Experimental studies in NSCLC cell lines identified effects of IL-9 on cell proliferation or apoptosis suggesting that this cytokine drives tumor growth in NSCLC both in human (Figure 5A) and in murine tumor cells (Figure 7H). Consistently, a previous study showed that IL-9 promoted the proliferation of A549 lung cancer cells (36). The gene discussed is IL9; the disease is lung carcinoma.