幼年型粒单核细胞白血病 (JMML) 是一种具有骨髓增生异常和骨髓增殖特征的侵袭性儿科恶性肿瘤。治愈性治疗仅限于造血干细胞移植。氟达拉滨联合阿糖胞苷（FLA）和5-阿扎胞苷（AZA）单一疗法是常用的移植前疗法。在这里，我们提出了一种药物筛选策略，使用基于流式细胞术的精准医疗平台来识别潜在的额外治疗漏洞。我们在外周血 (n = 21) 或骨髓 (n = 21) 上筛选了 120 种双药组合和 10 种三药组合 (DC)。 n = 6) 从 27 名患有 JMML 的儿童中提取样本，以鉴定 DC 比 DC 本身的成分更有效地减少白血病细胞。如果与单独使用 DC 最有效成分相比，在 DC 离体治疗中存活下来的白血病细胞较少，则药物效应被称为协同效应。两种耐药组分之间的差异在于效应大小。我们发现 26 个双 DC 和 1 个三 DC 比其组分更有效。分化剂维A酸（TRET；全反式视黄酸）降低了 19/21 (90%) 样本中 FLA 的耐药率（从 15% [2%-61%] 降低至 11% [2%-50%]平均效应大小为 3.8% [0.5%-11%]），AZA 在 19/25 (76%) 样本中（从 69% [34%-100 %] 下降到 47% [17%-83%] ]，平均效应大小为 16% [0.3%-40%]）。在耐药部分中，CD38细胞的平均比例从7%（0.03%-25%；FLA）增加到17%（0.3%-38%；FLA TRET）或从10%（0.2%-31%；AZA）增加至 51%（0.8%-88%；AZA TRET）。TRET 增强了 FLA 和 AZA 在初级 JMML 样品的离体测定中的作用。

Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric malignancy with myelodysplastic and myeloproliferative features. Curative treatment is restricted to hematopoietic stem-cell transplantation. Fludarabine combined with cytarabine (FLA) and 5-azacitidine (AZA) monotherapy are commonly used pre-transplant therapies. Here, we present a drug screening strategy using a flow cytometry-based precision medicine platform to identify potential additional therapeutic vulnerabilities.We screened 120 dual- and 10 triple-drug combinations (DCs) on peripheral blood (n = 21) or bone marrow (n = 6) samples from 27 children with JMML to identify DCs more effectively reducing leukemic cells than the DCs' components on their own. If fewer leukemic cells survived a DC ex vivo treatment compared with that DC's most effective component alone, the drug effect was referred to as cooperative. The difference between the two resistant fractions is the effect size.We identified 26 dual- and one triple-DC more effective than their components. The differentiation agent tretinoin (TRET; all-trans retinoic acid) reduced the resistant fraction of FLA in 19/21 (90%) samples (decrease from 15% [2%-61%] to 11% [2%-50%] with a mean effect size of 3.8% [0.5%-11%]), and of AZA in 19/25 (76%) samples (decrease from 69% [34%-100+%] to 47% [17%-83%] with a mean effect size of 16% [0.3%-40%]). Among the resistant fractions, the mean proportion of CD38+ cells increased from 7% (0.03%-25%; FLA) to 17% (0.3%-38%; FLA + TRET) or from 10% (0.2%-31%; AZA) to 51% (0.8%-88%; AZA + TRET).TRET enhanced the effects of FLA and AZA in ex vivo assays with primary JMML samples.