Thymidylate synthase polymorphisms and immunohistochemistry in non-small cell lung cancer

11101 Background: Recently, pemetrexed has been introduced into the treatment of non-small cell lung cancer (NSCLC). There's evidence that pemetrexed appears to be more efficient in non squamous NSCLC including adenocarcinoma (AC) and large cell carcinoma (LCC). TS represents a major target enzyme of pemetrexed. We evaluated the expression of TS among different histological types of NSCLC and its association with functional genetic polymorphisms of the TS gene. Methods: Archived tumor samples from 312 individuals with NSCLC were analyzed. Immunohistochemistry (IHC) was performed using a mouse monoclonal antibody to TS. TS stained sections were scored for cytoplasmic and nuclear localization. For each compartment, the tumor was evaluated for the estimated percentage of positive cells with the greatest intensity within the tumor. Intensity was scored on a scale of 0–4. A score of 3–4 was classified as high expression. Genotyping of TS-VNTR including the G/C SNP and TS1394del6 was performed by PCR based RFLP...