Mutations In Chromosome 7 Are Associated With Better MDS Prognosis Than Other Chromosomal Abnormalities (ASH 2010)
An international team of researchers has found that myelodysplastic syndromes patients with total or partial deletions in chromosome 7 show better survival and were slower to progress to acute myeloid leukemia than patients with other chromosomal abnormalities.
Based on their findings, the researchers suggested that mutations in chromosome 7 should no longer be considered a poor genetic risk factor, but an intermediate risk factor instead.
They also recommended that their findings be considered when the International Prognostic Scoring System (IPSS) for myelodysplastic syndromes (MDS) is next revised.
Dr. Julie Schanz of the Georg-August-Universität in Göttingen, Germany, presented the findings at the 2010 American Society of Hematology (ASH) conference in Orlando last month.
DNA is stored inside of cells in the form of chromosomes. Chromosomal abnormalities can include deletions, in which pieces of DNA are missing.
Chromosomal abnormalities affect how DNA works. Having certain chromosomal abnormalities can lead to poor MDS prognoses. (For more information on chromosomal abnormalities in MDS, please see the related Beacon news.)
Chromosome 7 mutations (also known as -7, monosomy 7, or deletion 7q) occur in about 11 percent of MDS patients. According to the IPPS, chromosome 7 mutations are classified as poor genetic factors when determining an MDS patient’s risk of progressing to acute myeloid leukemia.
However, some research has recently indicated that chromosome 7 mutations should be classified as intermediate risk factors.
Researchers from Europe, Canada, and the United States worked together to re-analyze the significance of deletion 7q in MDS patients.
The analysis included data from 2,901 MDS patients, 60 of which (2.1 percent) had a genetic mutation in chromosome 7 only.
The researchers did not observe any differences in red blood cell counts and white blood cell counts between patients who had deletion 7q and those who did not.
However, the researchers found that patients with deletion 7q were younger (median age of 66 years) than patients without the mutation (a median age of 70 years) and had significantly lower platelet counts.
When deletion 7q patients were compared to MDS patients who had other poor-risk chromosomal abnormalities, deletion 7q patients had significantly longer survival times and were slower to progress to acute myeloid leukemia.
Deletion 7q patients had a median overall survival of 16.0 months, compared to 5.7 months for MDS patients with other poor-risk chromosomal abnormalities and 47.4 months for MDS patients with no chromosomal abnormalities.
The median amount of time before deletion 7q patients progressed to acute myeloid leukemia was 42.2 months, compared to 8.2 months for MDS patients with other poor-risk chromosomal abnormalities. The median time to progression has not been reached yet for MDS patients with no chromosomal abnormalities.
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