The expression of mucin-related antigens (Tn, T, Sialosyl-Tn [STn], DF3 [mammary-type apomucin related antigen], and intestinal-MRP [intestinal-type apomucin related antigen]) as well as Ki-67 labeling was examined in 58 mammary invasive ductal carcinomas (IDC) divided into 26 scirrhous subtype (SC) and 32 non-scirrhous subtype comprising papillotubular carcinoma and solid-tubular carcinoma (PT-ST). These data were analyzed in connection with the various pathological prognostic factors such as nodal status, tumor size, estrogen receptor status and histological grading of carcinomas. The results were as follows: (a) in SC, the expression rate of Tn was significantly higher in the cases with positive lymph node metastasis or with large tumor size (> 2 cm) than in those with negative lymph node metastasis or with small tumor size (< or = 2 cm); (b) in PT-ST, the expression rate of STn was higher in the cases with positive lymph node metastasis or with large tumor size than in those with negative lymph node metastasis or with small tumor size; (c) in SC, Ki-67 labeling was significantly higher in the cases with positive lymph node metastasis than in those with negative lymph node metastasis; and (d) in PT-ST, Ki-67 labeling was lower in the cases with positive lymph node metastasis than in those with negative lymph node metastasis. In conclusion, Tn antigen expression was correlated with pathological prognostic factors in SC but not in PT-ST, whereas STn antigen expression was correlated with pathological prognostic factors in PT-ST but not in SC.(ABSTRACT TRUNCATED AT 250 WORDS)