Hepatocyte odd protein shuttling (HOPS), whose over-expression results in cell cycle arrest in G0/G1 and whose knockdown causes centrosome hyper-amplification, interacts with NPM and p19ARF, functioning as a bridging protein between NPM and p19ARF, which are mutually antagonistic with respect to tumor cell proliferation [212]. This evidence concerns the gene CDKN2A and neoplasm.