Mucinous borderline ovarian tumors with BRAF(V600E) mutation may have low risk for progression to invasive carcinomas

PURPOSE: Mucinous ovarian carcinomas (MOCs) are relatively rare. It has been proposed that a subset of mucinous cystadenomas (MCAs) may progress to mucinous borderline tumors (MBTs), and then to MOCs. KRAS is the predominantly mutated gene in MOC; however, other associated mutations and the mechanism underlying carcinogenesis in MOC remain unclear. Here, we assessed molecular genetic alterations in mucinous ovarian tumors and constructed mutation profiles. METHODS: Using the Sanger sequencing method, we assessed genetic mutations (KRAS, BRAF, TP53, and PIK3CA) in 16 cases of MOC, 10 cases of MBT, and 12 cases of MCA. RESULTS: Among MOC cases, the prevalence of G12D and G13D KRAS mutations was 43.8% (7/16). No MOC cases showed V600E BRAF and TP53 mutations. Among MBT cases, the prevalence of G12D KRAS mutation was 20.0% (2/10), those of TP53 and PIK3CA mutations were nil, and that of V600E BRAF mutation was 40% (4/10). None of the genetic mutations assessed were detected among MCA cases. CONCLUSION: These results suggest that MBT with V600E BRAF mutation may rarely progress to MOC, while MBT with G12D or G13D KRAS mutation may more commonly progress to MOC.