HHEX and prostate cancer: CK2 activity is often elevated in cancer cells and CK2 inhibition has been proposed as a novel treatment for prostate cancer.19 To determine whether the inhibition of CK2 activity alters the proliferation of PNT2-C2 cells and to investigate whether any effects of CK2 inhibition are dependent on changes in PRH phosphorylation, we treated control and PNT2-C2 PRH knockdown cells with the CK2 inhibitor TBB.