Reduced expression of the cell cycle inhibitor p27Kip1 in non-small cell lung carcinoma: a prognostic factor independent of Ras.

Levels of p27 have been found to have independent prognostic significance in a variety of tumors including breast, colon, prostate, ovary, and gastric carcinomas. We investigated p27 levels and determined ras mutational status in 136 non-small cell lung cancers. We found reduced levels of p27 in 86% of cases and showed a statistically significant inverse correlation between p27 levels and tumor grade. ras mutations were found exclusively in adenocarcinomas and showed no relationship to p27 levels. Clinical data on a subset of the patients studied indicated that all 16 patients who died of disease and 21 of 22 patients who relapsed had low p27 levels, whereas all patients with high p27 levels were alive at last follow up. These findings suggest that alteration in p27 levels plays an important role in lung tumor progression and that p27 levels may have independent prognostic significance in non-small cell lung cancer.