Our findings indicate that leptin siRNA transfection could decrease the p-JAK1, p-JAK2, and p-STAT3 expression in NSCLC cells, and inhibition of JAK/STAT3 signaling could inhibit cell growth and induce apoptosis in NSCLC A549 cells, indicating the involvement of a JAK/STAT3 pathway in leptin silence-induced proliferation inhibition and apoptosis induction. Here, JAK1 is linked to non-small cell lung carcinoma.