In the context of epigenetic initiation, different histological types of lung cancer each exhibit distinct genomic characteristics, such as RB1 and MYC alterations in SCLC, NFE2L2, TP63 and NOTCH1 variations in LUSC, and EGFR, KRAS and ERBB2 variations in LUAD. The gene discussed is KRAS; the disease is lung cancer.