Fact of life: breasts and prostate usually do not belong to the same person and they are different cancers.
But the fact that they are both hormonal cancers and the fact that this molecule is targeted (very succesfully in vivo) to bone metastasis, makes me say "keep an eye on this!"
"Such findings indicate that RK-33 was able to successfully target, halt the growth of and fully eliminate breast cancer bone metastasis cells by inhibiting DDX3 and successfully penetrating bone microenvironments that often block other therapies. "...the part in bold is quite crucial...
PSMA PET scan results 
Targeting a single enzyme can kill prostate cancer cells
Antioxidant and metastasis
Aspirin’s anti-metastatic effects. 
