Recurrent and functional regulatory mutations in breast cancer

Area of Science:

• Genomics
• Cancer Biology
• Molecular Oncology

Background:

• Genomic analysis has primarily focused on coding regions for cancer gene identification.
• Non-coding regions, particularly promoters, are understudied for their role in cancer development.

Purpose of the Study:

• To identify significantly mutated promoter regions in breast cancer using deep sequencing.
• To investigate the functional consequences of these promoter mutations on gene expression.

Main Methods:

• Deep sequencing of 360 primary breast cancer samples.
• Development of computational methods to detect significantly mutated promoters.
• Analysis of mutation impact on transcription factor binding and gene expression.

Main Results:

• Identified recurrent mutations in the promoters of three genes: FOXA1, RMRP, and NEAT1.
• FOXA1 promoter mutations lead to overexpression via increased E2F binding in hormone-receptor positive breast cancer.
• Mutations in RMRP and NEAT1 promoters alter protein binding and gene expression levels.

Conclusions:

• Promoter regions harbor recurrent, functionally significant mutations in cancer at frequencies comparable to coding regions.
• These findings highlight the importance of non-coding regions in cancer genomics.
• Further deep sequencing of large patient cohorts is needed to discover additional cancer-associated promoter mutations.