The aims of the present study were to investigate the expression of minichromosome maintenance complex component 7 (MCM7) and determine its association with tumor proliferation and invasion in pathological tumor (pT)a and pT1 papillary urothelial neoplasia. The MCM7, MCM3 and Ki67 proteins were detected in 154 cases of urothelial neoplasia using immunohistochemical analysis. The expression of MCM7 significantly increased (P<0.001) as the pathological stage and grade progressed between inverted papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), pTa tumor and pT1 tumor. However, no statistically significant difference in MCM7 staining was observed between low-grade pTa tumors and PUNLMP (P=0.2294). In contrast to MCM7, MCM3 was highly expressed in all stages of urothelial neoplasia, with no statistically significant differences observed between the tumor types (P=0.2993, 0.3885 and 0.8489 for pTa tumors, PUNLMP and inverted papiloma, respectively). Furthermore, MCM7 expression was elevated with increased tumor grade and was positively correlated with Ki67 expression (rs =0.9106, P<0.001). However, MCM3 expression was not correlated with MCM7 or Ki67 expression (rs =0.0734, P=0.3657 and rs =0.0638, P=0.4318, respectively). In conclusion, MCM7 overexpression may simultaneously promote tumor proliferation and invasion. Furthermore, it may be a reliable marker for the pathological differential diagnosis of pTa and pT1 papillary urothelial neoplasms; therefore, MCM7 expression may be used to predict tumor prognosis and behavior.
Keywords: MCM3; minichromosome maintenance complex component (MCM)7; papillary neoplasm; urothelial neoplasia.