In preclinical studies performed by us and others in vivo, HSD17B1 inhibition was shown to reduce the growth of breast cancer xenografts [45,46,47,48], the development of inflammation-aided mammary epithelial rupture [20], the growth of endometrial cancer xenografts on chicken chorioallantoic membrane [49], the development of endometrial hyperplasia phenotype [16], the pain-related behavior of marmoset monkeys with endometriosis [50], the uterus weight induction and proliferation in uterotropic assay [19], the ERELuc reporter construct activity [19,20] and the serum E1 to E2 conversion [51]. This evidence concerns the gene HSD17B1 and breast cancer.