BMPR1A and breast cancer: In AMHR2 signal transduction in BC and PC, three distinct subtypes of type I receptors for AMH are involved ALK2, ALK3 and ALK6 (26, 27) AMH inhibits the growth of BC cells that express ESRs (e.g., T47D) and those that do not (e.g., MDA-MB-231) (26) (Figure 6).