Background: Cyclin D1 plays a major role as a potential contributor to the multistep process of oncogenesis; nevertheless its prognostic significance in colon cancer has already been examined in a few studies and needs to be further delineated. The aim of this study was to assess the expression of cyclin D1 and pRb and to correlate them with tumor histological stage and grade, proliferative capacity (Ki-67 labeling index) and clinical parameters, in order to delineate their impact on prognosis.
Methods: One hundred and eleven patients, who underwent surgical resection of the colon for colon cancer constituted the group of our study. The immunohistochemical expression of cyclin D1, Rb and Ki-67 proteins was examined and correlated with clinico-pathological parameters and survival.
Results: The 5-years survival rate of patients presenting cyclin D1 positive tumors was 54%, while that of cyclin D1 negative ones was 67% (P = or > 0.05). The survival rate of patients with pRb positive tumors was similar to that of pRb negative ones. Significant association was observed between Ki-67 and cyclin D1 positivity (P = 0.045). Univariate analysis revealed worse survival in advanced stage patients presenting cyclin D1 positive tumors (P = 0.025). Additionally, the survival of patients aging less than 70 years old was correlated to cyclin D1 positivity (P = 0.009). Multivariate survival analysis revealed statistical significance for stage and hepatic metastasis.
Conclusion: Even though cyclin D1 and pRb have not disclosed any clear association with shorter survival, cyclin D1 positivity may be a useful predictor of subgroup patients with colon cancer being in advanced stage and early age.