Expression of class III beta tubulin in non-small cell lung cancer is correlated with resistance to taxane chemotherapy

International audience; This study determined the prevalence and the prognostic value of the expression of microtubule components in tumors of 19 patients with non small cell lung cancer receiving taxane-based regimens. Patient samples were stained with antibodies directed against total β tubulin, classes I, II and III β tubulin isotypes, δ2 alpha tubulin, τ protein, and the P-gp protein involved in the classical multidrug resistance phenotype. All tumors were stained with pan-β tubulin antibody and class I tubulin isotype. A majority of the tumor samples expressed class II and class III, although the percentage of positive cells varied significantly between tumors. δ2 alpha tubulin, τ protein and Pgp protein were found in only one tumor sample each. Progression-free survival was shorter (41 days) in patients whose tumors expressed high levels of class III tubulin isotype in comparison to patients with low levels (288 days, p = 0.02). There were 2 responses to chemotherapy among 9 patients (22%) with high levels of class III tubulin vs. 6 among 10 patients (60%) with low levels of expression (Fisher exact test: p = 0.11). These data suggest that high expression of class III tubulin by tumor cells is associated with poor prognosis in patients with NSCLC receiving a taxane-based regimen.