Proliferating Cell Nuclear Antigen: A New Marker of Proliferation in Cancer

Proliferating cell nuclear antigen (PCNA) is the auxiliary protein of DNA polymerase δ It is induced in late G1 and S phases following mitotic stimulation of resting cells and is required for efficient DNA synthesis and cell cycle progression. Its expression in normal and malignant proliferating cells is related to proliferative activity. Because of the potential for substantial variability between proliferating cell populations with respect to the proportions of cells in G0 or G1, assays of PCNA can complement DNA analysis for assessment of proliferative activity in malignant cells and tissues. Data with respect to expression of PCNA in leukemia and in some solid tumors will be reviewed.