Predictive value of expression of p16(INK4A), retinoblastoma and p53 proteins for the prognosis of non-small cell lung cancers

The predictive value of expression of p16(INK4A), retinoblastoma (Rb) and p 53 proteins for prognosis was evaluated in 76 patients with non-small-cell lung cancers (NSCLCs) that were potentially curatively resected between 199 0 and 1995, using the results of immunostaining analyses of these proteins as reported in our previous study (Kinoshita et al, 1996). Of these NSCLCs, 22 (29%) lacked p16 protein expression and eight (11%) Rb protein, while 3 0 (39%) showed positive (altered) p53 protein expression. Survival of patie nts with p16-negative tumours was not significantly different from that of patients with p16-positive tumours (5-year survival rates 67% and 72% respe ctively, P = 0.8), nor was survival of patients with Rb-negative tumours si gnificantly different from that of patients with Rb-positive tumours (5-yea r survival rates 42% and 69% respectively, P = 0.9). Moreover, survival of patients with p16/Rb-negative (either p16- or Rb-negative) tumours was not significantly different from that of patients with p16/Rb-positive (both p1 6- and Rb-positive) tumours (5-year survival rates 67% and 68% respectively , P = 0.7). In contrast, survival of patients with p53-positive (altered) t umours tended to be shorter than that of patients with p53-negative (unalte red) tumours (5-year survival rates 56% and 78% respectively, P = 0.06). In univariate analysis of potential prognostic factors, p16, Rb and p16/Rb pr oteins were not significant prognostic factors in the present cohort of pot entially curatively resected NSCLCs. Altered p53 protein status tended to b e a negative prognostic factor (P = 0.06 by the univariate analysis). These results indicate that loss of p16 protein alone, or in combination with lo ss of Rb protein, does not predict the clinical outcome of patients with re sected NSCLCs. (C) 1999 Cancer Research Campaign.