinomas of the upper gastrointestinal tract were positive for both CK7 and CK20 in 78% of cases; only poorly differentiated lesions were CK7-. Well-differentiated and moderately differentiated adenocarcinomas of the large intestine, including appendix, were CK7-/CK20+ in the great majority of cases, as were goblet cell carcinoids, but half of the poorly differentiated adenocarcinomas exhibited aberrant expression, as did most of the mixed goblet cell carcinoid/adenocarcinomas. All five high-grade neuroendocrine carcinomas were negative for both CK7 and CK20. CONCLUSIONS: Not only the site but also the grade and histological type of a gastrointestinal carcinoma should be considered when assessing cytokeratin phenotype.     

Differentiation of ovarian mucinous carcinoma and metastatic colorectal adenocarcinoma by immunostaining with beta-catenin

AIMS: To investigate whether localization of beta-catenin is helpful in differentiating primary ovarian mucinous carcinoma and colorectal adenocarcinoma metastatic to the ovary. Extra-ovarian cancers which metastasize to the ovaries, especially from colorectal adenocarcinoma, frequently mimic primary ovarian carcinomas, particularly endometrioid and mucinous types. Distinguishing primary ovarian carcinoma from metastatic colorectal carcinoma is important for both therapeutic and prognostic reasons. Even after thorough histological examination, metastatic colorectal adenocarcinomas are still often mistaken for primary ovarian adenocarcinomas. Although some tumour makers have been advocated and are helpful in most cases, sometimes the distinction between primary mucinous carcinoma and metastatic colorectal carcinoma remains a problem. Activation of Wnt signalling through mutations of APC or beta-catenin is a key event in the development of colorectal cancer. These mutations lead to nuclear localization of beta-catenin, which can be demonstrated immunohistochemically. METHODS AND RESULTS: Formalin-fixed paraffin-embedded specimens from 43 primary ovarian mucinous carcinomas and 23 metastatic colorectal adenocarcinomas were included in this study. Sections were immunostained with antibodies to beta-catenin, cytokeratin (CK)7, CK20 and carcinoembryonic antigen (CEA). Nuclear localization of beta-catenin was found in 83% (19/23) of metastatic colorectal cancers and 9% (4/43) of ovarian mucinous carcinomas. Ovarian mucinous carcinomas were usually positive for CK7 (34/43, 79%). For comparison, 40 non-mucinous carcinomas of the ovary and 42 metastatic adenocarcinomas from other organs were also immunostained with antibodies against beta-catenin. Although nuclear localization of beta-catenin was occasionally seen in non-mucinous carcinoma of the ovary and metastatic adenocarcinoma from other organs, such tumours were usually distinguishable by their clinicopathological picture and rarely raised diagnostic problems. CONCLUSIONS: Immunostaining of beta-catenin is a useful marker for differentiating between ovarian mucinous carcinoma and metastatic colorectal adenocarcinoma.     

CDX-2 immunostaining in primary and secondary ovarian carcinomas

AIMS: To assess the value of homeobox protein CDX-2 expression in the distinction between primary ovarian carcinomas and carcinomas metastatic to the ovary. METHODS: CDX-2 expression was assessed by immunohistochemistry in 120 serous, 68 endometrioid, 24 clear cell, and 16 mucinous carcinomas of the ovary. In addition, CDX-2 immunoreactivity was investigated in 20 metastases from adenocarcinomas to the ovary (15 of colorectal, two of gastric, one of appendiceal, one of pancreatic, and one of cervical origin) and their corresponding primary tumours. RESULTS: Almost all of the primary ovarian carcinomas lacked immunoreactivity for CDX-2. In contrast, 14 of the 16 metastases to the ovary from intestinal primaries showed CDX-2 immunoexpression. CONCLUSION: CDX-2 is a useful marker for differentiating primary ovarian carcinoma from carcinomas metastatic to the ovary.     

