Prognostic value of class III b-tubulin (TUBB3) in operable non-small cell lung cancer (NSCLC) and predictive value for adjuvant cisplatin-based chemotherapy (CT): A validation study on three randomized trials

7506 Background: The IALT and JBR.10 randomized trials both demonstrated the survival advantage of adjuvant platinum-based CT for patients with resected NSCLC. We previously showed by immunohistochemistry (IHC) that high TUBB3 expression might correlate with greater benefit from adjuvant vinorelbine/cisplatin CT in an analysis of tumor tissues from 265 patients in the JBR.10 trial. Here, we sought to verify the previous suggestions in the IALT trial. Since some CT regimens in the IALT trial did not include an anti-tubulin agent, we also tested the hypothesis that the value of TUBB3 expression in predicting benefit from CT was specific to anti-tubulin containing regimens. Methods: Tissue microarrays representing 737 patients on the IALT trial were stained for TUBB3. A score was generated based on the intensity and the proportion of positive-staining tumor cells in each case. Patients were classified as having high or low TUBB3 expression based on the median score. Correlations were assessed between TUBB3 a...