TP53 mutation and del(17p)

aka TP53 mutation, TP53-mutated, del(17p), 17p deletion, 17p-, TP53 aberration, p53 abnormal, TP53 disruption, TP53mut

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.

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.

Part ofTP53· TP53 All readouts

TP53: what it is and how drugs act on it · animated schematic, not to scale

Target · the protein and the cell it sits on
Drug · antibody, small molecule, cell or radioligand
Effect · signal, damage or kill

In plain words · TP53 is the 'guardian of the genome', broken in half of all cancers. Fixing it directly has so far defeated every attempt, so drugs exploit what its loss makes cancers depend on.

Sequencing No approval threshold

What it means for a patient

A TP53 mutation or 17p deletion usually means the cancer is harder to treat with chemotherapy. In chronic lymphocytic leukaemia it means your team will choose a BTK inhibitor or venetoclax-based treatment instead of chemoimmunotherapy. In leukaemia and womb cancer it places the disease in a higher-risk group that changes how intensively it is treated and followed.

Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.

Scoring rule

A pathogenic TP53 mutation by sequencing, deletion of 17p13 by FISH (the Vysis CLL probe set), or an abnormal p53 immunohistochemistry pattern (strong diffuse nuclear overexpression, complete absence, or cytoplasmic staining) as a surrogate.

“TP53: Deletion chromosome 17p (17p-)”
FDA: List of FDA-Authorized Companion Diagnostic Devices

Thresholds used in approvals

No approval uses this readout as a threshold. It is defined by European LeukemiaNet 2022 recommendations for AML (Döhner et al., Blood 2022): TP53 mutation as adverse risk.

1 historic or withdrawn threshold

Threshold	Drug	Cancer	Regulator	Source
17p deletion by FISH (historic first indication; the CLL indication is now unrestricted)historic The 2016 accelerated approval was for CLL with 17p deletion after at least one prior therapy; the current Venclexta label covers CLL and SLL without a TP53 restriction.	Venetoclax	Chronic lymphocytic leukaemia	FDA	label

Drugs whose label names it

Venetoclax

Companion diagnostics (FDA list)

Device	Maker	Indication and sample	Drug	PMA / 510(k)
Vysis CLL FISH Probe Kit	Abbott Molecular	B-cell Chronic Lymphocytic Leukemia - Peripheral Blood	Venetoclax	P150041 (04/11/2016)

Tests that measure it

Tempus xT and xT CDx FoundationOne CDx FoundationOne Heme Caris MI Profile NeoGenomics NeoTYPE profiles

Trials that name this readout

Matched on the name and aliases of the readout in the title, setting and summary of each trial; a match is a mention, not proof the readout was an entry criterion.