PROGNOSTIC-SIGNIFICANCE OF P53 PROTEIN EXPRESSION AND DNA-PLOIDY IN SURGICALLY TREATED NONSMALL CELL LUNG CARCINOMAS

A series of 112 patients -operated for non-small cell lung cancer was analyzed retrospectively. Nuclear suspensions were prepared from forma lin-fixed, paraffin-embedded biopsies, and DNA content was measured si multaneously with p53 expression using flow cytometry. The expression of p53 protein was determined by the monoclonal antibody PAb 1801, whi ch recognizes both wild-type (normal) and mutated forms of p53. By the level of p53 expression, four patient groups were statistically defin ed. Patients in the two groups with no detectable and extremely high p 53 expression had a significantly better prognosis than patients in th e two groups with moderately increased p53 expression. By logistic reg ression, p53 expression was found to be the single best predictor of 5 year survival. Patient age and tumor stage were less important progno stic factors. No difference in 5 year survival was observed between di ploid and aneuploid tumors. We conclude that p53 is a useful prognosti c predictor in low stage non-small cell lung carcinoma using the monoc lonal antibody PAb 1801. The applicability of this antibody to archiva l material in flow cytometric analysis should allow a broad range of t umor types to be analyzed with respect to the prognostic significance of p53 overexpression.