An immunohistochemical study of primary signet-ring cell carcinoma of the stomach and colorectum: I. cytokeratin profile in 42 cases

Expression of cytokeratin (CK) profiles in primary signet-ring cell carcinoma (SRCC) of the stomach and colorectum have rarely reported; only two such studies are present in the world literature. Herein, an immunohistochemical study on cytokeratin (CK) expression was performed in 42 cases of primary SRCC of the stomach (30 cases) and colorectum (12 cases). SRCC was defined as an adenocarcinoma in which more than 50% adenocarcinoma cells showed SRCC phenotype with prominent intracytoplasmic mucins. In the gastric SRCC, the expression of CK was as follows; CK AE1/3 (30/30, 100%) CK CAM5.2 (30/30, 100%), CK 34BE12 (0/30, 0%), CK5/6 (2/30, 7%), CK7 (26/30, 89%), CK8 (12/30, 40%), CK14 (0/30, 0%), CK18 (30/30, 100%), CK19 (2/30, 7%), and CK20 (3/30, 10%). In the colorectal SRCC, the expression of CK was as follows; CK AE1/3 (12/12, 100%) CK CAM5.2 (12/12, 100%), CK 34BE12 (0/12, 0%), CK5/6 (0/12, 10%), CK7 (2/12, 17%), CK8 (3/12, 25%), CK14 (0/12, 0%), CK18 (12/12, 100%), CK19 (7/12, 58%), and CK20 (8/12, 67%). A statistical analysis showed that significant differences of CK expression between the gastric SRCC and colorectal SRCC were observed in CK7 (stomach 67% vs. colorectum 17%), CK19 (7% vs. 42%) and CK20 (13% vs. 67%); gastric SRCC tended to express CK7, but not CK19 and CK20, while colorectal SRCC tended to express CK19 and CK20, but not CK7. In gastric SRCC, CK7+/CK20- pattern was as follows: CK7+/CK20- (24/30, 81%), CK7+/CK20+ (2/30, 6%), CK7-/CK20+ (1/30, 3%), and CK7-/CK20- (3/30, 10%). CK7/CK19 patterns in gastric SRCC were as follows; CK7+/CK19- (25/30, 83%) CK7+/CK19+ (1/30, 3%), CK7-/CK19+ (1/30, 3%), CK7-/CK19- (3/30, 10%). In colorectal SRCC, the CK7/CK20 patterns were as follows: CK7+/CK20- (2/12, 17%), CK7+/CK20+ (0/12, 0%), CK7-/CK20+ (8/12, 66%), and CK7-/CK20- (2/12, 17%). The CK7/CK19 pattern in colorectal SRCC was as follows; CK7+/CK19- (1/12, 8%), CK7+/CK19+ (1/12, 8%), CK7-/CK19+ (6/12, 50%), and CK7-/CK19- (4/12, 34%). Statistical data indicated that CK7+/CK20- and CK7+/CK19- patterns were significantly prevalent in gastric SRCC, and CK7-/CK20+, CK7-/CK19+ and CK7-/CK20- patterns dominated significantly in colorectal SRCC. CK expression has been studied largely in terms of CD7/CK20 expression pattern in various carcinomas. The present study provided possible usefulness of CK7/19 expression status in various carcinomas including SRCC.     

Cytokeratin 7 and 20 expression in choroid plexus tumors: utility in differentiating these neoplasms from metastatic carcinomas.

Tumors derived from choroid plexus epithelium are uncommon and may exhibit a wide variety of histologic patterns. They often are difficult to distinguish from metastatic carcinomas. Previous studies that addressed this issue yielded conflicting results. Recent reports have demonstrated that evaluation of coordinate expression of cytokeratin (CK) 7 and CK20 aids in distinguishing primary from metastatic lesions in a number of anatomic sites and that tumors that commonly are metastatic to the brain retain their CK7/CK20 immunophenotype in this location. We examined 35 choroid plexus tumors with a panel of antibodies to determine their CK7/CK20 immunophenotype. Tumors from 35 patients (7 male, 28 female; mean age, 25 years), including 31 choroid plexus papillomas and 4 atypical papillomas, were evaluated. All tumors were intraventricular or within the cerebellopontine angle and composed predominantly of orderly columnar epithelial cells resting on distinct fibrovascular cores. Atypical papillomas contained combinations of focal loss of architectural pattern, increased mitotic activity, necrosis, and brain parenchymal invasion. No lesion was unequivocally malignant. Twenty-six tumors (74%), including all atypical papillomas, were CK7 positive and CK20 negative. Two tumors stained with both markers, one stained with CK20 only, and six stained with neither marker. Other findings included expression of glial fibrillary acidic protein in 24 tumors, S-100 protein in 19 tumors, transthyretin in 31 tumors, Ber EP4 in 1 tumor, CAM5.2 in 33 tumors, epithelial membrane antigen in 4 tumors, and pancytokeratin in 27 tumors. Our results indicate that the majority of choroid plexus tumors have a CK7-positive/CK20-negative immunophenotype. This finding may be useful in differentiating these lesions from metastatic carcinomas that have differing CK7/CK20 profiles.     

Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases.

Cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20) are low molecular weight cytokeratins. Their anatomic distribution is generally restricted to epithelia and their neoplasms. We surveyed 435 epithelial neoplasms from various organ systems by immunohistochemistry using CK 7 and CK 20 monoclonal antibodies. Expression of CK 7 was seen in the majority of cases of carcinoma, with the exception of those carcinomas arising from the colon, prostate, kidney, and thymus; carcinoid tumors of the lung and gastrointestinal tract origin; and Merkel cell tumor of the skin. The majority of cases of squamous cell carcinoma of various origins were negative for CK 7, except cervical squamous cell carcinoma, in which 87% of cases were positive. Approximately two thirds of cases of malignant mesothelioma were CK 7-positive. CK 20 positivity was seen in virtually all cases of colorectal carcinomas and Merkel cell tumors. CK 20-positive staining was also observed in cases of pancreatic carcinomas (62%), gastric carcinoma (50%), cholangiocarcinomas (43%), and transitional cell carcinomas (29%). The expression of CK 20 was virtually absent in carcinomas from other organ systems and in malignant mesothelioma. CK 7- and CK 20-negative epithelial neoplasms included adrenal cortical carcinoma, germ cell tumor, prostate carcinoma, renal cell carcinoma, and hepatocellular carcinoma.     

Cytokeratin profile relates to histological subtypes and intrahepatic location of intrahepatic cholangiocarcinoma and primary sites of metastatic adenocarcinoma of liver

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.     

Utility of cytokeratin 7 and 20 subset analysis as an aid in the identification of primary site of origin of malignancy in cytologic specimens

This study was undertaken to assess the utility of combined cytokeratin (CK) 7/20 immunoprofile determination in malignant cytologic cell blocks as an aid to the identification of tumor primary site of origin. Fifty‐one cases in which CK 7/20 immunocytochemistry was performed as part of the initial workup were retrieved. Their contribution to the final cytologic diagnosis of tumor primary site of origin was analyzed. CK reactivity patterns were 7+/20− (n = 34), 7−/20+ (n = 9), 7−/20− (n = 7), and 7+/20+ (n = 1). The CK 7+/CK 20− immunophenotype was the most common one obtained, and due to its wide expression in a number of common carcinomas, the least informative. The second most common immunophenotype was CK 7−/20+, which is associated with colorectal origin, and as such was very useful when obtained. The CK immunoprofile was more useful in the setting of a prior carcinoma, being a major diagnostic determinant in 13 cases (55%) from group 1 (those with a prior history of malignancy), compared to 8 cases (29%) from group 2 (those with no prior history of malignancy). In the setting of prior carcinoma, the CK immunoprofile is most useful when carcinomas under consideration have different expected immunoprofiles (e.g., CK 7+/CK 20− carcinomas, including lung, breast, ovary, endometrium, and others, vs. CK 7−/CK 20+ carcinomas, primarily colorectal). When similar immunoprofiles are obtained, their usefulness is greater if they are immunoprofiles other than the most common 7+/20− pattern. Similarly, in newly diagnosed carcinomas, the CK immunoprofile either helps to narrow the differential diagnosis or points to a specific diagnosis. Diagn. Cytopathol. 1999;20:63–66. © 1999 Wiley‐Liss, Inc.     

Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder

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.     

