The authors have demonstrated that 6-substituted-imidazo[1,2-a] pyridine derivatives inhibited ALDH1A1 and ALDH1A3 gene expression and the proliferation of cancer cell line PC3, normal prostate epithelial cell line PNT2-C2, and benign prostatic hyperplasia cell line BPH1 [50]. This evidence concerns the gene ALDH1A1 and cancer.