Gene Expression Profiling of EGFR, FGFR2, PIK3CA, PTEN, SMAD4, STK11, and TP53 in Cell-Free RNA From Exhaled Breath Condensate: Diagnostic, Prognostic, and Therapeutic Implications in Advanced Lung Adenocarcinoma. The gene discussed is EGFR; the disease is lung adenocarcinoma.