MCM7 expression is correlated with histological subtypes of lung adenocarcinoma and predictive of poor prognosis

Emerging evidence has implicated that the abnormal expression of MCM3 and MCM7 contributes to tumor formation and progression. However, MCM3 and MCM7 protein expression in different subtypes of lung adenocarcinoma have not yet been reported. In the present study, we detected MCM7 and MCM3 protein level in five subtypes of lung adenocarcinoma by immunohistochemistry. The five subtypes can be divided into 3 grades-grade 1: lepidic adenocarcinoma, grade 2: acinar or papillary adenocarcinoma and grade 3: solid or micropapillary adenocarcinoma. The immunostaining showed that MCM7 level was lowest in the grade 1 subtype and highest in the grade 3 subtypes. The statistical analysis proved that MCM7 expression increased step wisely with the ascending of tumor grades. However, there is no significant relationship between MCM3 expression and tumor grades. In addition, we investigated the association of MCM7 and MCM3 expression with clinicopathological characteristics. The results showed that tumors with lymph node metastasis had higher MCM7 level than those without lymph node metastasis statistically (P<0.0001). MCM3 expression has no significant relationship with clinicopathological characteristics. In conclusion, our results suggested that MCM7 may be a useful biomarker for the pathological diagnosis of subtypes of lung adenocarcinoma and it also may be a potential prognostic marker for lung adenocarcinoma.