MUC1 is upregulated in advanced prostate cancer and is an independent prognostic factor.

Abstract

MUC1 is a membrane-bound glycoprotein that belongs to the mucin family. It is involved in cell adhesion and intracellular signaling. Aberrant expression of MUC1 has been observed in different carcinomas, including prostate cancer, where it may serve as a therapeutic target. There are no data on the prognostic value of MUC1 in metastatic prostate cancer. MUC1 expression was evaluated in tissue microarrays constructed from 119 nodal positive prostate cancer patients treated by radical prostatectomy and extended lymphadenectomy. MUC1 status was correlated with various tumor features and biochemical recurrence-free (bRFS), disease-specific survival (DSS) and overall survival (OS). MUC1 expression was significantly different between primary tumors, lymph node metastases and non-neoplastic glands (scores 53.7 vs 30.1 vs 16.6; P<0.0001). High MUC1 expression in primary tumors was positively correlated with tumor volume (mean 24.4 cm(3) vs 14.5 cm(3); P=0.005) and T-stage (P=0.009); in lymph node metastases, high expression corresponded with a greater total size of metastases (mean 35.8 mm vs 12.7 mm; P<0.001) and a higher ratio of positive to examined lymph nodes (mean 0.22 vs 0.12; P=0.014). High MUC1 expression in lymph node metastases predicted unfavorable outcomes compared with low MUC1 expression (bRFS P=0.023, DSS and OS P⩽0.001), whereas in primary tumors, the same tendency was non-significant. In multivariate analyses, high MUC1 expression in primary tumors and lymph node metastases independently predicted early biochemical failure (P=0.046) and tumor-related death (P=0.0038), respectively. High MUC1 in either primary tumor or lymph node metastases correlates significantly with unfavorable tumor features and survival. Overexpression of MUC1 in the metastases of a subset of prostate cancer patients may have therapeutic potential.