COEXPRESSION OF CYCLIN D1 AND RETINOBLASTOMA GENE-PRODUCT (PRB) IN HUMAN SQUAMOUS-CELL LUNG CARCINOMAS IS ASSOCIATED WITH INCREASED TUMOR TAKE RATE IN NUDE-MICE

Samples from 72 squamous cell lung carcinomas were analyzed immunohist ochemically for the expression of cyclin D1 and pRb. Expression of cyc lin D1 was found in 61% and expression of pRb in 39% of the cases. The take rate of human squamous cell lung carcinomas in nude mice was sig nificantly different according to the expression of cyclin D1 and expr ession of pRb in primary human tumors [cyclin D1-negative (32%) vs. cy clin D1-positive (59%); P=0.026; pRb-negative (34%) vs. pRb-positive ( 71%); P=0.002]. The take rate was improved by coexpression of both pro teins [both proteins negative/both proteins positive: 12% vs. 80% (P=0 .00005)]. An association of the take rate and clinical parameters (age , extent of tumors, lymph node involvement, stage) could not be observ ed. Coexpression of cyclin D1 and pRb is also a prognostic factor for the patients' survival.