Genetic differences between Asian and Caucasian chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a common hematological malignancy in Western countries. However, this disease is very rare in Asian countries. It is not clear whether the mechanisms of development of CLL in Caucasians and Asians are the same. We compared genetic abnormalities in Asian and Caucasian CLL using 250k GeneChip arrays. Both Asian and Caucasian CLL had four common genetic abnormalities: deletion of 13q14.3, trisomy 12, abnormalities of ATM (11q) and abnormalities of 17p. Interestingly, trisomy 12 and deletion of 13q14.3 were mutually exclusive in both groups. We also found that deletions of miR 34b/34c (11q), caspase 1/4/5 (11q), Rb1 (13q) and DLC1 (8p) are common in both ethnic groups. Asian CLL more frequently had gain of 3q and 18q. These suggest that classic genomic changes in the Asian and Caucasina CLL are same. Further, we found amplification of IRF4 and deletion of the SP140/SP100 genes; these genes have been reported as CLL-associated genes by previous genome-wide-association study. We have found classic genomic abnormalities in Asian CLL as well as novel genomic alteration in CLL.