A high percentage of similarity was found between passaged cell lines of lung cancer and corresponding tumor tissues in terms of morphology (100%), aneuploidy presence (100%), immunohistochemical expression of human epidermal growth factor (EGF) receptor-2 (HER2) (100%), and p53 protein (100%), loss of heterozygosity in 13 analyzed chromosomal regions (97%), mutations in TP53 genes (67%), and transcription factor KRAS (100%). The gene discussed is ERBB2; the disease is neoplasm.