Histochemical and immunohistochemical study of mucinous rectal carcinoma.

Colorectal cancer (CRC) is a major health problem worldwide. The objective of our study was to assess the histopathological (HP) and immunohistochemical (IHC) profile of mucins from signet ring (SR) and mucinous rectal carcinoma, while evaluating their value as a prognostic factor and muco-secretive ability. The HP study (76 cases) included 4 categories of patients: pure mucinous (PM), mixed mucinous components (MM) (50-80% of the tumor cells), mixed mucinous components (Mm) (< 50% of the tumor cells) and signet ring (SR). The IHC study consisted of a total of 30 cases of MRC and was processed by the ABC/ HRP technique. The antibodies used have addressed their muco-secretive capacity: MUC1, 2 and MUC5AC. MRC cases were more frequent in the sixth decade, with a median age of 57.3 years. It could be noted that MRC tended to develop at younger ages. For the MP variant, the gender ratio was 1.37 in favor of men, while for the MM variant it was 1.16, 1.31 for the Mm and 1.6 in the case of signet ring type. Most of the MRC were moderately differentiated forms, except for the SR form, poorly differentiated forms predominating. Well-differentiated forms were the most underrepresented, being more common in the Mm version. Regarding the biochemical type of mucin, MP and SR were characterized by acid mucins and sialomucin, while in the Mm type, there was a balance of acidic and neutral mucins. The prevalence of mucin acids, respectively sulfomucin, was characteristic to younger ages and poor prognosis.