To investigate how cancer cells deal with cellular stress in the case of HSF1 deficiency, we analyzed the global gene expression profiles in breast adenocarcinoma MCF7 cells with decreased HSF1 levels (HSF1-deficient, HSF1def) and corresponding control cells with normal HSF1 levels (HSF1-proficient, HSF1prof) (cell model described previously in [17]). The gene discussed is HSF1; the disease is cancer.