After 72 hours of treatment, STB-HO inhibited the proliferation of cancer cells including prostate cancer (DU145 and PC3), glioblastoma (U87) and breast cancer (MDA-MB-231), whereas unexpected slight inhibition was observed in the proliferation of MCF-7 cells when same concentration of STB-HO was treated (Figure 3a–d and Suppl. The gene discussed is HMOX1; the disease is prostate cancer.