Specific Mutations in APC, with Prognostic Implications in Metastatic Colorectal Cancer.

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Loss-of-function mutations in the adenomatous polyposis coli (APC) gene are prevalent in metastatic colorectal cancer (mCRC).
• The specific characteristics and clinical implications of APC mutations in mCRC remain incompletely understood.

Purpose of the Study:

• To investigate the clinical and molecular distinctions between N-terminal and C-terminal APC gene mutations in Chinese patients with mCRC.
• To explore the prognostic value and differential gene-pathway associations of APC mutations in mCRC.

Main Methods:

• Hybrid capture-based next-generation sequencing of tumor tissues from 275 mCRC patients.
• Analysis of mutations across 639 tumor-associated genes.
• Prognostic value and gene-pathway difference analysis between APC mutation groups.

Main Results:

• APC mutations were found in 73% of mCRC patients, predominantly as truncating mutations.
• N-terminal APC mutation group showed significantly lower tumor mutation burden than the C-terminal group.
• Patients with N-terminal APC mutations exhibited longer overall survival compared to those with C-terminal mutations.
• C-terminal APC mutations were associated with higher mutation rates in RTK/RAS, Wnt, and TGF-β signaling pathways.
• Driver mutations like KRAS, AMER1, TGFBR2, and ARID1A were more frequent in the C-terminal group.

Conclusions:

• APC mutations serve as potential prognostic biomarkers in mCRC.
• Distinct gene mutation patterns exist between N-terminal and C-terminal APC mutations.
• These differences may guide precise treatment strategies for mCRC patients.