Proliferating cell nuclear antigen expression in childhood acute leukemia.

Proliferating cell nuclear antigen (PCNA) is a 36-Kd nuclear protein, identified as the auxiliary protein of DNA polymerase delta, that is upregulated in activated proliferating cells from a variety of tissues and species, including human lymphocytes. We have examined by two-dimensional polyacrylamide gel electrophoresis the expression of PCNA in various subtypes of childhood acute leukemia and have found differences in its expression according to subtype. These differences were not related to the initial peripheral white blood count, age, or sex, and appeared to reflect differences in proliferative activity between subtypes of acute leukemia.