Interrelationship of prolactin and its receptor in carcinoma of colon and rectum: a preliminary report.

The prolactin receptors (PRLR) were correlated with circulating prolactin and various clinicopathologic parameters to investigate its prognostic value in patients with colorectal cancer. The prolactin (by radioimmunoassay) and its receptors (by radioligand method) were estimated in a total of 71 male patients with colorectal cancer enrolled at the Gujarat Cancer and Research Institute, Ahmedabad. The patients were followed for a period of 3 years. We have observed that 51% colorectal tumors were PRLR+. Significant correlation was not observed between presence/absence of PRLR and clinicopathologic variables. Dukes' D patients were lost to follow-up after 2-3 months; therefore, the results of prognostic significance were analysed only in patients with Dukes' A, B, and C (N = 64). Statistically significant difference in overall survival was not observed when the patients were subgrouped according to the presence/absence of PRLR and according to the cutoff level (i.e., 2%). PRLR+ hyperprolactinemic (Prolactin > 20.0 ng/ml plasma) patients had better overall survival than that of patients with PRLR- hyperprolactinemia, although the difference was statistically nonsignificant. However, PRLR- hyperprolactinemia patients had a more unfavourable prognosis than that of their counterparts. A similar trend was observed in patients with Dukes' B and C disease. Our preliminary study suggests an unequivocal finding, that PRLR- with concomitant hyperprolactinemia probably characterises a subgroup of patients with aggressive colorectal cancer.