KRAS and lung carcinoma: KRAS mutations are heterogeneous in their frequency and spectrum in lung cancer and mainly show mutations in codons-12 (89%), 13 (9%), and 61 (1%) [86](Fig. 2).KRAS mutations are categorized into; transitions (a purine-purine, or a pyrimidine-pyrimidine substitution) and transversions (a pyrimidine-purine, or a purine-pyrimidine substitution) [43].