A Rare BRAF Fusion in Advanced Rectal Cancer Treated with Anti-Epidermal Growth Factor Receptor Therapy

Area of Science:

• Oncology
• Genomics
• Molecular Biology

Background:

• V-raf murine sarcoma viral oncogene homologue B (BRAF) fusions are rare oncogenic drivers identified across various cancers.
• Metastatic colorectal cancer (mCRC) with BRAF fusions represents a rare subset with limited targeted treatment options.
• Comprehensive genomic profiling (CGP) is crucial for identifying actionable molecular alterations in advanced cancers.

Observation:

• A 40-year-old female patient with metastatic rectal adenocarcinoma presented with disease recurrence after initial treatment.
• CGP analysis of the patient's tumor specimen revealed a novel EXOC4-BRAF fusion, previously unreported in colorectal cancer.
• The patient had a history of type 2 diabetes and underwent neoadjuvant therapy followed by R0 resection.

Findings:

• The identification of an EXOC4-BRAF fusion in a recurrent metastatic colorectal cancer case.
• The patient achieved a partial response to treatment with FOLFOX chemotherapy combined with panitumumab, an epidermal growth factor receptor inhibitor.
• This case represents the first reported instance of an EXOC4-BRAF fusion in colorectal cancer.

Implications:

• The findings highlight the potential of targeting BRAF fusions in mCRC, suggesting a new therapeutic avenue.
• Further research into the molecular mechanisms of EXOC4-BRAF fusions is warranted to develop more effective targeted therapies.
• This case underscores the importance of CGP in uncovering rare genetic alterations for personalized cancer treatment strategies.