{"entity":{"id":"checkpoint","kind":"term","name":"Checkpoint (two meanings)","aka":["checkpoint","checkpoints","cell-cycle checkpoint","cell cycle checkpoint","cell-cycle checkpoints","checkpoint kinase","checkpoint kinases"],"tldr":"In cancer the word checkpoint means two unrelated things: a brake on immune cells that tumours press and checkpoint inhibitor drugs release, or a gate inside every dividing cell that stops it copying or splitting damaged DNA.","summary":"Immune checkpoints are receptor-ligand pairs such as PD-1 with PD-L1, CTLA-4 with CD80 and CD86, LAG-3, TIM-3 and TIGIT that hold T cells and NK cells back; the drugs are antibodies that block them (or, for co-stimulatory receptors, agonists that press them). Cell-cycle checkpoints are the G1/S, G2/M and spindle assembly gates governed by cyclin D-CDK4/6 and RB, ATR-CHK1-WEE1, and MPS1, BUB1 and Aurora B, with the DNA-damage response behind them; the drugs are small molecules such as palbociclib, olaparib and azenosertib. The two families share a word and nothing else; OnCo keeps a hub for each, with every member, its partner, where it is expressed and the drugs against it.","asOf":"2026-09-24","links":[],"tags":[],"related":["immune-checkpoint","cell-cycle","synthetic-lethality","immuno-oncology"],"cancers":[],"sections":[],"technologies":["checkpoint-inhibitor","cdk46-inhibitor","parp-inhibitor","atr-chk1-inhibitors"],"targets":["pd1","ctla4","lag3","tim3","tigit","btla","vista","klrc1","kir2dl1","cd96","pvrig","pdl1","pdcd1lg2","cd80","cd86","hla-dra","fgl1","lgals9","ceacam1","pvr","nectin2","tnfrsf14","hla-e","cd47","sirpa","cd24","siglec10","lilrb1","lilrb2","cd28","icos","tnfrsf4","cd137","tnfrsf18","cd27","cd40","ido1","tdo2","cd73-adenosine","entpd1","adora2a","b7h3","b7h4","hhla2","tgfb1","il10","cdk4-6","ccnd1","rb1","cdkn2a","atr","chek1","wee1","plk1","atm","chek2","tp53","parp","aurka","aurkb","ttk","bub1"],"drugs":[],"companies":[],"institutions":[],"pathways":["pd1-checkpoint","p53-cell-cycle","mitotic-spindle-checkpoint"],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"provenance":{"editedBy":"OnCo checkpoint map (HGNC REST, UniProt REST, ClinicalTrials.gov v2)","editedOn":"2026-09-24"},"category":"Biology basics"},"route":"/terms/checkpoint/","neighbours":{"term":[{"id":"cell-cycle","kind":"term","name":"Cell cycle","route":"/terms/cell-cycle/"},{"id":"immune-checkpoint","kind":"term","name":"Immune checkpoint","route":"/terms/immune-checkpoint/"},{"id":"immuno-oncology","kind":"term","name":"Immuno-oncology (IO) and checkpoint blockade","route":"/terms/immuno-oncology/"},{"id":"synthetic-lethality","kind":"term","name":"Synthetic lethality","route":"/terms/synthetic-lethality/"}],"technology":[{"id":"atr-chk1-inhibitors","kind":"technology","name":"ATR and CHK1 inhibitors","route":"/technologies/atr-chk1-inhibitors/"},{"id":"cdk46-inhibitor","kind":"technology","name":"CDK4/6 inhibitors","route":"/technologies/cdk46-inhibitor/"},{"id":"checkpoint-inhibitor","kind":"technology","name":"Immune checkpoint inhibitors","route":"/technologies/checkpoint-inhibitor/"},{"id":"parp-inhibitor","kind":"technology","name":"PARP inhibitors","route":"/technologies/parp-inhibitor/"}],"target":[{"id":"adora2a","kind":"target","name":"Adenosine A2A receptor (ADORA2A)","route":"/targets/adora2a/"},{"id":"atm","kind":"target","name":"ATM","route":"/targets/atm/"},{"id":"atr","kind":"target","name":"ATR","route":"/targets/atr/"},{"id":"aurka","kind":"target","name":"AURKA","route":"/targets/aurka/"},{"id":"aurkb","kind":"target","name":"AURKB","route":"/targets/aurkb/"},{"id":"b7h3","kind":"target","name":"B7-H3","route":"/targets/b7h3/"},{"id":"b7h4","kind":"target","name":"B7-H4 (VTCN1)","route":"/targets/b7h4/"},{"id":"btla","kind":"target","name":"BTLA","route":"/targets/btla/"},{"id":"bub1","kind":"target","name":"BUB1","route":"/targets/bub1/"},{"id":"ccnd1","kind":"target","name":"CCND1","route":"/targets/ccnd1/"},{"id":"nectin2","kind":"target","name":"CD112 (nectin-2)","route":"/targets/nectin2/"},{"id":"cd137","kind":"target","name":"CD137 (4-1BB, TNFRSF9)","route":"/targets/cd137/"},{"id":"pvr","kind":"target","name":"CD155 (PVR)","route":"/targets/pvr/"},{"id":"cd24","kind":"target","name":"CD24","route":"/targets/cd24/"},{"id":"cd27","kind":"target","name":"CD27","route":"/targets/cd27/"},{"id":"cd28","kind":"target","name":"CD28","route":"/targets/cd28/"},{"id":"entpd1","kind":"target","name":"CD39 (ENTPD1)","route":"/targets/entpd1/"},{"id":"cd40","kind":"target","name":"CD40","route":"/targets/cd40/"},{"id":"cd47","kind":"target","name":"CD47","route":"/targets/cd47/"},{"id":"cd73-adenosine","kind":"target","name":"CD73 / adenosine axis","route":"/targets/cd73-adenosine/"},{"id":"cd80","kind":"target","name":"CD80 (B7-1)","route":"/targets/cd80/"},{"id":"cd86","kind":"target","name":"CD86 (B7-2)","route":"/targets/cd86/"},{"id":"cd96","kind":"target","name":"CD96","route":"/targets/cd96/"},{"id":"cdk4-6","kind":"target","name":"CDK4/6","route":"/targets/cdk4-6/"},{"id":"cdkn2a","kind":"target","name":"CDKN2A","route":"/targets/cdkn2a/"},{"id":"ceacam1","kind":"target","name":"CEACAM1","route":"/targets/ceacam1/"},{"id":"chek1","kind":"target","name":"CHEK1","route":"/targets/chek1/"},{"id":"chek2","kind":"target","name":"CHEK2","route":"/targets/chek2/"},{"id":"ctla4","kind":"target","name":"CTLA-4","route":"/targets/ctla4/"},{"id":"fgl1","kind":"target","name":"FGL1","route":"/targets/fgl1/"},{"id":"lgals9","kind":"target","name":"Galectin-9 (LGALS9)","route":"/targets/lgals9/"},{"id":"tnfrsf18","kind":"target","name":"GITR (TNFRSF18)","route":"/targets/tnfrsf18/"},{"id":"hhla2","kind":"target","name":"HHLA2 (B7-H7)","route":"/targets/hhla2/"},{"id":"hla-dra","kind":"target","name":"HLA-DRA","route":"/targets/hla-dra/"},{"id":"hla-e","kind":"target","name":"HLA-E","route":"/targets/hla-e/"},{"id":"icos","kind":"target","name":"ICOS","route":"/targets/icos/"},{"id":"ido1","kind":"target","name":"IDO1","route":"/targets/ido1/"},{"id":"il10","kind":"target","name":"Interleukin-10 (IL10)","route":"/targets/il10/"},{"id":"kir2dl1","kind":"target","name":"KIR2DL1 (inhibitory KIR)","route":"/targets/kir2dl1/"},{"id":"lag3","kind":"target","name":"LAG-3","route":"/targets/lag3/"},{"id":"lilrb1","kind":"target","name":"LILRB1 (ILT2)","route":"/targets/lilrb1/"},{"id":"lilrb2","kind":"target","name":"LILRB2 (ILT4)","route":"/targets/lilrb2/"},{"id":"ttk","kind":"target","name":"MPS1 (TTK)","route":"/targets/ttk/"},{"id":"klrc1","kind":"target","name":"NKG2A (KLRC1)","route":"/targets/klrc1/"},{"id":"tnfrsf4","kind":"target","name":"OX40 (TNFRSF4)","route":"/targets/tnfrsf4/"},{"id":"parp","kind":"target","name":"PARP","route":"/targets/parp/"},{"id":"pd1","kind":"target","name":"PD-1","route":"/targets/pd1/"},{"id":"pdl1","kind":"target","name":"PD-L1","route":"/targets/pdl1/"},{"id":"pdcd1lg2","kind":"target","name":"PDCD1LG2","route":"/targets/pdcd1lg2/"},{"id":"plk1","kind":"target","name":"PLK1","route":"/targets/plk1/"},{"id":"pvrig","kind":"target","name":"PVRIG 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checkpoint","route":"/pathways/mitotic-spindle-checkpoint/"},{"id":"p53-cell-cycle","kind":"pathway","name":"p53 / RB / cell-cycle checkpoint","route":"/pathways/p53-cell-cycle/"},{"id":"pd1-checkpoint","kind":"pathway","name":"PD-1 / PD-L1 immune checkpoint & T-cell activation","route":"/pathways/pd1-checkpoint/"}]}}