EGFR and neoplasm: A recent review by the National Institute for Health, identified three molecular subtypes of cancer in non-smokers: piano, a slow growing subtype associated with progenitor cells with few mutations, mezzo-forte, harbouring EGFR-related mutations which grew quicker than the piano group, and forte, which had genomic changes similar to those who smoked, demonstrating that there is heterogeneity in the pathogenesis of tumours in this population of patients.