GLUT1 is a membrane-bound facilitative glucose transporter primarily responsible for cellular glucose uptake, accounting for approximately 5% of red blood cell membrane mass, and is also a key transporter for L-dehydroascorbic acid in erythroid cells.
During erythropoiesis, GLUT1 protein expression is detectable at the basophilic erythroblast stage and increases with further maturation. Recent studies have found that GLUT1 protein levels are low in proerythroblasts and significantly increase as erythroid precursors mature into late erythroblasts, indicating that GLUT1 may be a well-characterized IHC marker for erythroid differentiation.
Previously established IHC markers for erythroid differentiation, such as E-Cadherin, each have their unique advantages and limitations. GLUT1 will be a practical addition to the reliable set of erythroid markers. Therefore, this study evaluates the utility of GLUT1 IHC as a clinical marker for identifying erythroid differentiation in hematopoietic tissues, including neoplastic proliferations.
Selected benign and neoplastic bone marrow biopsy specimens with varying proportions of erythroid precursors (n=46, including 36 leukemia cases) were used. GLUT1 IHC staining was performed on erythroid precursors, non-erythroid hematopoietic cells, and blasts for each case. GATA1/GLUT1 double staining was performed on one patient to confirm GLUT1 co-expression on early erythroid precursors. Staining results were compared with other erythroid markers, including glycophorin C.
GLUT1 IHC staining was performed on 4 patients with regenerative erythroid hyperplasia and 6 patients with benign or post-treatment residual disease with varying numbers of erythroid clusters. Results showed strong membrane and cytoplasmic staining in early, intermediate, and late erythroid precursors in all 10 patients (Figure 1; individual erythroid precursors were identified as early, intermediate, or late based on clustering, cell size, and nuclear morphology shown by IHC), with slightly weaker staining in early erythroid precursors. Mature red blood cells in biopsy specimens also showed strong GLUT1 positivity. This indicates that GLUT1 IHC staining is specific for the erythroid lineage, but weak cytoplasmic staining was observed in a subset of megakaryocytes (Figure 1).
Notably, the staining pattern of the aforementioned erythroid precursors was also recognized in all leukemias with hematopoietic factors (n = 29).
GLUT1/GATA1 double staining on benign bone marrow from a patient with erythroid hyperplasia confirmed strong membrane and cytoplasmic co-expression of GLUT1, while GATA1-negative myeloblasts and immature granulocytes were GLUT1-negative (Table 1).
Figure 1. GLUT1 expression pattern in benign bone marrow: GLUT1 shows strong cytoplasmic and membrane staining in erythroid precursors, variable cytoplasmic staining in megakaryocytes (top right), and GLUT1-negative background bone marrow cells (×100).
Table 1. Summary of GLUT1 staining in non-neoplastic hematopoietic tissues
GLUT1 IHC staining was performed on various bone marrow biopsy specimens from leukemias, including myeloid and lymphoid lineages (Table 2). It was found that GLUT1 showed strong to moderate cytoplasmic and membrane staining in malignant proerythroblasts from 6 cases of pure erythroid leukemia and 2 cases of therapy-related acute myeloid leukemia (t-AML) with blasts showing erythroid differentiation (Figures 2A and 2B). In contrast, malignant blasts from acute leukemias without erythroid differentiation were GLUT1-negative (Figure 2C). This included cases with a wide range of differentiation: myeloid, promyelocytic, monocytic, megakaryocytic, and minimally differentiated, among others.
GLUT1 staining showed weak to moderate cytoplasmic/membrane granular staining in lymphoblasts from 4 out of 5 cases of B-lymphoblastic leukemia (B-ALL) (3 weak, 1 moderate) (Figure 2D). Lymphoblasts from another case of T-cell acute lymphoblastic leukemia were GLUT1-negative.
All cases of myelodysplastic syndrome (MDS) and therapy-related MDS (t-MDS) showed strong staining in erythroid precursors, while mononuclear cells consistent with myeloblast morphology showed no staining. Two cases of myelodysplastic syndrome with excess blasts-2 (MDS-EB-2) had a significant erythroid hyperplastic component, with GLUT1 staining positive, spatially matching clusters of glycophorin C-positive cells, indicating that these GLUT1-positive cells were erythroid precursors.
Figure 2. GLUT1 IHC staining in leukemia. A: Pure erythroid leukemia with strong GLUT1 cytoplasmic and membrane positivity (×100); B: Strong GLUT1 staining in malignant blasts with erythroid differentiation and erythroid precursors in t-AML (×100); C: A case of minimally differentiated acute myeloid leukemia showing GLUT1-positive residual early erythroid precursors and GLUT1-negative malignant blasts; D: B-lymphoblastic leukemia with weak to moderate granular GLUT1 staining, GLUT1-negative lymphocytes in reactive lymphoid aggregates at the top of the field, and scattered red blood cells and late erythroid cells GLUT1-positive in neoplastic lymphoblasts (×100).
