The extended spectrum of RAS-MAPK pathway mutations in colorectal cancer
Danielle C Costigan1, Fei Dong1
1Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Abstract:
Current clinical guidelines recommend mutation analysis for select codons in KRAS and NRAS exons 2, 3, and 4 and BRAF V600E to guide therapy selection and prognostic stratification in advanced colorectal cancer. This study evaluates the impact of extended molecular testing on the detection of RAS-MAPK pathway mutations. Panel next-generation sequencing results of colorectal cancer specimens from 5795 individuals from the American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange (AACR Project GENIE) were included. Mutations in RAS-MAPK pathway genes were analyzed and functionally annotated. Colorectal cancers had recurrent pathogenic pathway activating mutations in KRAS (44%), NRAS (4%), HRAS (<1%), BRAF (10%), MAP2K1 (1%), RAF1 (<1%), and PTPN11 (<1%). The proportion of colorectal cancers with pathogenic RAS pathway mutations was 37% when only KRAS codon 12 and 13 mutations were considered, 46% when also including select KRAS and NRAS exons 2, 3, and 4 mutations, 53% when including BRAF V600E mutations, and 56% when including all pathogenic mutations. Panel next-generation sequencing testing identifies additional RAS-MAPK pathway driver mutations beyond current guideline recommendations. These mutations have potential implications in treatment selection for patients with advanced colorectal cancer.
Insights
Extended molecular testing for colorectal cancer detects more RAS-MAPK pathway mutations than current guidelines recommend. This comprehensive analysis, using panel next-generation sequencing, identifies additional drivers that may impact treatment selection for advanced cases.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Current clinical guidelines for advanced colorectal cancer (CRC) recommend specific mutation analyses (KRAS, NRAS, BRAF V600E) for therapy selection.
- These guidelines may not capture the full spectrum of RAS-MAPK pathway alterations relevant to CRC treatment.
Purpose of the Study:
- To evaluate the impact of extended molecular testing on detecting RAS-MAPK pathway mutations in colorectal cancer.
- To determine the frequency of various RAS-MAPK pathway mutations beyond current guideline recommendations.
Main Methods:
- Analysis of panel next-generation sequencing data from 5795 colorectal cancer specimens from the AACR Project GENIE.
- Identification and functional annotation of mutations in RAS-MAPK pathway genes (KRAS, NRAS, HRAS, BRAF, MAP2K1, RAF1, PTPN11).
Main Results:
- RAS-MAPK pathway activating mutations were found in KRAS (44%), NRAS (4%), BRAF (10%), and other genes.
- Extended testing identified pathogenic RAS pathway mutations in 56% of cases, compared to 37% with limited KRAS analysis alone.
- Panel next-generation sequencing identified additional driver mutations not covered by current guidelines.
Conclusions:
- Panel next-generation sequencing significantly increases the detection rate of RAS-MAPK pathway mutations in colorectal cancer.
- These findings suggest that broader molecular profiling could optimize treatment selection and prognostic stratification for advanced CRC patients.
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