LncRNA NKX2‐1‐AS1 promotes tumor progression and angiogenesis via upregulation of SERPINE1 expression and activation of the VEGFR‐2 signaling pathway in gastric cancer oleh Fei Teng, Ju‐Xiang Zhang, Yi Chen, Xiao‐Dong Shen, Chang Su, Yan‐Jiao Guo, Pu‐Hua Wang, Chen‐cheng Shi, Ming Lei, Yi‐Ou Cao, Shao‐Qun Liu