BRD4 and Miyoshi myopathy: Two BRD4 inhibitors, JQ1 and CPI -203, reduced both MYC and PVT1 in MM cell lines, but the MYC inhibitor did not reduce PVT1 expression, suggesting that PVT1 expression is not controlled by MYC, but that both genes were regulated by BRD4. The reduction of MYC mRNA by PVT1 knockdown indicated that PVT1 regulates MYC expression at the transcriptional level.