miR-138 expression is downregulated in numerous cancers including glioblastoma [35], and its downregulation can suppress cell proliferation, invasion and migration as a tumour-suppressor gene via targeting of Histone’s H2A variant (H2AX) in cervical cancer cells [36] or via Sry-Related HMG-BOX-4 (SOX4) in ovarian cancer cells [35]. This evidence concerns the gene H2AX and cancer.