DR-103 BRAF and RNF43 copy number variation and mutant allele frequency in BRAF/RNF43 mutant colorectal cancer.

An aggressive subtype of colorectal cancer (CRC) harbours activating mutations in the BRAF oncogene and inactivating mutations in the RNF43 tumor suppressor gene. The purpose of this study is to assess BRAF and RNF43 copy number variation (CNV) and mutant allele frequency (MAF) in these tumors. Using whole genome sequencing data from BRAF/RNF43 mutant tumors we aim to assess whether selective amplification of the mutant BRAF allele is a frequent event in mCRC, and how this relates to loss of RNF43. Such genetic events may have an impact on the tumor response to drugs targeting the MEK/ERK and WNT pathways.

Onno Kranenburg University Medical Center Utrecht the Netherlands