This is the first study, to our best of knowledge, to show systemic differences in gene expression of major processes involved in carcinogenesis including: cell cycle; DNA repair pathways (MMR, HR, BER, NER); DNA replication; and ErbB, GnRH, VEGF, TGF-β and T cell receptor signalling pathway between LUAD tumour samples in relation to smoking status. Here, GNRH1 is linked to neoplasm.