HNF4A and hepatocellular carcinoma: In silico analysis of protein-protein interaction datasets using the “Harmonizome” database [44] revealed a list of 34 PDE6D-interacting proteins including KRAS, HRAS, and several transcription factors that are known to be involved in HCC progression such as E2F1 [45,46] and HNF4A [47,48] (Figure S4A).