KRAS Mutations in Mediastinal Tumors

Types of Mediastinal Tumors with KRAS Mutations

KRAS mutations are present in approximately 30% of lung adenocarcinomas, which can occur in or extend into the mediastinum, according to the American College of Chest Physicians 1, 2
These mutations are more frequently found in patients with tobacco exposure, although approximately 5% occur in never-smokers, as reported by the Journal of Thoracic Oncology 3
KRAS mutations in lung cancers are most commonly found in codons 12 and 13, less commonly in codon 61, and rarely in codon 146, with a moderate level of evidence 3

KRAS mutations in lung adenocarcinomas are typically mutually exclusive with other driver mutations such as EGFR mutations and ALK rearrangements, with a high level of evidence 3
KRAS mutation-positive tumors are generally resistant to EGFR tyrosine kinase inhibitor (TKI) therapy, as recommended by the American College of Chest Physicians 1, 2
Sequential testing for KRAS can be useful in lung adenocarcinomas, as a positive result greatly diminishes the likelihood of finding other targetable oncogenic alterations, with a moderate level of evidence 3

For lung adenocarcinomas in the mediastinum, molecular testing for KRAS mutations should be considered as part of a comprehensive molecular profiling approach, as recommended by the National Comprehensive Cancer Network 4
The American Society of Clinical Oncology recommends testing for molecular alterations in EGFR, KRAS, and ALK in advanced-stage lung adenocarcinoma, with a high level of evidence 1, 2

KRAS mutations generally confer a worse prognosis in various tumor types, with a moderate level of evidence 5, 6