An EGFR-mutation signature reveals features of the EGFR-dependent phenotype and identifies MACC1 as an EGFR-associated regulator of MET.

EGFR-mutated non-small cell lung cancers bear hallmarks including sensitivity to EGFR inhibitors, and low proliferation, and increased MET. However, the biology of EGFR dependence is still poorly understood. Using a training cohort of chemo-naive lung adenocarcinomas, we have developed a 72-gene signature that predicts (i) EGFR mutation status in four independent datasets; (ii) sensitivity to erlotinib in vitro; and (iii) improved survival, even in the wild-type EGFR subgroup. The signature includes differences associated with enhanced receptor tyrosine kinase (RTK) signaling, such as increased expression of endocytosis-related genes, decreased phosphatase levels, decreased expression of proliferation-related genes, increased folate receptor-1 (FOLR1) (a determinant of pemetrexed response), and higher levels of MACC1 (which we identify as a regulator of MET in EGFR-mutant NSCLC). Those observations provide evidence that the EGFR-mutant phenotype is associated with alterations in the cellular machinery that links the EGFR and MET pathways and create a permissive environment for RTK signaling.

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