| Domain | Key facts | Key numbers | Evidence type | Source / DOI / NCT |
|---|---|---|---|---|
| Definition / classification | Mixed phenotype acute leukemia (MPAL; MONDO:0020743) is an acute leukemia of ambiguous lineage with blasts showing myeloid plus B- or T-lineage features. WHO/ICC-based criteria require lineage-defining markers; B/myeloid is the most common subtype. MPAL with AML-defining recurrent abnormalities such as t(8;21), inv(16), or t(15;17) is excluded from the MPAL category. | ALAL/MPAL represents ~2–3% of acute leukemias; B/myeloid ~67% of MPAL (pqac-00000007, pqac-00000006) | Classification review + cohort synthesis | Haematologica 2025 doi:10.3324/haematol.2025.287793; Hematology 2024 doi:10.1182/hematology.2024000554 (pqac-00000007, pqac-00000006) |
| Epidemiology | MPAL is rare in both children and adults. SEER-based incidence data cited in recent review support extreme rarity; pediatric cohorts show male predominance and substantial Hispanic representation in US series. | Incidence 0.35 per 1,000,000 person-years; pediatric MRD cohort: n=94, 66% male, 55% Hispanic, 46% age <10 years (pqac-00000007, pqac-00000015) | Registry/review + multicenter pediatric cohort | Haematologica 2025 doi:10.3324/haematol.2025.287793; Leukemia 2020 doi:10.1038/s41375-020-0741-0 (pqac-00000007, pqac-00000015) |
| Molecular subtypes | Recurrent genomic lesions include BCR::ABL1, KMT2A rearrangements, ZNF384 rearrangements, and BCL11B activation; RUNX1 mutations are enriched. B/myeloid and T/myeloid MPAL have different mutational and methylation patterns. | BCR::ABL1 in 15–20%; KMT2A-r ~10%; ZNF384-r up to 50% of pediatric B/myeloid MPAL; BCL11B activation 10–15% overall and up to one-third of T/myeloid MPAL (pqac-00000003, pqac-00000006) | Genomic cohort + review | Nature 2018 doi:10.1038/s41586-018-0436-0; Nature Communications 2018 doi:10.1038/s41467-018-04924-z; Hematology 2024 doi:10.1182/hematology.2024000554 (pqac-00000003, pqac-00000006) |
| Diagnostics | Diagnosis integrates morphology, multiparameter flow cytometry, cytogenetics/FISH, and NGS/RNA fusion testing. Pediatric centrally reviewed cases were predominantly B/myeloid, MPO-positive and CD19-positive. Differential diagnosis includes secondary AML with mixed phenotype, which behaves differently from true MPAL. | Pediatric cohort: 89% B/myeloid, 94% MPO+, 90% CD19+; ALL-directed induction CR 96.6% in MPAL vs 14.3% in secondary AML with mixed phenotype in cited comparative series (pqac-00000015, pqac-00000001) | Multicenter cohort + comparative clinicopathologic study | Leukemia 2020 doi:10.1038/s41375-020-0741-0; Haematologica 2025 doi:10.3324/haematol.2025.287793 (pqac-00000015, pqac-00000001) |
| First-line therapy | Current expert consensus favors ALL-type induction for most MPAL, with TKI added for Philadelphia-positive/BCR::ABL1-positive disease. Pediatric data support ALL therapy without routine upfront HSCT in many cases. | Meta-analytic effect cited: ALL-based therapy superior for CR and OS (OR 0.33 and 0.45 vs AML-based, direction favoring ALL); pediatric 5-year EFS 80%±4% with ALL-type vs 36%±7.2% with AML-type; HyperCVAD CR/CRi 84% in adults (pqac-00000002, pqac-00000005) | Review/meta-analysis + pediatric cohort | Haematologica 2025 doi:10.3324/haematol.2025.287793; Cancer 2020 doi:10.1002/cncr.32552 (pqac-00000002, pqac-00000005) |
