MCM2 is a component of the MCM complex, a replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. MCM2 is required for entry into the S phase and for cell division. MCM2 is a useful marker in immunohistochemistry for characterizing a number of cancers. It is overexpressed in precancerous and cancerous cervical lesions and upregulation is associated with high-risk type HPV. In squamous cell and adenocarcinoma of the gallbladder, MCM2 positivity is associated with metastasis and poor prognosis. It has similar prognostic value in oral dysplasia and ovarian serous neoplasms, where expression increases with severity of tumor grade. In immunohistochemistry of normal tissue, MCM2 has nuclear positivity in proliferative cells throughout the body. References: Int J Clin Exp Pathol. 2015; 8(1): 875–880, PMID: 25755789; Mol Med Rep. 2016 Nov; 14(5): 4581–4592, PMID: 27748889; Applied Immunohistochemistry & Molecular Morphology. 2018 Aug. 26(7):509–513, DOI: 10.1097/PAI.0000000000000330; British Journal of Cancer. 2004. 90:1583–1590, PMID: 15083189