HIF1A and glioblastoma: For instance, H19 expression is not affected in wild type p53 cells, whereas it is dramatically upregulated in p53 null cells, revealing that p53 status may govern lncRNA expression under hypoxia [71] Meanwhile, in glioblastoma, the process of HIF-1α binding to the H19 promoter requires SP1 (specific protein 1) to be activated by HIF-1α [72].