Redefining synchronous colorectal cancers based on tumor clonality

Area of Science:

• Oncology
• Genetics
• Cancer Research

Background:

• Synchronous colorectal cancer (SCRC) presents a complex challenge in understanding its origins and predicting patient outcomes.
• Previous studies have explored the clonal architecture of colorectal cancers, but the specific origins of SCRCs remain incompletely understood.

Purpose of the Study:

• To investigate the clonal origin of synchronous colorectal cancer (SCRC) in patients without hereditary forms of the disease.
• To establish a classification system for SCRC based on clonality and colonic location to identify differential phenotypes and prognostic value.

Main Methods:

• Genomic profiling of 104 paired-SCRCs from 52 patients using Single-Nucleotide Polymorphism (SNP) arrays.
• Application of a statistical tool to determine tumor clonality (monoclonal vs. polyclonal) within individuals.
• Categorization of SCRC groups (Monoclonal and Polyclonal) by colonic location (Monosegmental and Pancolonic) to analyze phenotypes.

Main Results:

• The study identified both monoclonal and polyclonal origins for SCRCs, with polyclonal cases being more frequent.
• Specific SCRC subtypes (e.g., Monosegmental Monoclonal, Pancolonic Polyclonal) exhibited distinct characteristics, including mucinous components, tumor/polyp numbers, and prognosis.
• Differential genomic regions were identified for monoclonal and polyclonal SCRCs, with gains on 1q24 and 8q24, and deletions on 1p21 and 1p23 in Monosegmental Monoclonal cases, and gains on 7q36 and deletions on 1p36 in Monosegmental Polyclonal cases.

Conclusions:

• Synchronous colorectal cancer is more likely to be polyclonal in origin, challenging previous assumptions.
• A classification system integrating clonality and tumor location provides significant prognostic and clinical value for SCRC management.
• Further research into the genomic underpinnings and clinical implications of SCRC clonality is warranted.