CASP9 and neoplasm: Data from pericytes in the tumor environment show that RGS5 upregulation in pericytes promotes apoptotic cell death due to the inhibition of Gαi/q. This leads to reduced phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), resulting in an induced activation of caspase-9 and caspase-3 in the tumor microenvironment.