Mast cells influence neoangiogenesis in prostatic cancer independently of ERG status

A significant proportion of prostatic adenocarcinomas show recurrent translocation leading to ERG expression. Previously we found that ERG+ cases have higher microvessel density than negative ones. One factor influencing angiogenesis in cancer is mast cells. The aim of the present study was to evaluate the relationship between microvessels, mast cells and ERG status. Tissue microarrays prepared from 113 radical prostatectomy specimens were analyzed with immunohistochemistry for CD31, tryptase and chymase. Vascular profiles and tryptase-positive and chymase-positive cells were counted. The average number of tryptase-positive cells was 28.93/mm² and chymase-positive cells 9.91/mm². The average number of CD31+ vascular profiles was 352.66/mm². The average number of tryptase-positive cells was 26.35/mm² for ERG- cases and 32.12/mm² for ERG+ cases. The average number of chymase-positive cells was 8.14/mm² for ERG- cases and 12.06/mm² for ERG+ cases. The average number of CD31+ vascular profiles was 321.34/mm² for ERG- cases and 390.74/mm² for ERG+ cases. The number of CD31+ vascular profiles was positively correlated with the number of tryptase-positive and chymase-positive cells (R = 0.26 and R = 0.20). In summary, we demonstrated an interrelationship between mast cells, microvascular density and ERG status in prostatic carcinoma.