Ba/F3 cells with the ZC3HAV1::ABL2 fusion gene are sensitive to STAMP inhibitors, and the SH3 domain is required for the STAMP-mediated in vitro effect. Sensitivity to asciminib (A) and TERN-701 (B) was assessed using the Annexin V-PE and 7-AAD cell death assays in Ba/F3 cells that expressed the empty vector (control), full-length ZC3HAV1::ABL2, and the ZC3HAV1::ABL2 Δ3 (ΖΔ3), ZC3HAV1::ABL2 Δ4 (ΖΔ4) isoforms. (C) The corresponding mean LD₅₀ values are highlighted for each fusion gene. Representative histograms of the intracellular flow cytometry of Ba/F3 cell lines that were treated with 5 μM asciminib (D) or 5 μM TERN-701 (F) and stained with anti-pSTAT5 antibody. The corresponding column graphs of mean fluorescence intensity (MFI) values of pSTAT5 for asciminib (E) and TERN-701 treated cells (G), normalized to untreated control. All experiments were performed in biological replicates (n = 3) and statistical significance was calculated using unpaired Student t tests. Z-A, ZC3HAV1::ABL2; ΖΔ3, ZC3HAV1::ABL2 Δ3; ΖΔ4, ZC3HAV1::ABL2 Δ4. Significance is denoted with asterisks as follows: ∗∗∗∗P < .0001; ∗∗∗P < .001; ∗∗P < .01.