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Comparison of array comparative genomic hybridization (aCGH) to FISH and cytogenetics in prognostic evaluation of chronic lymphocytic leukemia

Authors


Dennis P O’Malley, Clarient, Inc., 31 Columbia, Aliso Viejo, CA 92656-1460, USA. Tel.: (949) 425-5710; Fax: (949) 389-0371; E-mail: domalley@clarientinc.com

Summary

Introduction:  High-resolution array comparative genomic hybridization (aCGH) is a method of evaluating chromosomal alterations over the entire genome. We compared aCGH with routine cytogenetics and FISH in detecting genetic alterations in chronic lymphocytic leukemia (CLL).

Methods:  Array comparative genomic hybridization testing was performed on 55 cases of CLL in addition to a standard panel of FISH probes (ATM on 11q22, trisomy 12, 13q14, p53 on 17p13). The frequency of detecting abnormalities was compared, and discordant results between methodologies were compared.

Results:  Fifty-five CLL cases [male to female ratio of 2.2:1 and a mean age of 71 (52–90)] were analyzed by both aCGH and FISH. This group of CLL cases showed genetic abnormalities by FISH (60%; 27/45). In contrast to FISH, aCGH detected genetic abnormalities in 82% (45/55) of CLL cases; aCGH identified genetic abnormalities not detected by FISH studies in 16% (7/45) of cases, whereas FISH identified abnormalities not detected by aCGH in only 7% (3/45) of cases. Rare recurring genetic alterations were detected by aCGH including losses in 6q, 8p, 10q, 14q32, and 18q and gains in 10q.

Discussion:  Our findings suggest aCGH is an effective technique for evaluating recurring genetic abnormalities in CLL and improves on standard FISH in detecting genetic abnormalities in CLL.

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