I think I had. Correct if I'm wrong, they showed that PGD2 was overexpressed in balding scalp, whereas PGE2 was underexpressed. This doesn't address my question, though. By this time, I believe that PGE2 administration has not been proven as an effective treatment in any group of patients; and, according to some, Brotzu for example (and I know that he is not the most trustworthy person at this point), PGE2 has been proven ineffective in experiments. The theory is interesting, but what about the empirical data?
PGE2 has been linked to a number of diseases, including cancer
Prostaglandin E2 (PGE2) promotes proliferation and invasion by enhancing SUMO-1 activity via EP4 receptor in endometrial cancer.
https://www.ncbi.nlm.nih.gov/pubmed/27230680
and its role as a treatment of male pattern baldness it is just based in speculation. Its plausible mechanisms of action are, as far as I know, not well understood, and the risks are far too great. At this point, I don't believe that it is wise to self-treat oneself with a pro-inflammatory prostaglandin, that could go systemic and break havoc in several parts of your body.