# TP53 mutation and del(17p)

Source: https://onco.cc/biomarkers/tp53-del17p/  
OnCo record `tp53-del17p` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

TP53 mutation, or deletion of the 17p arm that carries the gene, is the single most common change in cancer and carries a worse outlook almost everywhere. In chronic lymphocytic leukaemia it decides treatment: chemotherapy is avoided and venetoclax's first approval was for del(17p) disease.

## Summary

TP53 status is read by sequencing (mutations in exons 4 to 10) and del(17p) by FISH; in endometrial and other cancers p53 immunohistochemistry (overexpression or complete absence) is the surrogate. Venetoclax (Venclexta) was first approved in 2016 for CLL with 17p deletion as detected by an FDA-approved test, the Vysis CLL FISH Probe Kit being the companion diagnostic; its CLL indications have since broadened to all patients, and guidelines (iwCLL, NCCN) keep TP53 status as the reason to prefer targeted agents over chemoimmunotherapy. In AML and MDS, TP53 mutation defines an adverse-risk group in ELN 2022 and the WHO and ICC 2022 classifications; in endometrial cancer p53-abnormal is one of the four molecular classes.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: TP53 mutation; TP53-mutated; del(17p); 17p deletion; 17p-; TP53 aberration; p53 abnormal; TP53 disruption; TP53mut
- Tags: biomarker; tp53

## Sources

- Venclexta prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b118a40d-6b56-cee3-10f6-ded821a97018
- FDA: List of FDA-Authorized Companion Diagnostic Devices: https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools

## Connected records

- biomarkers: [dMMR (mismatch repair deficiency by IHC)](https://onco.cc/biomarkers/dmmr-ihc/), [IDH1 R132 mutation](https://onco.cc/biomarkers/idh1-r132/), [MYCN amplification](https://onco.cc/biomarkers/mycn-amp/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Endometrial cancer](https://onco.cc/cancers/endometrial/), [Myelodysplastic syndromes / neoplasms (MDS)](https://onco.cc/cancers/mds/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [p53-abnormal endometrial cancer, including uterine serous carcinoma](https://onco.cc/cancers/endometrial-p53-abnormal/), [Relapsed or refractory chronic lymphocytic leukaemia](https://onco.cc/cancers/cll-relapsed/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- drugs: [Venetoclax](https://onco.cc/drugs/venetoclax/)
- terms: [del(17p) / TP53 aberration in CLL](https://onco.cc/terms/del17p-tp53/), [FISH / ISH (in situ hybridisation)](https://onco.cc/terms/fish/), [Li-Fraumeni syndrome (germline TP53)](https://onco.cc/terms/li-fraumeni/), [TP53-mutated (p53-abnormal)](https://onco.cc/terms/tp53-mutated/)
- targets: [TP53](https://onco.cc/targets/tp53/)

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