PREreview of Loss of erythroblasts in acute myeloid leukemia causes iron redistribution with clinical implications

Major issues

1. Reliance on a single AML mouse model

The study relies almost exclusively on the MLL-AF9 syngeneic AML model. Given the marked biological heterogeneity of AML, validation in additional murine models (e.g., C1498) and human xenograft models (e.g., OCI-AML3 in NSG-SGM3 mice) would considerably strengthen the generalizability and translational relevance of the findings.

2. Lack of pharmacological rescue experiments

Although the authors demonstrate that iron redistribution accompanies AML progression, they do not perform rescue experiments to establish causality. Pharmacological modulation of iron using agents such as Deferoxamine (DFO) or Ferumoxytol (Feraheme) would help determine whether altering iron availability directly influences leukemia progression and iron redistribution.

3. Limited experimental group design

Most experiments compare only Control and AML mice. A more informative design would include additional therapeutic groups such as:

• Control

• AML

• AML + Chemotherapy

• AML + Chemotherapy + DFO

or

• Control

• AML

• AML + DFO

• AML + Chemotherapy

• AML + Chemotherapy + DFO

These groups would clarify whether chemotherapy-induced changes in iron metabolism are mechanistically responsible for hematopoietic recovery and improved survival rather than being secondary consequences of tumor cell death.

4. Limited mechanistic evaluation of leukemia burden

Although survival and iron parameters were extensively analyzed, additional quantitative assessment of leukemia burden (AML cell frequency and absolute cell number in peripheral blood, bone marrow, and spleen) across treatment groups would strengthen the mechanistic interpretation of the observed survival benefit.

Minor issues

1. Bone marrow vascular niche was not evaluated

The study does not investigate whether iron redistribution affects the bone marrow vascular microenvironment. Assessing bone marrow vasculature (e.g., Endomucin-positive area and endothelial cell abundance) would provide additional insight into microenvironmental remodeling during AML progression.

2. Endothelial iron accumulation was not examined

Intracellular iron accumulation was assessed only in AML cells. Measuring intracellular Fe²⁺ in bone marrow endothelial cells would help determine whether iron redistribution also affects the vascular niche.

3. Oxidative stress markers were not assessed

Because excessive iron can promote oxidative damage, evaluation of lipid ROS or ferroptosis-related markers would strengthen the proposed mechanistic link between iron accumulation and tissue dysfunction.

4. Bone marrow cellularity was not quantified

Direct measurement of total bone marrow cellularity would complement the erythroblast analysis and provide a broader assessment of hematopoietic alterations during AML progression.

5. Limited assessment of cell proliferation

The study does not comprehensively evaluate proliferative activity (e.g., Ki67-positive cells) across different bone marrow cell populations. Such analysis could help distinguish whether iron redistribution is associated with altered cellular proliferation.

6. Adaptive immune compartment was not explored

The potential contribution of adaptive immune cells, including CXCR5⁺ lymphocytes (e.g., T follicular helper cells), was not investigated. Furthermore, the use of Rag2⁻/⁻ mice could have helped determine whether adaptive immunity contributes to the observed phenotype, although this falls outside the primary objective of the study.

Competing interests

The author declares that they have no competing interests.

Use of Artificial Intelligence (AI)

The author declares that they used generative AI to come up with new ideas for their review.