MHC class I and class II molecules are expressed in both human and mouse prostate tumor microenvironment.

Background: There has been a determined search for therapies specifically aimed at eradicating tumor cells while leaving normal host cells unaffected. This goal can potentially be accomplished by engaging tumor antigen-specific T-cell repertoire to attack the tumor. A pre-requisite for a successful T-cell-mediated attack against tumors or pathogens is that the target tissues express major histocompatibility complex (MHC) molecules. Using newer anti-MHC class I and MHC class II antibody reagents, we re-examined the expression of MHC in both human and mouse prostate tumors and their microenvironments.

Methods: Using immunocytochemistry, we examined the expression of MHC class I, class II, and CD3 molecules on cryopreserved human and mouse prostate tumor samples.

Results: MHC class I molecules are expressed by the entire spectrum of different stages of both human and mouse prostate tumor cells. Additionally, cells of the hematopoietic lineage, dispersed in the tumor microenvironment, showed significant expression of MHC class II molecules. Human prostate tumors also show a significant infiltrate of CD3+ T cells.

Conclusions: Expression of MHC class I and class II molecules within the prostate tumor microenvironment are consequential for T-cell-mediated immunotherapeutic approaches against prostate cancer.