H19 and glioblastoma: Our data further suggest that the expression of H19 is significantly up-regulated in the frontal cortex of male PAE mice with opposing changes in the developmental- and brain region specific- expression to that of circHomer1. Importantly, knockdown of H19 in human glioblastoma cell lines resulted in a robust up-regulation of circHomer1 but not linear HOMER1 mRNA.