Immunohistochemical study of colorectal adenocarcinomas and adenomas with antibodies against carcinoembryonic antigen (CEA), CA19-9, keratin, alpha-tubulin and secretory component (SC).

The immunohistochemical localization of five antibodies against carcinoembryonic antigen (CEA), CA19-9, keratin, alpha-tubulin and secretory component (SC) was investigated in 14 lesions of adenocarcinoma (AC), 22 of adenoma with high-grade atypia (AH), 50 of adenoma with low-grade atypia (AL), and 15 of non-neoplastic mucosa (NNM) of the large intestine. The positive patterns for each staining were divided into three categories (patterns 1, 2, and 3). All neoplastic lesions (AC, AH and AL) were positive for CEA, while 85.7% of AC, 36.4% of AH and 6.0% of AL showed strongly positive staining (pattern 3). 78.6% of AC and 54.5% of AH were positive for CA19-9 in comparison to 20.0% of AL. For keratin, more than 95% of the neoplastic lesions were positive, while 78.6% of AC, 27.3% of AH and 22.0% of AL showed strongly positive staining (pattern 3). For alpha-tubulin, more than 85% of neoplastic lesions were positive, while 50.0% of AC, 36.3% of AH and 26.0% of AL showed strongly positive staining (pattern 3). For SC, in contrast, 42.9% of AC, 27.3% of AH and 8.0% of AL were negative, but 93.3% of NNM were positive. It was concluded that the positive staining rate, especially the rate of pattern 3 for each antibody correlated with the degree of atypia of the colorectal neoplastic lesions (AC, AH and AL).