Indeed, quantitative PCR analysis revealed that the mRNAs of two major ALDH isoforms expressed in the lung cancer cell lines, namely ALDH1A3 and ALDH1A1 [57, 58, 63], were significantly reduced by the TKI treatment, which strongly discouraged their induction by cisplatin (p < 0.05) (Figure 3F). The gene discussed is ALDH1A1; the disease is lung cancer.