Interestingly, Kir2.1 regulates cell proliferation and multidrug resistance (MDR) in both NSCLC and SCLC cells (Liu et al., 2015; Wu and Yu, 2019) and also represents a prognostic factor, being overexpressed in primary SCLC and correlating with stage and response to chemotherapy (Liu et al., 2015) (Tables 4, 5). This evidence concerns the gene KCNJ2 and small cell lung carcinoma.