| MRD / HSCT | MRD is a major prognostic marker. In children, early MRD negativity predicts better survival and may support avoiding HSCT in CR1; in adults, HSCT is often considered for high-risk disease, persistent MRD, or adverse genetics. | 70% EOI MRD-negative after ALL induction; EOI MRD positivity HR 6.00 for 5-year EFS and HR 9.57 for OS; adult transplant registry: 3-year relapse 31.4%, NRM 22.1%, LFS 46.5%, OS 56.3%; MRD-negative adults after induction had 75.8% vs 45.2% 5-year OS in one study (pqac-00000010, pqac-00000004) | Multicenter pediatric cohort + adult transplant registry/review | Leukemia 2020 doi:10.1038/s41375-020-0741-0; Haematologica 2025 doi:10.3324/haematol.2025.287793 (pqac-00000010, pqac-00000004) |
| Prognosis | MPAL overall has poorer outcomes than standard-risk ALL and many AML subsets, but prognosis varies by age, genetics, MRD, and therapy. KMT2A-rearranged and complex-karyotype disease are adverse; Ph+ disease outcomes improve with TKI-based therapy. | Pediatric COG cohort: 5-year EFS 72%±8%, OS 77%±7%; ALL-only/no HSCT subgroup EFS 75%±13%, OS 84%±11%; Ph+ MPAL median OS 53.6 months, 5-year OS 49%; AUL median OS 1.4 months; KMT2A-r associated with ~10-fold increased mortality risk in cited review (pqac-00000005, pqac-00000002) | Pediatric cohort + review synthesis | Cancer 2020 doi:10.1002/cncr.32552; Haematologica 2025 doi:10.3324/haematol.2025.287793 (pqac-00000005, pqac-00000002) |
| Recent single-cell developments | Recent 2023–2024 single-cell studies show MPAL is highly heterogeneous yet shares stem-like programs. Pediatric scRNA-seq distinguished B/myeloid from T/myeloid MPAL; adult multiomic single-cell profiling identified a stem-like transcriptional state and a prognostic MPAL95 score. | Pediatric scRNA-seq: >40,000 cells from 9 cases; 44% relapsed/refractory overall in that cohort; adult multiomic study: 14 newly diagnosed cases; MPAL95 predicted survival in an independent cohort (pqac-00000012, pqac-00000016) | Primary single-cell / multiomic studies | Genome Medicine 2023 doi:10.1186/s13073-023-01241-z; Nature Communications 2024 doi:10.1038/s41467-024-52317-2 (pqac-00000012, pqac-00000016) |
| Experimental / translational trials | Active/modern trials are testing lower-intensity or targeted strategies, especially for adults or newly diagnosed disease: blinatumomab for CD19+ MPAL, venetoclax/azacitidine-based combinations, and other investigational regimens. Preclinical ZNF384 models support FLT3 inhibition. | NCT07222579 recruiting (subcutaneous blinatumomab; adult CD19+ MPAL; planned enrollment 78); NCT07517510 phase 2 enrolling by invitation (homoharringtonine + venetoclax + azacitidine; enrollment 40); NCT07573670 phase 2 not yet recruiting (BCL-2 inhibitor + azacitidine; enrollment 52); ZNF384 study tested 71 leukemia samples plus 15 MPAL samples and showed gilteritinib activity in PDX models (pqac-00000021, pqac-00000018, pqac-00000020, pqac-00000017) | Clinical trials + preclinical functional study | ClinicalTrials.gov NCT07222579, NCT07517510, NCT07573670; Blood Cancer Discovery 2022 doi:10.1158/2643-3230.bcd-21-0163 (pqac-00000021, pqac-00000018, pqac-00000020, pqac-00000017) |


*Table: Concise knowledge-base summary table for mixed phenotype acute leukemia covering classification, epidemiology, molecular features, diagnostics, treatment, prognosis, and recent translational developments. It highlights key numbers and cites the available evidence contexts and trial identifiers for rapid downstream curation.*