HSD17B1 and breast cancer: Several compounds with inhibitory action on the enzyme HSD17B1 have been developed and one steroidal compound, a competitive HSD17B1 inhibitor (OG-6219) recently entered the clinical phase for endometriosis (https://www.elenaendometriosisstudy.com/#!/) and it is in the preclinical phase for endometrial and breast cancer (Husen et al., 2006a; Husen et al., 2006b; Konings et al., 2018b; Jarvensivu et al., 2018; Xanthoulea et al., 2021).