In this study, we performed an in situ immunohistochemical investigation of the status of LKB1 expression in all NSCLC histotypes, beyond and within KRAS mutational status, so as to investigate the LKB1-less phenotype and its possible correlations, as well as the impact of LKB1 status, the emergence of significant correlations, and tumor patients’ prognosis. The gene discussed is STK11; the disease is neoplasm.