THE UTILITY OF P53 IMMUNOSTAINING OF TRANSBRONCHIAL BIOPSY SPECIMENS OF LUNG-CANCER - P53 OVEREXPRESSION PREDICTS POOR-PROGNOSIS AND CHEMORESISTANCE IN ADVANCED NONSMALL CELL LUNG-CANCER

There are few reports on the p53 status of small cell lung cancer (SCL C) and advanced non-SCLC (NSCLC) because surgically resected specimens are generally not available. Therefore, we evaluated p53 immunostaini ng in 175 transbronchial biopsy (TBB) specimens obtained from patients with all stages of lung cancer and retrospectively evaluated the rela tionship between p53 status and clinical parameters. All of the specim ens were obtained prior to therapy. Formalin-fixed, paraffin-embedded TBB specimens were immunostained using an anti-p53 antibody (DO-1). p5 3 protein was detected in 55% (61 of 111) of NSCLCs and 58% (37 of 64) of SCLCs. The rate of positivity increased significantly with increas ing stage (stages I and II, 45%; stage III, 54%; stage IV, 66%), but n ot with other clinical parameters. Ninety-five patients were evaluated for their response to chemotherapy. Positive staining for p53 correla ted significantly with unresponsiveness to chemotherapy in NSCLC (resp onse rate of 13 versus 60%; P = 0.006), but not in SCLC (80 versus 57% ; P = 0.22). p53 positivity was a statistically significant negative p rognostic factor for stage III and stage IV NSCLC (P = 0.02), but not for stage I and stage II NSCLC (P = 0.79). There was no survival diffe rence relative to p53 status in SCLC (P = 0.35). These results indicat e that p53 overexpression in TBB specimens predicts poor prognosis and chemoresistance in advanced stage NSCLC.