# CDKN1B

Source: https://onco.cc/targets/cdkn1b/  
OnCo record `cdkn1b` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CDKN1B (Cyclin-dependent kinase inhibitor 1B) is a gene whose normal job is to hold cell growth in check. The public catalogues list it as a drug target, an oncogene driver, a tumour suppressor and a biomarker, and clinical evidence ties its variants to diagnosis, prognosis or drug response. Tied to Thyroid cancer, Prostate cancer, Breast cancer and 5 more.

## Summary

Important regulator of cell cycle progression. Inhibits the kinase activity of CDK2 bound to cyclin A, but has little inhibitory activity on CDK2 bound to SPDYA. Involved in G1 arrest.

CIViC holds 2 clinical evidence items and 0 assertions across 2 variants, naming Lapatinib, Cisplatin and Fluorouracil. Open Targets scores its association with cancer at 0.81 (direct and indirect evidence; datatypes genetic literature 0.73, affected pathway 0.76, literature 0.99, genetic association 0.75, somatic mutation 0.90, animal model 0.54). IntOGen calls it a driver in 12 cohorts (1 activating, 11 loss-of-function), covering Invasive Breast Carcinoma, Hepatocellular Carcinoma, Plasma Cell Myeloma, Prostate Adenocarcinoma, Small Intestinal Carcinoma.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: cyclin dependent kinase inhibitor 1B; Cyclin-dependent kinase inhibitor 1B; KIP1; P27KIP1
- Tags: cancer-genes-wave
- Symbol: CDKN1B
- Class: tumor-suppressor
- Biology: Important regulator of cell cycle progression. Inhibits the kinase activity of CDK2 bound to cyclin A, but has little inhibitory activity on CDK2 bound to SPDYA. Involved in G1 arrest. Potent inhibitor of cyclin E- and cyclin A-CDK2 complexes. Forms a complex with cyclin type D-CDK4 complexes and is involved in the assembly, stability, and modulation of CCND1-CDK4 complex activation. Acts either as an inhibitor or an activator of cyclin type D-CDK4 complexes depending on its phosphorylation state and/or stoichiometry. Location: Nucleus; Cytoplasm; Endosome (UniProt). Locus 12p13.1 (HGNC).
- Where found: Thyroid cancer: Open Targets association 0.65 with thyroid cancer (MONDO_0002108); Prostate cancer: Open Targets association 0.63 with prostate cancer (MONDO_0008315); IntOGen driver in 4 cohorts (PRAD); Breast cancer: Open Targets association 0.63 with breast cancer (MONDO_0007254); CIViC evidence names this disease; Neuroendocrine tumours: Open Targets association 0.62 with neuroendocrine neoplasm (MONDO_0019496); Head and neck squamous cell carcinoma: CIViC evidence names this disease; Multiple myeloma: IntOGen driver in 2 cohorts (PCM)

## Notes

- Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: CIViC lists 3 therapies; IntOGen calls it an activating (Act) driver in 1 cohort; IntOGen calls it a loss-of-function (LoF) driver in 11 cohorts; CIViC holds 2 clinical evidence items on its variants. Evidence tier "clinical-evidence" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:1785: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:1785
- UniProt P46527: https://www.uniprot.org/uniprotkb/P46527/entry
- NCBI Gene 1027: https://www.ncbi.nlm.nih.gov/gene/1027
- Ensembl ENSG00000111276: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000111276

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/), [IntOGen](https://onco.cc/collections/intogen/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Head and neck squamous cell carcinoma](https://onco.cc/cancers/head-and-neck/), [Hepatocellular carcinoma](https://onco.cc/cancers/hcc/), [Multiple myeloma](https://onco.cc/cancers/multiple-myeloma/), [Neuroendocrine tumours](https://onco.cc/cancers/neuroendocrine/), [Prostate cancer](https://onco.cc/cancers/prostate/), [Small intestine cancer (small bowel adenocarcinoma)](https://onco.cc/cancers/small-bowel/), [Thyroid cancer](https://onco.cc/cancers/thyroid/)
- pathways: [Prostate cancer (KEGG map)](https://onco.cc/pathways/prostate-cancer-signalling/)

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JSON: https://onco.cc/api/v1/entities/cdkn1b.json