In view of previous reports on Hsp90 inhibitors and their effects on cancer cell viability (Eachkoti et al. 2014) and clonogenicity (Kinzel et al. 2016), new compounds were tested for inhibition of cell viability within both non‐tumourigenic (HEK‐293) and breast cancer cell lines (MDA‐MB‐231) at a fixed concentration of 10 μM. This evidence concerns the gene HSP90AB1 and breast cancer.