LOSS OF EXPRESSION OF TRANSFORMING GROWTH-FACTOR-BETA TYPE-I AND TYPE-II RECEPTORS CORRELATES WITH TUMOR GRADE IN HUMAN PROSTATE-CANCER

Transforming growth factor beta 1 (TGF-beta 1) is a potential regulato r of prostate cancer cell growth that signals through a heteromeric co mplex composed of type I and type II receptors, In the present study, an attempt was made to establish a correlation between expression of T GF-beta receptors and tumor grade in archival human prostate cancer ti ssues, To this end, immunohistochemical studies for TGF-beta receptors were carried out on 32 cases of human prostate cancer and 8 samples o f benign human prostate, In both benign and malignant human prostate t issues, immunoreactivity for both type I and type II receptors was det ected predominantly in epithelial cells, In addition, there was an inv erse correlation between the loss of expression of TGF-beta 1 type I a nd type II receptors and the tumor grade. Of the 32 prostate cancer ca ses screened, staining was completely absent in four samples for type II receptor (P < 0.05) and eight samples for type I receptor (P < 0.02 5), In contrast, all eight samples of benign prostate tissues investig ated in this study showed strong staining for both type I and type II receptors. These results, taken together, indicate that human prostate cancer cells frequently have loss of expression of TGF-beta type I an d/or type II receptors, Furthermore, these observations provide a pote ntial mechanism for prostate cancer cells to escape the growth-inhibit ory effect of TGF-beta.