Procedure for improved diagnosis of dysplasias.

A method for discriminating dysplastic cells over-expressing INK4a gene products from other cells expressing INK4a gene products at a detectable level in biological samples comprising determining in a test procedure cytological or histological coexpression of at least two marker molecules in at least one cell, wherein at least one marker molecule is an expression product encoded by the INK4a gene and at least one other marker molecule is a cell proliferation marker, wherein overexpression of at least one product INK4a gene and the expression of at least one marker for active cell proliferation at a detectable level in said single cell is indicative of the dysplastic state of the cell and in which overexpression of at least one INK4a gene product and expression of at least one marker of senescence, terminal cell differentiation, apoptosis or stopping of Sickle cell cycle ar at a detectable level in said single cell is indicative of the dysplastic state not Cell.