Synthetic steroids encompass a wide range of compounds with various specific anticancer activities, e.g., aromatase inhibitors such as formestane and exemestane (Carlini et al., 2001), antiproliferative agents such as 2-methoxyestradiol (Lakhani et al., 2003), androgen signaling inhibitors such as galeterone and abiraterone (Bryce and Ryan, 2012), the SERM compound PSK3471, the steroid sulfatase inhibitor EMATE (Purohit and Foster, 2012), and the selective estrogen receptor degrader (SERD) fulvestrant (Nathan and Schmid, 2017; Figure 1).