High Expression of DARPP-32 in Colorectal Cancer Is Associated With Liver Metastases and Predicts Survival for Dukes A and B Patients: Results of a Pilot Study.

The purpose of this study was to investigate prognostic significance of Dopamine and cAMP-Regulated neuronal Phosphoprotein 32 (DARPP-32) expression in primary colorectal cancer. The study material consisted of clinical and histopathological data of 100 patients operated for colorectal cancer between 1994 and 1997. For immunohistochemical analysis, specific rabbit antibodies for DARPP-32 were used and the percentage of stained tumor cells was calculated under gross magnification (400 times) on a sample of 500 tumor cells. DARPP-32 expression in the primary tumor was significantly greater in patients with distant metastases compared to patients with no distant metastases (p=0.002). In multivariate regression analysis, DARPP-32 expression in the primary tumor was a significant predictor of distant metastases. With a cut-off point of 76.5%, DARPP-32 expression in the primary tumor significantly influenced both overall and disease free survival, especially for Dukes A and B patients (p=0.037). The results of this study indicate that DARPP-32 may be a potential marker of worse prognosis and a valuable tool for managing further adjuvant treatment in patients with stages Dukes A and B colorectal cancer.