Regulation of APOBEC3A in breast cancer

APOBEC-associated mutations have been identified in 50% of sequenced tumors, with APOBEC3A (A3A) implicated as the primary source of mutations in breast cancer cells. However, the mechanisms behind A3A activation and mutagenesis in breast cancers are still unknown. We found that A3A mRNA correlates with A3A protein levels as well as APOBEC signature mutations in a panel of breast cancer cell lines. Additionally, we identified transcription factor binding sites within the A3A promoter region, which when altered demonstrated a negative regulatory effect on A3A. Together these findings demonstrate that transcriptional regulation of A3A may play a role in breast cancer mutagenesis.