Abstract

An immunohistochemical stain for the Rb tumor suppressor gene product was performed in pathologic specimens from 72 primary lung cancer patients to study the correlation between its expression and histologic type, cancer differentiation, clinical stage and survival rate. The expression of the Rb protein was positive in 34 cases(47.2%) and negative in 38 cases(52.8%). The Rb protein was not expressed in 16 of 42 cases(38.1%) in squamous cell carcinoma, in 17 of 23 cases(73.9%) in adenocarcinoma, in one of three cases(33.3%) in undifferentiated large cell carcinoma, in two of two cases(100%) in small cell carcinoma, in one of one case(100%) in an adenosquamous carcinoma and in one of one case(100%) in an atypical carcinoid. There were significant difference of the Rb protein expression between squamous cell carcinoma and adenocarcinoma(p<0.05). The expression of Rb protein was not correlated with degree of cancer cell differentiation and clinical stage of the lung cancer(p>0.05). The two year survival rate for patients with the Rb positive was 65% compared with 37% for those with the Rb negative which was significant(p<0.05). This result suggests that an altered or the absence of the Rb protein in cancer cells can be a valuable prognostic factor in the lung cancer.

• Keywords: Rb protein;Tumor suppressor gene;Lung cancer;Prognosis