[Dysplasia and cancer].

Problems of morphological features and nature of dysplasia and its role in blastomogenesis are discussed. It is pointed out that the term "dysplasia" is used in modern pathology to designate various processes including disembryogenetic, adaptive-hyperplastic and pretumourous ones. The necessity of a uniform interpretation of this term is underlined, its definition is given and it is suggested to distinguish between metaplastic processes and dysplasia. An important role of advanced dysplasia as a precancerous process is shown; due to this it should serve as one of the most important criteria for the formation of groups of increased cancer risk. As the problem of dysplasia is a biological one it can be solved only on the basis of fundamental multidisciplinary research; this may help in the unveiling essence of processes of malignization.