HPD and prostate cancer: The prostate cancer subtype S1 was characterized with high expression of AOX1, while S2 samples expressed high expression of MAOB, DBH, DDC, PNMT, HPD, TH, ADH1B, ADH4, and TAT. Compared with S2 (144 samples), we found the subtype S2 showed a higher level of regional lymph node involvement (X-square = 3.0881, P-value = 0.07).