qRT-PCR conducted to evaluate the expression of genes encoding additional β subunits that may pair with αV integrin showed that ITGB1 and ITGB5 mRNA were equally expressed in tumours than in adjacent healthy lungs (n = 15) and that ITGB3 was more strongly expressed in two tumours than in healthy lungs (Supplementary Fig. 2b). This evidence concerns the gene ITGB3 and neoplasm.