Quantitative analysis of transforming growth factor beta 1 and 2 in ovarian carcinoma

Transforming growth factor beta (TGF-beta) is an important family of cytokines that may promote tumor growth in vivo through several mechanisms including interference with antitumor T-cell immune responses, alteration of factors in the stroma and matrix, and the promotion of angiogenesis. TGF-beta isotypes have been detected in malignant and normal ovarian tissues. We have determined by quantitative immunohistochemistry the density of TGF-beta1, TGF-beta2, and human leukocyte antigen (HLA) Class I and Class II antigens on malignant cells in paired primary and metastatic specimens from 10 patients with ovarian carcinoma. Cryostat sections of specimens from the carcinomas and from normal ovaries of three women of similar age without ovarian cancer were stained respectively with specific antibodies to TGF-beta1, TGF-beta2, and HLA Class I and II antigens, and with isotype-matched control antibodies. Antigen density was quantitated blindly as mean absorbance on a SAMBA 4000 image analyzer. TGF-beta1 and TGF-beta2 were overexpressed in both primary and metastatic tumor specimens in comparison with normal ovarian tissue. No statistical correlation was found between the expression of TGF-beta1 or TGF-beta2 and HLA class I or HLA class II, which suggests that TGF-beta isotypes could have effects on the immune system other than down-modulation of these HLA molecules. Furthermore, the lack of association between levels of TGF-beta expression and the reduced expression of HLA molecules could suggest that tumor cells expressing both HLA and TGF-beta may be suitable targets for adaptive immunotherapy. Additional studies are necessary to determine whether TGF-beta expressed by ovarian cancer cells merits evaluation as a therapeutic target.