LHPP and neoplasm: Recent work has identified lysine-histidine-pyrophosphate phosphatase (LHPP) as a histidine phosphatase and as a tumor suppressor in liver cancer [32], and elevated LHPP expression is associated with improved neuroblastoma patient outcomes (Supplementary Data 2), further supporting a role for the regulation of histidine phosphorylation and for histidine kinase signaling in the pathogenesis of neuroblastoma.