Prognostic Value Of hMLH1 and hMSH2 Immunohistochemical Expression In Non-Small Cell Lung Cancer

Purpose and Experimental Design: The etiologic association and prognostic significance of mismatch repair gene/protein alterations have never been examined in lung cancer. We investigated protein expression of hMLH1 and hMSH2 genes in tumor specimens from 105 non–small cell lung cancer (NSCLC) patients. 60 of them were diagnosed with adenocarcinoma, 38 with squamous cell carcinoma and seven with large cell carcinoma. Out of the 105 patients 40 (20 adenocarcinomas and 20 squamous cell carcinomas) had already received neoadjuvant chemotherapy based on Carboplatine and navelbine or carboplatine vepesid. Immunohistochemical staining was used to examine protein expression. Expression in each patient was compared with clinicopathologic variables as well as overall survival and cancer-specific survival rates. Results: Alteration of protein expression was observed in 30% of patients. Loss of hMLH1 and hMSH2 protein expression was associated with significantly shorter disease-free survival in patients who had received neoadjuvant chemotherapy (p=0.1). Conclusion: Loss of immunohistochemical expression of hMLH1 and hMSH2 markers in lung tumors indicates a poorer prognosis for NSCLC patients receiving neoadjuvant therapy.