CDK4 and lung cancer: With 269 novel interactions, OncoPPi greatly expands the landscape of interactions among this selected set of lung cancer genes (Fig. 1d, Supplementary Fig. 2) and defines interactions with potential significance for cancer PPI target discovery, such as CDK4/STK11, LATS2/RASSF1 and MYC/NSD3 (WHSC1L1).