Tissues from mammary tumors that were spontaneously induced by DMBA or from human lung cancers showed a co-localization of and positive correlation between pHSF1 at Ser303/307 and MDR1, suggesting the possibility that targeting pHSF1 at Ser303/307 will overcome MDR1-mediated drug resistance in cancer therapy (Fig. 7c). This evidence concerns the gene ABCB1 and cancer.