Three genetically different subtypes of lung cancer were found, based on somatic copy number variation: “piano”, dominant in never-smokers and rare in smokers, characterized by a low mutational burden, lack of somatic copy number variation, high intra-tumor heterogeneity, long telomeres, frequent KRAS mutations, and slow growth; “mezzo-forte”, enriched with chromosome arm-level amplifications and EGFR mutations; and “forte”, with whole genome doubling. This evidence concerns the gene KRAS and lung cancer.