miR-7 expression was found to be decreased in glioblastoma, inhibiting the invasion and metastasis of primary glioblastoma lines, whereas miR-26 enhances glioblastoma cancer development in vitro and in vivo by attempting to target numerous tumor suppressor genes, including RB Transcriptional Co-repressor 1 (RB1) and Phosphatase and tensin homolog (PTEN) (140, 141). The gene discussed is RB1; the disease is glioblastoma.