Although in a murine A549 lung cancer xenograft model, a genetic (LDHA knockout) and chemical (tamoxifen) inactivation of LDHA has been shown to inhibit tumorigenesis [38], very low concentrations of diclofenac (0.1, 0.2 mM) had no effect on LDHA/B expression or the stress response (HSF-1, Hsp70, Hsp27) in lung (A549), breast (MDA-MB-231) and pancreatic (Colo357) cancer cells, but in adenocolorectal (LS174T, LoVo) cancer cells. This evidence concerns the gene HSF1 and cancer.