Comparative genomic hybridization study on pooled DNAs from tumors of one clinical-pathological entity

Comparative genomic hybridization (CGH) was performed using DNAs pooled from numerous specimens from tumor categories studied case-by-case. The series of six DNA pools consisted of 28 diffuse centroblastic lymphomas (DCL), 28 gastrointestinal stromal tumors (GIST), 21 primary chondrosarcomas (CS), 17 samples from the Ewing family of tumors (ET), 14 liposarcomas (LS), and 14 mesotheliomas (MS). Losses and gains present in at least 50% of the individual specimens were always detected in the pooled DNAs. The loss of the whole p-arm of chromosome 1 was observed even when the affected proportion of individual specimens was only 25%. Gains were also detected at frequencies lower than 50%, but with a high-level amplification in one or more specimens. In conclusion, the present pooled DNA study revealed the following changes: DCL had a gain at 18q22-qter; GIST had losses at 14 and 22q12, and gains at 5p, 8q22-24, 17q22-qter, and 19q13; ET had gains at 1q and 8q13-qter; LS had gains at 1q21-25 and 12q; and MS had a loss at 9p22-pter. No changes were observed in the CS DNA pool. The results from individual specimens also stressed the importance of these chromosomal regions to the tumorigenesis in the corresponding malignancies. This pooled DNA approach can thus be used for fast screening of recurrent DNA copy number in a specific tumor entity.