Expression of sialylated MUC1 in prostate cancer: Relationship to clinical stage and prognosis

Aim: MUC1 is distributed among a variety of normal epithelial tissues, and overexpression of MUC1 is detected in several human cancers. This study aimed to elucidate whether sialylated MUC1 expression correlated with: (i) clinical stage of prostate cancer; (ii) pathological grade of prostate cancer; (iii) pretreatment serum level of prostate-specific antigen (PSA); or (iv) the disease prognosis in patients with prostate cancer who received endocrine therapy. Methods: We collected 57 biopsy specimens from prostate cancer patients treated with only endocrine therapy, and 10 specimens of normal prostates. These specimens were stained immunohistochemically by using a novel monoclonal antibody, MY.1E12, to detect sialylated MUC1. The levels of expression, clinical stages, pathological grades, pretreatment serum level of PSA and the prognoses of the patients were statistically analyzed for correlations. Results: There were statistically significant correlations between the expression of sialylated MUC1 and pathological grades (WHO grade, P < 0.01; Gleason score, P < 0.05). Expression increased according to the progression of the disease (existence of clinical metastasis, P < 0.05; clinical T-stage, P < 0.01). Patients with high serum levels of PSA had higher expression than those with low levels (P < 0.01). The level of sialylated MUC1 significantly correlated with progression-free survival (P < 0.01) and cause-specific survival (P < 0.01) according to univariate analyses. Furthermore, the level significantly correlated with progression-free survival according to multivariate analysis. Conclusions: These results suggest that sialylated MUC1 plays an important role in the progression of prostate cancer, and that its expression level in the primary lesion is a useful marker for the prognoses of patients undergoing endocrine therapy.