Chromosomal Instability: A Probable Unfavorable Prognostic Factor For Patients Of Myeloidysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous hematopoetic stem cell clonal disorders with a high frequency of karyotypic abnormalities (40-60%). Among karyotypic abnormalities, abnormal chromosome numbers (aneuploidy) occurs frequently. In aneuploidy, chromosomal instability (CIN) is defined as persistent mis-segregation of whole chromosomes and is caused by defects during mitosis with an odd number of chromosomes. CIN is associated with tumor heterogenesis, multidrug resistance and aggressiveness in solid tumor. Hence, we performed a one-center study on MDS patients to uncover the role of CIN in MDS clinical development.

A total of 104 cases , 62 male and 42 female, aged from 15 years to 89 years, were tested by fluorescent in situ hybridization (FISH) and karyotypic analysis before any therapeutic intervention. According to the cytogenetic analysis of those two technology they were separated into 5 groups including: CIN, normal karyotype, complex karyotype excluding CIN, deletion chromosome 7 abnormality and other chromosomal abnormalities. All cases were followed up for a median of 19.5 months.

Karyotyping and FISH identified 70 (67.3%) patients with abnormal karyotypes containing 32 cases of CIN, 9 cases of deletion chromosome 7 abnormality and 5 cases of complex karyotype excluding CIN. The median survival for CIN group was 13 months (incredible interval:6-20 months) compared with 23 months (incredible interval :20-27 months) in all cases, 44months in normal karyotype, 23 months in deletion chromosome 7 abnormality and 13 months in complex karyotype excluding CIN group (P=0.001 for log rank method). In CIN group, 11 cases transformed into acute leukemia with a incidence of 34% with no significant difference with total cases. And the length of time for leukemia transformation shows no significant difference between CIN group and total cases.

Chromosomal instability in MDS patients of the study revealed worst prognosis compared with other groups. This may suggest that chromosomal instability in MDS chromosomal abnormality confer a significant independent adverse impact on patients survival. However this effect might have no relation to leukemia transformation.

No relevant conflicts of interest to declare.