Significance of CK19 Expression in Detecting Lymph Node Micrometastases in Patients with Colon Carcinoma.

ObjectiverTo evaluate the significance of CK19 expression in diagnosing micrometastases of lymph nodes in patients with colon carcinoma. Methods: Fifty cases of colon carcinoma together with 255 mesenteric lymph nodes were studied, histologic sections of the primary tumor and regional lymph nodes were stained with hematoxylin and eosin (HE) and immunostained with antibody against cytokeratin 19(CK19). Results: In all the cases, CK19 was positively expressed in the primary lesions. Among 255 lymph nodes, metastases were confirmed by HE in 56 lymph nodes(22.0%), and in 76 lymph nodes(29.8%) stained with immunohistochemistry, micrometastases were found in 20 lymph nodes. In the whole series, 12 cases showed lymph node micrometastasis by both staining methods, while another 6 patients showed microme tastases only by immunohistochemistry(21.4%) of 28 patients with negative findings by HE staining. Micrometastasis in the lymph nodes were significantly related to the Dukes' staging. Conclusions: Immunohistochemical staining is a valuable method for the detection of lymph node micrometastases in patients with colon carcinomas. Lymph nodes micrometastasis is significantly correlated with tumor staging.