Comparison of Array Comparative Genomic Hybridization (CGH) to FISH and Cytogenetics in Prognostic Evaluation of CLL
C Giudice, AS Chang, D Chang, TS Barry, MK Hibbard, S Chen, R Chen, DP O'Malley. Clarient Inc., Aliso Viejo, CA
Background: Chronic lymphocytic leukemia (CLL) is a common hematologic neoplasm. Evaluation of prognosis in CLL is based on genetic findings and the most commonly used studies are cytogenetics and targeted fluorescence in situ hybridization (FISH). High resolution array comparative genomic hybridization (aCGH) is a relatively new and robust method of evaluating chromosomal alterations. We compared aCGH with cytogenetics and FISH in detecting genetic alterations in newly-diagnosed CLL cases.
Design: aCGH testing was performed on 55 cases of CLL in addition to a panel of FISH probes (ATM on 11q22, trisomy 12, 13q14, p53 on 17p13 using a standard cutoff for positivity of 10%). These were compared to a control group of 100 CLL with cytogenetic and FISH results. The frequency of abnormalities was compared between the groups and discordant results between methodologies were compared.
Results: In the control group (n=100), the mean age was 71 (52-86) with a male to female ratio of 1.6:1. Genetic abnormalities were detected by cytogenetics in 19% (19/100) of cases as compared to FISH which detected abnormalities in 66% (66/100) of cases (Table 1). An additional group of 55 CLL cases [male to female ratio of 2.2:1 and a mean age of 71 (52-90)] was analyzed by both aCGH and FISH. This additional group of CLL cases showed a similar frequency of genetic abnormalities by FISH (60%; 27/45). In contrast to FISH, aCGH detected genetic abnormalities in 82% (45/55) of CLL cases.
|SUBSET I (n=55)||82% (45/55)||60% (27/45)||21% (3/14)|
|SUBSET II (n=100)||N/A||66% (66/100)||19% (19/100)|
|TOTAL (n=155)||82% (45/55)||64% (93/145)||19% (22/114)|