IMP3 is upregulated in primary ovarian mucinous carcinoma and promotes tumor progression

Objective: Primary ovarian mucinous tumors progress from benign adenoma to borderline tumors to invasive mucinous carcinoma. A proper differential diagnosis is crucial to discriminate malignancies at the early stages of disease. However, few biomarkers are clinically available. We designed this study to analyze the clinical application of the oncogene IMP3 in monitoring early malignancies in ovarian primary mucinous tumors.

Methods: We collected 250 samples of ovarian primary mucinous tumors along with the corresponding clinicopathological information between 2009 and 2015 at the Gynecology and Obstetrics Hospital of Fudan University and performed immunochemical assays. Statistical analysis of the correlation between expression of IMP3 and clinic-pathological parameters as well as the survivals of these patients was carried out. Finally, wound-healing and transwell assays were performed in SKOV3 and CAOV3 cells.

Results: The expression rate and intensity of IMP3 were much higher in invasive carcinoma than those in benign adenoma and classic borderline adenoma (P<0.05). The expression rate and intensity of IMP3 were also higher in cases with mucinous intraepithelial carcinoma than those in cases with classic borderline tumors (P<0.05). Among the malignant cases, the expression rate and intensity of IMP3 increased with advancing FIGO staging (P<0.05). The expression rate and intensity of IMP3 were much higher in cases with involved fallopian tubes, uterine and omentum than those in cases without the involvement of these tissues (P<0.05). The expression rate and intensity of IMP3 were much higher in cases with lymph node metastasis than those in cases without lymph node metastasis (P<0.05). Elevated expression of IMP3 significantly deteriorated the disease-free survival (DFS) and overall survival (OS) of mucinous carcinoma (P<0.05). IMP3 was an independent risk factor of DFS but not OS. Further in vitro experiments indicated that IMP3 promoted the proliferation, motility and invasive potential of ovarian tumor cells.

Conclusions: IMP3 is highly expressed in ovarian mucinous tumors and is positively correlated with malignancy. IMP3 could be used in the differential diagnosis of ovarian mucinous tumors and might be applicable in monitoring tumor initiation and progression.