There was a substantial subpopulation exhibiting ALDH activity as determined by functional Aldefluor assay (Fig. 1), therefore we investigated its contribution to drug responses in detail in three colorectal carcinoma cell lines (HCT-116/eGFP, HT-29/eGFP, LS-180/eGFP). This evidence concerns the gene LDHA and colorectal carcinoma.