Table 2. GLUT1 staining in leukemia cells
Glycophorin C testing was performed on 9 cases of benign/reactive erythroid hyperplasia, 6 cases of acute myeloid leukemia (AML; non-pure erythroid leukemia), 1 case of t-AML with blasts showing erythroid differentiation, 1 case of t-AML with myelomonocytic differentiation, 1 case of MDS-EB-2, and 1 case of MDS. In benign/reactive erythroid hyperplasia, the staining pattern of glycophorin C was nearly identical to GLUT1, with strong cytoplasmic/membrane staining in erythroid precursors (positive cells were consistent spatially and in total number, Figure 3), but glycophorin C staining was weaker in proerythroblasts (Figure 3B). Similar to GLUT1, glycophorin C showed no staining in malignant blasts in undifferentiated AML and t-AML, but in 2 AML cases, glycophorin C staining in background proerythroblasts and early erythroid precursors was noticeably darker than GLUT1.
Figure 3. Erythroid clusters and potential PCM1-JAK2 fusion in a patient with myeloproliferative neoplasm. A: Large clusters of early erythroid precursors on H&E (×200); B: Early erythroid precursors show moderate-weak glycophorin C staining (×200); C-D: GLUT1 shows uniformly strong staining in all erythroid precursors at ×100 and ×200.
E-Cadherin staining was performed on 2 AML patients without erythroid differentiation. Similar to GLUT1, E-Cadherin expression was negative in malignant blasts.
Comparative results indicate that GLUT1 has excellent sensitivity and specificity for leukemia, comparable to markers like E-Cadherin.
IHC markers for erythroid differentiation are important tools for confirming erythroid lineage. This is crucial in the diagnosis of bone marrow dysplasia with left-shifted erythroid precursor hyperplasia, as morphological differentiation from myeloblasts can be difficult. Furthermore, pure erythroid leukemia, a disease associated with complex karyotypes and a dismal clinical outcome, is also a diagnostic challenge because proerythroblasts often lack more mature erythroid differentiation markers. Therefore, having multiple erythroid IHC markers and understanding their specificity and expression patterns throughout erythropoiesis is essential.
This study is the first to systematically evaluate the sensitivity and specificity of GLUT1 IHC for erythroid differentiation in bone marrow biopsy specimens.
GLUT1 IHC is extremely sensitive for erythroid precursors, showing strong membrane staining at all stages of maturation, with slightly weaker staining in the most immature proerythroblasts. This pattern was observed in every case with evaluable erythropoiesis. GLUT1 IHC is also extremely sensitive for blasts with erythroid differentiation in acute leukemia. All cases of pure erythroid leukemia and t-AML with erythroid differentiation showed strong to moderate membrane and cytoplasmic GLUT1 staining in malignant proerythroblasts.
GLUT1 IHC is relatively specific for erythroid differentiation. The only non-erythroid lineage showing any staining in benign bone marrow (including megakaryocytes) was a subset displaying weak but variable cytoplasmic staining. In practice, this staining pattern is easily distinguishable from erythroid GLUT1 expression due to significant differences in staining intensity and cell morphology. In neoplastic cases, GLUT1 was negative in all myeloid neoplasms without erythroid differentiation, including a wide range of diagnostic and immunophenotypic blast differentiations.
In this study, the only lymphoblastic leukemias with GLUT1 staining included a subset of B-ALL, showing weak to moderate staining in lymphoblasts, but significantly weaker than staining in proerythroblasts. This is consistent with published data. Evidence of GLUT1 expression in previously described B-ALL cell lines suggests that the expression identified by IHC in this study represents true staining, not a non-specific artifact.
However, this study did not include lymphomas; additional work is needed to characterize GLUT1 staining patterns in lymphomas. Since GLUT1 IHC is positive in various cancers, the current study does not position GLUT1 as a marker that can be used to determine erythroid lineage in tumors of unknown primary.
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It is a sensitive marker for erythroid differentiation in bone marrow, including a sensitive marker for pure erythroid leukemia.
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It is a specific marker for erythroid differentiation in benign bone marrow, MDS, and within the spectrum of AML. When using GLUT1 positivity as evidence of erythroid differentiation in acute leukemia, lymphoblastic leukemia must be excluded because B-ALL lymphoblasts may show weak/moderate GLUT1 expression.
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GLUT1 is positive in various carcinomas, and its expression pattern in lymphomas is not yet clear. Correlation with morphology and other immunophenotypic findings is necessary when interpreting GLUT1 in neoplastic bone marrow.
Overall, the data from this study indicate that GLUT1 can be added as a sensitive and specific marker to the existing arsenal of erythroid markers.
Related Antibodies from Maxin
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Antibody Name
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Product Number
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Clone Number
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Cellular Localization
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GLUT-1
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MAB-0813
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SPM498
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Cell Membrane
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References:
[1] Kaumeyer B A , Fidai S S , Beenu T , et al. GLUT1 Immunohistochemistry Is a Highly Sensitive and Relatively Specific Marker for Erythroid Lineage in Benign and Malignant Hematopoietic Tissues[J]. American Journal of Clinical Pathology, 2022.
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