EGFR and adenocarcinoma: EGFR mutations, initially described in 2004 by Lynch et al., cause the aberrant activation of a transmembrane tyrosine kinase and are present in 15% of NSCLC cases in our population (in Asian populations, the presence of EGFR mutations has been described in >50% of NSCLC cases), being more frequent in adenocarcinomas than in squamous cell carcinomas, in people with little or no smoking and in women [47,48].