Cytokeratin typing as an aid in the differential diagnosis of primary versus metastatic lung carcinomas, and comparison with normal lung

Due to more efficient chemotherapy protocols, the number of second and even third primary carcinomas is steadily increasing. To denominate the possible origin of a carcinoma, different markers are available as an aid, e.g. hormones, proteins and lipoproteins, secretion products and cytoskeletal proteins. Cytokeratins (CKs) have gained new popularity; however, they have not been extensively evaluated in lung tumours. In our study we evaluated the staining patterns of CK polypeptides 4-8, 10, 13, 14, and 17-20 and high molecular weight (HMW) CK polypeptides in routinely processed primary lung carcinomas and lung metastases of diverse origin. As expected, immunohistochemical investigation gave no clear-cut results, but, with statistical analysis, lung adenocarcinomas could be separated from metastatic adenocarcinomas using CK 5 and 18 and HMW CK (specificity 92.5%, sensitivity 62.5%). The different origin of the metastases could often be detected using CK 18 and CK 20. Lung clear cell carcinomas and large cell carcinomas with clear cell areas could be distinguished from metastatic renal clear cell carcinomas by the CK 7 staining reaction. Squamous cell carcinomas of the lung and metastatic squamous cell carcinomas of the larynx, pharynx and oesophagus could not reliably be separated in part due to the few number of cases available. CK polypeptide typing is thus an additional aid in the differential diagnosis of lung carcinomas versus carcinomas metastatic to the lung.     

Cytokeratin 7/20 and mucin expression patterns in oesophageal, cardia and distal gastric adenocarcinomas

AIMS: The current study examined cytokeratin (CK)7 and 20 as well as MUC1-6 immunoprofiles in oesophageal, gastric and gastro-oesophageal junction (GOJ) adenocarcinomas. The aim was to compare expression patterns in these locations as aids to accurate classification of these morphologically similar carcinomas which all may involve the GOJ. METHODS AND RESULTS: Tissue microarrays were constructed using tissue from 14 oesophageal, 78 gastric and 39 GOJ adenocarcinomas. Sections were immunostained with CK7, CK20, MUC1, MUC2, MUC5AC and MUC6. The results of this study showed no differences in CK7 and CK20 expression patterns in the three locations. MUC2 expression was higher proximally (43% of oesophageal, 28% of GOJ and 17% of gastric carcinomas) and MUC6 expression was higher distally (7% of oesophageal, 28% of GOJ and 15% of gastric carcinomas). MUC1 expression was associated with higher pTNM-stage. CONCLUSIONS: CK 7/20 profiles have no role in distinguishing tumours of the three locations. Mucin expression patterns differed in oesophageal and gastric adenocarcinomas, although not sufficiently to classify individual cases. GOJ adenocarcinomas showed a mucin expression pattern that was partly 'gastric', and partly 'oesophageal'. MUC1 expression was associated with a higher pTNM stage.     

Cytokeratins 20 and 7 in the differential diagnosis of metastatic carcinoma in cytologic specimens

A series of 33 tumor cases (13 fine-needle aspirates and 20 effusion specimens) were evaluated for the expression of two cytokeratin (CK) subtypes; CK 20, expressed primarily in tumors of the GI tract, mucinous ovarian tumors and transitional cell carcinomas, and CK 7, found chiefly in non-GI tract adenocarcinomas, including breast and lung. CK 20 expression was demonstrated immunocytochemically in seven of seven metastatic colon and two of three metastatic transitional cell carcinomas tested. CK 20 was absent in all metastatic carcinomas of breast, ovary, lung, and uterus examined (23 cases). Anti-CK 7 stains were negative in four of six metastatic colonic carcinomas, with equivocal results in the remaining two cases. Metastatic lung, breast, and ovarian carcinomas were strongly positive for CK 7. This study demonstrates that the combined use of anti-CK 20 and anti-CK 7 antibodies is highly sensitive and specific for metastatic colonic adenocarcinoma in cytologic material and thus could play an important role in distinguishing this entity from other common primary carcinomas. Diagn. Cytopathol. 16:132–136, 1997. © 1997 Wiley-Liss, Inc.