Mutations in the KEAP1-NFE2L2 Pathway Define a Molecular Subset of Rapidly Progressing Lung Adenocarcinoma.

INTRODUCTION

Molecular characterization studies revealed recurrent kelch like ECH associated protein 1 gene (KEAP1)/nuclear factor, erythroid 2 like 2 gene (NFE2L2) alterations in NSCLC. These genes encode two interacting proteins (a stress response pathway [SRP]) that mediate a cytoprotective response to oxidative stress and xenobiotics. Nevertheless, whether KEAP1/NFE2L2 mutations have an impact on clinical outcomes is unclear.

METHODS

We performed amplicon-based next-generation sequencing to characterize the SRP in patients with metastatic NSCLC (Regina Elena National Cancer Institute cohort [n = 88]) treated with first-line chemotherapy. Mutations in the DNA damage response (tumor protein p53 gene [TP53], ATM serine/threonine kinase gene [ATM], and ATR serine/threonine kinase gene [ATR]) were concomitantly analyzed. In lung adenocarcinoma (LAC), we also determined the expression of phosphorylated ataxia telangiectasia mutated kinase and ataxia telangiectasia and Rad3-related protein. Two independent cohorts (the Memorial Sloan Kettering Cancer Center cohort and The Cancer Genome Atlas cohort) with data from approximately 1400 patients with advanced LAC were used to assess the reproducibility of the results.

RESULTS

In the Regina Elena National Cancer Institute cohort, patients whose tumors carried mutations in the KEAP1/NFE2L2 pathway had significantly shorter progression-free survival and overall survival than their wild-type counterparts did (log-rank p = 0.006 and p = 0.018, respectively). This association was driven by LAC in which KEAP1/NFE2L2 mutations were overrepresented in fast progressors and associated with an increased risk of disease progression and death. LACs carrying KEAP1/NFE2L2 mutations were characterized by elevated expression of phosphorylated ataxia telangiectasia mutated (pATM) kinase and ataxia telangiectasia and Rad3-related (pATR) protein in association with a pattern of mutual exclusivity with TP53 alterations. The relationship between KEAP1/NFE2L2 mutations and shorter survival was validated in the Memorial Sloan Kettering Cancer Center cohort (n = 1256) (log-rank p < 0.001) and in The Cancer Genome Atlas cohort (n = 162) (log-rank p = 0.039).

CONCLUSION

These findings suggest that a mutant SRP represents a negative prognostic/predictive factor in metastatic LAC and that KEAP1/NFE2L2 mutations may define a molecular subtype of chemotherapy-resistant and rapidly progressing LAC.