Cell proliferation, apoptosis, oncogene, and tumor suppressor gene status in adenosis with comparison to benign prostatic hyperplasia, prostatic intraepithelial neoplasia, and cancer

Abstract

There is scant information on the cell proliferation, apoptosis, oncogenes, and tumor suppressor genes status in adenosis. Forty-eight foci of adenosis were studied with immunohistochemistry for MIB-1; c- erbB-2, c- erbB-3, bcl-2 oncogenes; and p53. To evaluate apoptosis, the TdT dUTP nick end labeling (TUNEL) method was applied. Results were compared with the same studies on benign prostatic hyperplasia (BPH) ( n = 20), low-grade prostatic intraepithelial neoplasia (PIN) ( n = 10); high-grade PIN ( n = 20), Gleason sum 2 to 6 cancer ( n = 16); and Gleason sum 7 to 10 cancer ( n = 22). MIB-1 proliferation index was lowest in BPH, followed by adenosis, low-grade prostatic intraepithelial neoplasia (PIN), low-grade cancer, high-grade PIN, and high-grade cancer. The apoptotic rate was generally low in all groups, although it was higher in PIN and cancer. In BPH and adenosis, bcl-2 was absent in luminal cells. In low- and high-grade PIN, both basal and luminal cells expressed bcl-2, whereas in cancer, expression was found in only 1 case (3%). C- erbB-2 showed absent or low values for cancer and adenosis, whereas it was commonly expressed in BPH and low- and high-grade PIN. Low expression in adenosis was also found with c- erbB-3 (6%) compared with all other groups. Expression of p53 was confined to cancer. Despite a significantly higher proliferation index rate compared with BPH, adenosis showed a markedly lower proliferating index when compared with low-grade PIN, high-grade PIN, and cancer. Expression of the oncogenes c- erbB-2 and c- erbB-3 was very low in adenosis, and the staining pattern for bcl-2 was similar to that of BPH. These results provide additional evidence to that of prior studies that adenosis is a histological small acinar proliferation more akin to BPH than high-grade PIN or adenocarcinoma.