Saida Rahmani, Abdessamad Hachmi, Rajae Taibi, Fatima Bouhtit, Noureddine Boukhatem, Mohammad Fayyad-Kazan, Abdelilah Berhili, Rachid Seddik, Hussein Fayyad-Kazan, Makram Merimi
Acute myeloid leukemia (AML) remains genetically and clinically heterogeneous, and current cytogenetic risk categories do not fully capture biologic diversity or therapeutic vulnerability. We investigated whether a simple THBS1/VEGFA transcriptional ratio could define molecularly distinct AML subsets with prognostic and therapeutic relevance. The ratio was calculated as log₂(TPM_THBS1 + 1) - log₂(TPM_VEGFA + 1) and evaluated in the TCGA-LAML cohort (n = 132), with validation in BeatAML and outcome-independent external validation in GSE37642. Associations with overall survival, cytogenetic risk, leukemia-associated transcriptional programs, and microenvironmental features were assessed using differential expression, pathway enrichment, protein-protein interaction, Gene Ontology, and immune/stromal inference analyses, together with ex vivo drug-sensitivity profiling in the validation cohort. The THBS1/VEGFA ratio stratified overall survival more strongly than THBS1 or VEGFA alone and improved prognostic resolution within cytogenetic risk groups. HIGH-TRatio AML was characterized by an immune-associated molecular state marked by inflammatory signaling, myeloid-skewed immunomodulatory features, and extracellular matrix/microenvironmental remodeling, whereas LOW-TRatio AML showed a metabolically stressed program enriched for MYC targets, unfolded protein response, DNA repair, and proteostasis-related pathways. These transcriptional states were reproducible across cohorts and supported by compact, directionally consistent gene sets. Exploratory drug-sensitivity analysis suggested trends toward broader sensitivity among LOW-TRatio samples and relative resistance to several targeted agents among HIGH-TRatio samples, including VEGFR/multikinase inhibitors. These findings identify the THBS1/VEGFA ratio as a biologically interpretable transcriptomic marker that refines AML stratification beyond cytogenetics and captures clinically relevant molecular heterogeneity.