From the Guidelines
Yes, t(13;3) and monosomy 7 can develop in Myelodysplastic Syndrome (MDS) with excess blasts. Chromosomal abnormalities are common in MDS, with approximately 50% of patients showing cytogenetic aberrations at diagnosis, as noted in the european recommendations and quality assurance for cytogenomic analysis of haematological neoplasms 1. Monosomy 7 (complete loss of chromosome 7) is particularly common in MDS, occurring in about 10% of cases, and is associated with a poor prognosis. The translocation t(13;3), while less common than monosomy 7, can also occur in MDS with excess blasts. These cytogenetic abnormalities are significant because they influence disease progression, treatment response, and overall survival. MDS with excess blasts (formerly known as RAEB in older classification systems) represents a more advanced form of MDS with increased bone marrow blast percentage (5-19%), and patients with this subtype are more likely to develop complex karyotypes including these specific abnormalities. Some key cytogenetic abnormalities in MDS include:
- Unbalanced abnormalities: −7 or del(7q), −5 or del(5q), i(17q) or t(17p), −13 or del(13q), del(11q), del(12p) or t(12p), del(9q), idic(X)(q13) as mentioned in the myelodysplastic syndromes: esmo clinical practice guidelines for diagnosis, treatment and follow-up 1. The presence of monosomy 7 particularly indicates a higher risk of transformation to acute myeloid leukemia (AML) and may influence treatment decisions, potentially leading clinicians to consider more aggressive therapeutic approaches including consideration for allogeneic stem cell transplantation in eligible patients. Given the potential for these cytogenetic abnormalities to impact prognosis and treatment, it is essential to perform cytogenetic analysis in all patients with suspected MDS, as recommended by the european recommendations and quality assurance for cytogenomic analysis of haematological neoplasms 1. In cases where no or insufficient metaphases are obtained, array or FISH analysis for monosomy 5/deletion of 5q and monosomy 7/deletion 7q must be undertaken, and analysis can be extended to include trisomy 8, TP53 deletion, and 20q deletion 1. Overall, the development of t(13;3) and monosomy 7 in MDS with excess blasts highlights the importance of cytogenetic analysis in the diagnosis and management of MDS, and the need for clinicians to consider these abnormalities when making treatment decisions.
From the Research
Cytogenetic Abnormalities in Myelodysplastic Syndromes (MDS)
- Cytogenetic abnormalities are common in MDS, with approximately 50% of patients having chromosomal abnormalities 2
- Numerical aberrations such as monosomy 5 or 7, trisomy 8, and loss of the Y-chromosome are frequently observed in MDS patients 2
- Structural abnormalities, including deletions of the long arm of chromosome 5,7, or 8, are also present in some MDS cases 2
Specific Abnormalities: t(13;3) and Monosomy 7
- There is limited information available on the specific abnormalities t(13;3) and monosomy 7 in the context of MDS with excess blasts
- However, monosomy 7 is a known cytogenetic abnormality in MDS, and its presence is associated with a poor prognosis 3, 2
- The study by 3 reported that 8 out of 20 patients with myeloid neoplasms associated with t(3;12)(q26.2;p13) had chromosome 7 abnormalities, including monosomy 7
MDS with Excess Blasts
- MDS with excess blasts is a high-risk subtype of MDS, characterized by an increased number of blasts in the bone marrow or blood 4, 5, 6
- Patients with MDS with excess blasts have a higher risk of transformation to acute myeloid leukemia (AML) and a poorer prognosis compared to other MDS subtypes 6
- The optimal treatment approach for MDS with excess blasts is still being debated, with options including allogeneic hematopoietic stem cell transplantation (allo-HCT) and bridging therapy with azacitidine or combination chemotherapy 4, 5