CARCINOEMBRYONIC ANTIGEN STAINING PATTERNS AT THE INVASIVE TUMOR MARGIN PREDICT THE MALIGNANT POTENTIAL OF COLORECTAL-CARCINOMA

Immunohistochemical carcinoembryonic antigen (CEA) staining patterns a t the invasive tumor margin were correlated with malignant potential i n 64 advanced colorectal carcinomas. Twenty-two (34%) carcinomas showe d an apical and 42 (66%) a cytoplasmic staining pattern. Carcinomas wi th a cytoplasmic pattern had a higher incidence of lymph node (71 vers us 41%; p < 0.05) and liver (50 versus 23%; p < 0.05) metastasis and h igher levels of serum CEA (p < 0.01) than those with an apical stainin g pattern. Nine of 11 recurrent tumors had a cytoplasmic pattern and 2 had an apical pattern (p < 0.05). Among carcinomas having the same de gree of differentiation, those with a cytoplasmic CEA staining pattern were more aggressive. Six (55%) well-differentiated carcinomas with a cytoplasmic pattern metastasized to the liver while none with an apic al pattern did (p < 0.05). Moderately differentiated carcinomas with a cytoplasmic pattern had a significantly higher incidence of lymph nod e metastasis than those with an apical pattern (77 versus 46%; p < 0.0 5). When colorectal carcinomas are examined at the invasive tumor marg in, an evaluation of the CEA staining pattern is useful in recognizing carcinomas having a higher potential to metastasize and recur after c urative surgery.