GRK2 and prostate neoplasm: GRK2 protein levels have been differentially upregulated in tissue samples of patients with granulose cell tumors, with differentiated thyroid carcinoma [49, 50] or downregulated in a subgroup of prostate tumors [51], which suggests that altered GRK2 expression in specific tumor cells may affect migration in response to particular stimuli and plays a critical role in basic cellular functions such as cell proliferation, differentiation or migration during development.