Prostate tumor progression and prognosis: interplay of tumor and host factors

The prognosis for prostate cancer is largely dependent on the probability of metastatic dissemination. Prognostic markers currently in use are very poor predictors of metastatic potential, and as of yet none of the battery of new molecular markers has proven greatly superior. This may be due in part to their inability to assess the degree of interaction of subpopulations of prostate cancer cells with each other and with their microenvironment. A growing body of evidence indicates that these types of interactions are a major factor in the eventual genesis of cancer cells capable of metastasis. Recent research has demonstrated that specialized components of prostate tumors may play a critical supporting role for the overall growth of the larger tumor. The multifocal nature and apparent polyclonal origins of prostate tumors suggest that carcinogenesis and tumor progression are promoted by global influences or “field effects.” It appears that these effects extend beyond the proliferating epithelial component to the tissue stroma. Prostate cancer cells and stromal cells seem to act in concert to modify the microenvironment, leading to metastasis. An understanding of this synergy may provide a new class of prognostic markers which more accurately measure the complex set of interactions that determine tumor behavior.