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Researchers Identify Implications Of Chromosome 11 Deletion In MDS

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Published: Sep 10, 2010 8:01 am
Researchers Identify Implications Of Chromosome 11 Deletion In MDS

American researchers have identified the clinical implications of a deletion in chromosome 11 in myelodysplastic syndromes. They found that this type of chromosomal abnormality is associated with primary myelodysplastic syndromes and distinct disease characteristics. They also found that the abnormality is not associated with rearrangements of a gene linked to leukemia.

Cells contain DNA that is condensed into chromosomes. Most human cells contain 23 pairs of chromosomes. Chromosomal abnormalities are the result of unbalanced changes to the structure of a chromosome, which may occur through deletions, insertions, duplications, or movement of chromosomal regions.

Myelodysplastic syndromes (MDS) patients with a deletion in chromosome 11 (del(11q)) are currently considered intermediate-risk according to the International Prognostic Scoring System.

Deletions and abnormal rearrangements of chromosome 11 are common in acute myeloid leukemia. Because del(11q) is a rarer deletion in MDS, its clinical significance had not previously been determined.

In their study, researchers from three medical centers across the United States analyzed data of MDS patients at their institutions to determine the clinical significance of del(11q) in MDS.

They identified 32 MDS patients with del(11q) as either their sole chromosomal abnormality or as one of two chromosomal abnormalities which corresponded to a rate of 0.6 percent of this chromosomal abnormality in their MDS patients.

Of those 32 patients with del(11q), 15 (47 percent) were male and 17 (53 percent) were female, which according to the researchers was “unlike the male predominance seen in most patients with MDS.”

Most of the patients (88 percent) were diagnosed with primary MDS, and 20 patients (65 percent) were dependent on red blood cell transfusions.

Data of these 32 patients were compared to data of 196 other intermediate-risk MDS patients without a chromosome 11 deletion.

The researchers found that patients with del(11q) experienced low platelet counts less often and less intensely than MDS patients without this genetic abnormality.

There was no significant difference in overall median survival between MDS patients with del(11q) and other intermediate-risk MDS patients.

The overall median survival of the del(11q) patients was 35 months. It was 14 months for MDS patients with one or two genetic abnormalities and 48 months for intermediate-risk patients without genetic abnormalities.

The del(11q) MDS patients studied had significantly higher overall median survival compared to MDS patients who had three or more genetic abnormalities (10 months).

When chromosome 11 abnormalities were compared between the MDS patients with del(11q) and 17 patients with acute myeloid leukemia, the MDS patients examined showed no abnormal rearrangement of the myeloid/lymphoid leukemia gene. All 17 patients with acute myeloid leukemia had abnormal rearrangements of the gene.

The myeloid/lymphoid leukemia gene is associated with human leukemia and is located on chromosome 11.

For more information, please see the study in Leukemia Research (abstract).

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