Cytokeratin 7 and 20 staining for the diagnosis of lung and colorectal adenocarcinoma

Abstract

The origin of metastatic adenocarcinoma lesions can sometimes be difficult to diagnose. The objectives of our study were to establish the cytokeratin staining pattern of primary and metastatic lung and colorectal adenocarcinomas, and to determine if this helps to identify the site of origin of metastatic lesions. We reviewed a total of 102 tissue samples from patients in our tumour registry, with either primary or metastatic lung or colorectal adenocarcinoma. Tissue sections were stained for cytokeratin 7 and 20 and read as positive or negative for staining. Clinical and radiologic information was reviewed from computerised charts. The cytokeratin 7+/cytokeratin 207 pattern characterised 96% (29 out of 30) of primary and 95% (21 out of 22) of metastatic lung adenocarcinomas. All the primary (26), and 88% (21 out of 24) of metastatic colorectal adenocarcinomas stained cytokeratin 77/cytokeratin 20+. Samples from a variety of metastatic sites were evaluated for cytokeratin 7 and 20 staining. Out of the 102 samples, in 95% (97 out of 102) of the cases, the cytokeratin 7 and cytokeratin 20 staining pattern characterised and differentiated between lung and colorectal adenocarcinoma. Primary and metastatic lung adenocarcinomas show a cytokeratin 7+/cytokeratin 207 staining pattern, while colorectal adenocarcinomas stain cytokeratin 77/cytokeratin 20+. Cytokeratin staining is helpful in the diagnostic differentiation of metastatic lesions from these two common primaries, and assists in determining the site of origin of metastatic lesions.

Pulmonary intestinal-type adenocarcinoma does not show enteric differentiation by immunohistochemical study

“…They, and others, have also noted that mucinous bronchioloalveolar adenocarcinoma and signet ring adenocarcinoma of lung fail to express CDX2 with the former showing frequent expression of CK20 but absence of TTF-1. 6,8,19,[27][28][29]31,32 These studies suggest that the expression of enteric markers is related to mucinous differentiation by neoplastic cells particularly goblet cells. Why goblet cell differentiation in goblet cell type colloid carcinoma should have a different phenotype from mucinous variants of bronchio alveolar carcinoma or pulmonary intestinal-type adenocarcinoma is unclear.…”

“…While the morphology of intestinal-type adenocarcinomas resembles colorectal adenocarcinoma, the immunohistochemical profile of TTF-1, CDX-2, cytokeratin 7 and 20, and cytoplasmic mucins clearly demonstrate an absence of enteric differentiation, unlike colorectal and upper respiratory tract sinonasal adenocarcinoma. 14,15,27,28 Historical markers utilized to separate primary lung from metastatic colonic adenocarcinoma are very effective in separating the two neoplasms-pulmonary intestinal-type adenocarcinoma are TTF-1, cytokeratin 7, MUC1 positive, and CDX2, cytokeratin 20, and MUC2 negative, while metastatic colonic adenocarcinoma shows reversed pattern of immunostaining.…”

“…[21][22][23][24][25][26] The expression of or absence of epithelial intermediate filaments CK7 and CK20 are commonly utilized to separate colorectal from other primary adenocarcinomas especially lung. [27][28][29] The six cases of primary pulmonary intestinal-type adenocarcinomas were compared to age-and sex-matched metastatic colonic adenocarcinomas of lung to investigate their staining properties with regard to these antigens and their applicability to the differential diagnosis.…”

Differential diagnostic and functional role of the multi-marker phenotype CDX2/CK20/CK7 in colorectal cancer stratified by mismatch repair status

“…33 CK20 negativity in colorectal cancer has been reported to range between 0 and 9%. 4,11,[51][52][53][54] Park et al 11 observed an association between CK20 loss, higher tumor grade and right-sided location and Hinoi et al 55 observed an association between loss of CDX2, microsatellite instability high status, right-sided tumor location and poor differentiation.…”

Sigmoid colonic metastasis by lymphatic spread occurring with unilateral Krukenberg tumor considered to be caused by stage IA early gastric cancer: A case report

“…Immunohistochemical analyses may be performed to differentiate between gastric and colonic primary tumors, with CK7 and CK20 commonly used as tumor markers (16). CK7 expression has been observed in the majority of types of carcinoma, in carcinoid tumors originating from lungs and gastrointestinal tract (17), and in Merkel cell tumors of the skin (18). CK20 + staining is observed in the vast majority of cases of colorectal carcinoma (17) and Merkel cell tumors (19), in addition to a high proportion of cases of gastric carcinoma, cholangiocarcinoma, pancreatic carcinoma and transitional cell carcinoma (16).…”