Functional annotation separates good and poor prognosis in monoallelic TP53 myelodysplasia

Design

Retrospective analysis of two independent patient cohorts

Population

4,505 patients with myelodysplastic neoplasms (271 monoallelic TP53, 499 multi-hit)

Primary outcome

Leukaemia-free survival by TP53 allelic state and functional phenotype score

Effect

Single-mutation median LFS 12.6 vs 43.3 months for high vs low score (p<0.001)

Researchers analysed pretreatment samples from 4,505 patients with myelodysplastic neoplasms from two independent cohorts, including 271 with a single TP53 mutation and 499 with multi-hit TP53 disease.

Median leukaemia-free survival was 37.2 months with wild-type TP53, 19.2 with a single mutation and 7.8 with multi-hit disease (p<0.001). Within the single-mutation group, a previously published functional phenotype score, derived from saturation mutagenesis screens, divided patients: high score (7 or more) 12.6 months against 43.3 for low score (p<0.001), especially in IPSS-R and IPSS-M low-risk cases.

Combining score with variant allele fraction refined it. A high score with VAF of 22% or more gave 9.2 months, comparable with multi-hit disease (7.8 months, p=0.3), while a low score with VAF below 22% gave 44.7 months, close to wild-type (37.2 months, p=0.8). The reporting pathologist's TP53 line may soon need to carry more than allele count.

• Report allelic state and variant allele fraction for every TP53 mutation in MDS.
• A single mutation is not one entity: function and burden changed median survival severalfold.
• Variant-level annotation matters most in patients who look low risk on IPSS-R or IPSS-M.
• Agree with haematology which functional score, if any, your laboratory will cite.

Why it matters

It challenges the idea that all single TP53 mutations carry the same risk.

Don't overread it

Cut-offs were derived in these cohorts and the score is not yet part of standard classification.

The statistics, in plain English

Median survival is the time at which half of patients have had the event, so a difference from 12.6 to 43.3 months is large. Cut-offs such as a score of 7 or VAF of 22% were chosen in these data, so they need confirming elsewhere before being used as thresholds.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.