CaMKIIδ2 activates HDAC4 and HDAC5 in VSMCs.27 Unlike class I HDAC function in the proliferation of cancer cells, HDAC4 and HDAC5 belong to class IIa HDACs, suggesting that they play a functional role in the proliferation of blood vessels through CaMKIIδ. This evidence concerns the gene HDAC4 and cancer.