Proliferating cell nuclear antigen and epidermal growth factor receptor (EGFr) status in renal cell carcinoma patients with polysomy of chromosome 7

We investigated 40 cases of renal cell carcinoma (RCC) to study the polysomy 7 status in papillary and clear-cell types (nonpapillary RCC) and relationship with clinical, pathological, and biological features such as grade, stage, tumor proliferation rate (PCNA expression) and epidermal growth factor receptor (EGFr) expression and thereby to understand the prognostic significance of polysomy 7 and EGFr expression. In a prospective study, chromosome 7 copy number was analyzed in tumor cells by using fluorescence in situ hybridization (FISH) with an α-satellite DNA probe for chromosome 7. Both proliferating cell nuclear antigen (PCNA) and EGFr expression were examined in paraffin sections by immunostaining. The relationship between clinicopathological and clinicobiological parameters was evaluated by appropriate statistical methods. Polysomy 7 was present in 100% of papillary and 56.2% of clear-cell types RCC. In clear-cell RCC, in comparison with polysomy 7-dominant (D) category (20–50% polysomy-7 cells), polysomy 7–major (M) category (>50% polysomy 7 cells) was associated with higher tumor grade (P = 0.05). Polysomy 7 was also correlated with stage of the disease (P = 0.006). The PCNA index ranged between 12.8–89.6% and was comparatively high in high-grade tumors (P = 0.001). The PCNA index was also correlated with polysomy 7 (P = 0.002), and the association was stronger in tumors with polysomy M versus polysomy D category (P = 0.02). The EGFr expression did not correlate with either grade, stage, PCNA, or polysomy 7. The correlation of polysomy 7 with less favorable prognostic factors such as higher tumor grade, stage, and higher proliferative index in the present study indicates that polysomy 7 might be used as a prognostic predictor in clear-cell RCC. Evaluation of clinical end points will confirm the prognostic potential of the genetic marker polysomy 7 in our study.