EGFR and non-small cell lung carcinoma: Gene expression profiling of crizotinib-resistant versus crizotinib-naive NSCLC tumor samples using RNA sequencing followed by single-sample gene set enrichment analysis (ssGSEA) has identified EGFR and HER2 (members of the HER receptor family) signatures as two of the most enriched gene expression marks in resistant tumors [174].