NPTN-IT1 and lung adenocarcinoma: NPTN-IT1 is a recently identified lncRNA, located on chromosome 15q24.1, which has a low expression level in tumor tissues and can inhibit the growth and metastasis of hepatocellular carcinoma, lung adenocarcinoma (Yang et al., 2013; Liu et al., 2016), nasopharyngeal carcinoma and cervical cancer (Jiang et al., 2015; Sun et al., 2015).