Integrated prognostic model for TP53‑mutated myeloid neoplasms across all myeloid neoplasm subtypes Free

Background:TP53-mutated myeloid neoplasms (MNs) represent one of the most lethal subgroups of blood cancers. The World Health Organization (WHO-5) recognize TP53-mutated (TP53^mut) myelodysplastic syndrome (MDS) and International Consensus Classification (ICC) recognize TP53^mut MDS and acute myeloid leukaemia (AML) as distinct disease entities, acknowledging their dismal prognosis and the urgent need for novel therapeutic strategies. However, key discrepancies exist between the classifications, creating uncertainty in diagnosis, influencing therapeutic decisions, and complicating clinical trial enrolment for patients with uniformly poor survival. Importantly, neither classifications included TP53-mutated myelofibrosis (MF), other myeloproliferative neoplasms (MPN), and MDS/MPN overlap syndromes, despite growing evidence that these cases carry similar adverse outcomes. To address these critical gaps, we conducted a comprehensive analysis across the full spectrum of TP53-mutated MN.

Methods: We included TP53^mut cases with variant allele frequency (VAF ≥2%) of AML, MDS, MDS/MPN overlap, myelofibrosis and other MPN managed at the Mayo clinic (Rochester, USA) and Local Health Network in South Australia (Australia). Cases were classified according to the revised 4^th edition WHO classification (WHO-4R).

Biallelic TP53 loss was defined as: (i) ≥2 mutations with VAF ≥2%; (ii) single TP53^mut with VAF ≥2% plus 17p loss on karyotype, FISH, or SNP array; or (iii) single TP53^mut with VAF ≥50% with or without 17p loss. Monoallelic loss was defined as a single TP53^mut with VAF <50% without 17p loss or copy neutral loss of heterozygosity.

The primary endpoint was overall survival (OS) from diagnosis, censored at allogeneic transplantation. Conditional inference tree analysis was performed to define the effect of individual predictors on OS.

Results: We identified 853 TP53^mutMN cases including WHO-4R-defined AML (BM/PB blasts ≥20%, n=314; 36.8%), MDS with excess blasts-2 (EB-2; BM 10–19% or PB 5–19%, n=129; 15.1%), MDS-EB-1 (BM 5–9% or PB 2–4%, n=100; 11.7%), and MDS with low blasts (LB; BM <5% and PB <1%, n=228; 26.7%). MF included chronic phase (MF-CP, n=48; 5.6%), accelerated phase (MF-AP, n=7; 0.8%), and blast phase (MF-BP, n=17; 2.0%). Additional cases comprised other MPN-chronic phase (n=3, 0.4%) and MDS/MPN overlap syndromes (n=7, 0.8%).

Of 848 evaluable TP53^mut MN, 616 (72.6%) harbored biallelic TP53 loss and 232 (27.4%) had monoallelic loss, with 42.4% (n=98) of monoallelic cases harboring a complex karyotype (CK). Biallelic loss was highly prevalent in AML (83.1%), MDS (70.4%), and MDS/MPN overlap (71.4%), but was less frequent in cases with MPN (33.3%) and MF-chronic phase (25.0%). Across the spectrum, the frequency of biallelic loss increased stepwise with disease progression, rising from MDS-LB (62.8%) to MDS-EB1 (76.0%), MDS-EB2 (79.5%), AML (83.1%), and MF-AP/BP (79.2%) (P<0.0001).

In multivariable analysis, WHO-4R category, TP53^mut VAF, biallelic loss and CK were independent predictors of poor survival in TP53^mut MN. Conditional inference tree analysis stratified the cohort into seven prognostic groups with distinct median OS: (1) AML, MF-BP/AP, and MDS/MPN overlap regardless of mono/biallelic and CK status (n=335, 39.7%; median OS 4.0 months); (2) MDS-EB1/EB2 with biallelic loss or monoallelic plus CK (n=212, 25.1%; 7.2 months); (3) MDS-LB, MF-CP and MPN with CK (n=156, 18.5%, OS 10.2 months); (4) biallelic MDS-LB (n=28, 3.3%; OS 15.6 months), (5) monoallelic MDS-EB1/EB2 without CK (n=20, 2.4%; OS 26.2 months), (6) monoallelic MDS-LB without CK (n=57, 6.7%; OS 33.4 months), and (7) MF-CP and other MPN without CK (n=36, 4.3%; OS 37.0 months). This analysis defines a clear stepwise risk gradient, identifying subsets with extremely poor prognosis versus a relatively indolent disease.

Conclusions: This is the first study to evaluate the prognostic impact of TP53^mut MN across the entire MN spectrum, providing a framework for future refinement of TP53-driven disease classification. Key findings include: (i) MF-AP/BP and MDS/MPN overlap exhibit survival outcomes as dismal as AML, irrespective of the TP53 allele status; and (ii) complex karyotype is a surrogate for “biallelic equivalent”, refining risk interpretation in monoallelic cases. Overall, our study defines seven prognostic subgroups spanning all TP53^mut MN, offering a foundation for risk-adapted clinical trial design and future classification updates.