ITM2B and urinary bladder carcinoma: In addition to SUCLA2, there are some more genes neighboring RB1 locating even closer to RB1. Lee et al. demonstrated that among such genes, loss of integral membrane protein 2B (ITM2B), chromosomal condensation 1-llike (CHC1L) and purinergic receptor P2Y G protein-coupled protein 5 (P2RY5) function may contribute to enhance tumor promotion in RB1-deficient bladder cancer [102].