LIN-28B/let-7a/IGF-II axis molecular subtypes are associated with epithelial ovarian cancer prognosis

OBJECTIVES: Aberrant expressions of LIN-28B, let-7a and IGF-II occur in epithelial ovarian cancer, and the LIN-28B/let-7a/IGF-II axis is associated with human disease. The purpose of this study was to investigate the associations between LIN-28B/let-7a/IGF-II axis molecular subtypes and epithelial ovarian cancer prognosis. METHODS: Using quantitative reverse transcription PCR, we analyzed LIN-28B, let-7a and IGF-II mRNA in 211 primary epithelial ovarian cancer tissues, and also performed Classification and Regression Tree (CART) and survival analyses. RESULTS: Four terminal subtypes were identified in the CART analysis in combination with survival analysis. Kaplan-Meier survival curves showed that subtypes LIN-28B(low)let-7a(low) and LIN-28B(low)let-7a(high)IGF-II(low) had significantly better survival than subtypes LIN-28B(high) or LIN-28B(low)let-7a(high)IGF-II(high) (p<0.0001 for overall, p=0.017 for progression-free survival, respectively). Multivariate Cox regression models showed that compared to subtype LIN-28B(high), subtypes LIN-28B(low)let-7a(low) and LIN-28B(low)let-7a(high)IGF-II(low) had significantly reduced mortality and reduced relapse risks. Moreover, subtype LIN-28B(low)let-7a(low) had better response to chemotherapy than subtype LIN-28B(high). CONCLUSIONS: These results suggest that molecular subtypes of the LIN-28B/let-7a/IGF-II axis associate with heterogeneous progression and may have clinical implications in predicting epithelial ovarian cancer prognosis.