RB1 encodes the retinoblastoma protein, a tumor suppressor and negative regulator of the cell cycle (Figure 2).[18] The loss of RB1 protein expression has been linked to poor survival and may prognosticate a decreased response to kinase inhibitors.[18] RB1 mutations have been reported sporadically in HCC.[7] At the time of referral to the CCTT the patient had metastatic disease to the right pterygoid fossa and liver and his clinical condition precluded experimental therapy. The gene discussed is RB1; the disease is metastatic neoplasm.