PROSTATIC INTRAEPITHELIAL NEOPLASIA AND OTHER CHANGES DURING PROMOTION AND PROGRESSION

Preneoplastic lesions, early neoplastic lesions and carcinomas in situ have been demonstrated to be of great value for many purposes in many organ systems. Their recognition can be useful in epidemiological stu dies and can facilitate the selection of patients for therapeutic inte rventions. They can be used as ''surrogate endpoint biomarkers'' in st udies aimed at the chemoprevention of cancers. In the lung, colon and various other organs, such markers are well recognized to be associate d with the development of cancer in man. In the livers and colons of e xperimental animals, there has been detailed characterization of ''enz yme-altered foci'' (EAF) as ''putative preneoplastic markers.'' The wo rds ''surrogate'' and ''putative'' are important; the biological poten tial of these lesions needs to be elucidated in much greater detail. T he quantification of early lesions that are associated with and someti mes precursors of neoplasia is of particular value because they are mu ch more numerous, in most organ systems, than the carcinomas that deve lop in the same organs. The most abundant of these lesions show minima l or no morphological alterations. For example, EAF and aberrant crypt s are more numerous than polyps in the colons of patients and experime ntal animals with cancer or precancerous conditions that affect the co lon. Currently, there are few well documented putative or surrogate ma rkers that are highly associated with the development of prostatic car cinoma in man. The best documented among these is prostatic intraepith elial neoplasia. We have recently reported the identification of EAF i n the human prostate. While they share many phenotypic alterations wit h prostatic intraepithelial neoplasia, much remains to be accomplished if their biological fate is to be understood.