Genetic analysis of sorted Hodgkin and Reed-Sternberg cells using comparative genomic hybridization

Hodgkin and Reed-Sternberg (H and RS) cells are generally considered to be the neoplastic cells of Hodgkin's disease (HD); however, such cells are fou nd only in a minority of HD lesions. Very few data have so far been publish ed on the cyogenetic abnormalities in HD. An analysis of unknown genetic ab errations has only recently become possible through the use of comparative genomic hybridization (CCH), which is based on the competitive binding of t umor and control DNA to metaphase chromosomes. In order to exclude the reac tion of non-tumor cells, we used 100 sorted H-RS cells as the tumor DNA, th en 100 sorted reactive T cells or B cells as the control DNA. We obtained t he amplified DNA, using degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR). In addition, to confirm whether or not the lymphocytes in the background were reactive, we performed CGH with 100 sorted B cells a nd 100 sorted T cells. CGH was thus performed on 9 HDs, including 6 cases o f mixed-cellularity (MC) sub-type and 3 cases of nodular-sclerosis (NS) sub -type. CGH of the B and T cells showed no genetic changes in any cases. In contrast, CGH of H-RS cells revealed both gains and losses of DNA in all 9 cases, and multiple changes were also observed. In situ hybridization showe d an Epstein-Barr-virus infection in 5 cases of MC; however, no definite re lationship was observed between the EBV infection and genetic changes. The most commonly observed genetic aberrations were a loss on 16q11/21 in 6 cas es, a gain on 1p13 in 5 cases, and a gain on 7q35/36 in 5 cases. The large number of chromosomal alterations in HD suggests, therefore, that an increa sed degree of genetic instability play a role in the formation of H-RS cell s. (C) 1999 Wiley-Liss, Inc.