▁only ▁one , ▁as ▁mentioned ▁above ) ▁is ▁the ▁foc al ▁type , ▁which ▁refers ▁to ▁a ▁conventional ▁pro static ▁ad en oc arc in oma ▁that ▁exhib its ▁ne uro end ocr ine ▁fo ci ▁at ▁hist op ath ological ▁exam ination . ▁T um or ▁x en og raft s ▁of ▁m ice ▁subject ed ▁to ▁cas tr ation ▁have ▁been ▁shown ▁to ▁under go ▁rapid ▁regression ▁with ▁a ▁dram atic ▁drop ▁in ▁and ro gen ▁re ceptor ▁expression ▁in ▁tum or ▁cells ▁and ▁a ▁ste ep ▁increase ▁in ▁the ▁proportion ▁of ▁apo pt otic ▁cells ▁Following ▁cas tr ation , ▁the ▁proportion , ▁as ▁well ▁as ▁the ▁density ▁of ▁ne uro end ocr ine ▁tum or ▁cells , ▁r ises ▁ab rupt ly , ▁eventually ▁leading ▁to ▁the ▁formation ▁of ▁ne uro end ocr ine ▁cell ▁is lets ▁that ▁are ▁spread ▁throughout ▁the ▁tum or ▁and ▁account ▁for ▁the ▁majority ▁of ▁its ▁constitu ent ▁cells . ▁ ▁The ▁imm un oh ist och em ical ▁phen ot ype ▁of ▁foc al ▁ne uro end ocr ine ▁different iation ▁in ▁pro state ▁cancer ▁has ▁been ▁intens ively ▁studied . ▁Ch rom og ran in ▁A , ▁which ▁is ▁the ▁most ▁abund ant ▁product ▁of ▁pro static ▁ne uro end ocr ine ▁cells ▁and ▁ne uro end ocr ine ▁tum or ▁cells , ▁is ▁widely ▁recognized ▁as ▁a ▁reliable ▁marker ▁for ▁ne uro end ocr ine ▁different iation . ▁Syn apt oph ys in ▁and ▁neur on - specific ▁en ol ase