The aim of the present study was to investigate the immunohistochemical expression of MCM-2 and MCM-5 proteins in a series of low malignant potential (LMP) tumours and ovarian carcinomas of all histologic types and to determine for the first time the possible associations with clinicopathologic parameters, the conventional proliferation index Ki-67, other cell cycle regulators (p53, p27Kip1, p21WAF1 and pRb) and patients’ outcome. The gene discussed is CDKN1B; the disease is neoplasm.