MUTATIONAL PROFILING OF BRAZILIAN MUCINOUS ADENOCARCINOMA OF THE OVARY

Objectives To investigate the mutational profiling associated with Brazilian mucinous adenocarcinoma of ovary. Methods We included 47 patients from Barretos Cancer Hospital, from 2009 and 2015. The mutation profile of a panel of hotspot regions of 15 cancer drivers (AKT1, BRAF, EGFR, ERBB2, FOXL2, GNA11, GNAQ, KIT, KRAS, MET, NRAS, PDGFRA, PIK3CA, TP53) was performed by NGS using the Illumina TruSight Tumor 15 panel on MiSeq instrument (Illumina, USA) in a subset of cases. Hotspots regions of the KRAS (codons 12 and 13) were screened by PCR followed by direct Sanger sequencing. Finally, HER2 amplification was evaluated by immunohistochemistry (IHC) and in situ hybridization (FISH). Results HER2 IHC was performed in 27 samples that showed absence of staining in 25 (92.6%). Two samples (7.4%) showed inconclusive IHC reaction, and FISH analysis showed HER2 amplification in both cases. Clinically, both cases had pseudomixoma peritonei and 1 had disease recurrence. For KRAS Sanger sequencing, conclusive results were obtained in 25 cases due to DNA quality issues. KRAS mutations were found in 10 samples (40%), and were associated with no recurrence (p=0.036). The TruSight Tumor 15 panel was possible only in 16 samples. All samples showed at least one mutation in one gene and the most mutated genes were: TP53 and KRAS (10 mutations each), BRAF (4) and HER2 and PIK3CA (1). Conclusions We identified potential therapeutic targets in Brazilian mucinous adenocarcinoma of ovary that could be investigated in future new clinical trials. In addition, the presence of KRAS mutations was associated with better patient outcome.