In addition, accumulating evidence shows that several lncRNAs may have a potential role in regulating smad4, for example, lncRNA PCAT7 in prostate cancer cells (Lang et al., 2020), lncRNA 9884 in renal inflammatory cells (Zhang et al., 2019), LINP1 in lung cancer cells (Zhang et al., 2018) and LIN-LET in bladder cancer cells (Zhuang et al., 2017). Here, SMAD4 is linked to lung cancer.