Minichromosome maintenance protein 2 correlates with the malignant status and regulates proliferation and cell cycle in lung squamous cell carcinoma

Wei Wu,1,* Xianwei Wang,1,* Changting Shan,1 Yong Li,2 Fengzhu Li3 1Department of Respiratory Medicine, Affiliated Hospital of Jining Medical University, Jining, Shandong 272029, People’s Republic of China; 2Department of Emergency, Affiliated Hospital of Jining Medical University, Jining, Shandong 272029, People’s Republic of China; 3Department of Paediatric Surgery, Jining No 1 People’s Hospital, Jining, Shandong 272011, People’s Republic of China *These authors contributed equally to this work Background: Minichromosome maintenance protein 2 (MCM2), which is a member of MCM family, has been found to be a relevant marker for progression and prognosis in a variety of human cancers. Due to lack of effective therapeutic target in lung squamous cell carcinoma (LUSC) patients, the aim of our study was to screen and identify biomarkers which are associated to clinicopathological characteristics including prognosis in LUSC patients. Methods: The expression status of MCM2 in lung cancer was analyzed using the publicly available Gene Expression Omnibus databases (GSE3268 and GSE10245). The mRNA and protein expression of MCM2 in lung cancer tissues and cell lines was detected by quantitative real-time PCR and Western blot, and the association between MCM2 expression and clinicopathological factors was analyzed by immunohistochemistry. The loss-of-function study of MCM2 was conducted in LUSC cell lines. Results: In our study, we found MCM2 expression was increased in LUSC tissues compared with paired adjacent normal lung tissues or lung adenocarcinoma tissues through analyzing microarray data sets (GSE3268 and GSE10245), which confirmed that MCM2 mRNA and protein were overexpressed in LUSC tissues and cell lines. Meanwhile, we analyzed the association between MCM2 protein expression and clinicopathological characteristics of LUSC patients, and found high expression of MCM2 protein was obviously associated with malign differentiated degree, advanced clinical stage, large tumor size, more lymph node metastasis and present distant metastasis. The survival analysis showed MCM2 overexpression was an independent unfavorable prognostic factor for LUSC patients. Conclusion: MCM2 is involved in the development and progression of LUSC as an oncogene, and thereby may act as a potential therapeutic target for LUSC patients. Keywords: MCM2, lung cancer, lung squamous cell carcinoma, biomarker, proliferation, cell cycl