title: BCL2 translocation frequency rises with age in humans.
abstract: The background frequency of t(14;18) (q32;q21) chromosomal translocations at the locus associated with B-cell leukemia/lymphoma-2 (BCL2) was determined from a survey of the peripheral blood lymphocytes (PBLs) of 53 living individuals and from tissues of 31 autopsies by using a nested PCR assay. The translocation was detected in 55% of PBLs and 35% of autopsied spleens with a frequency of between less than 1 to 853 translocations per million cells. Translocations copurified with B lymphocytes. The frequency of translocations significantly increased with age in PBLs and spleens, as does human risk for lymphoma. Average translocation frequency was more than 40 times greater in the spleen and 13 times greater in the peripheral blood in the oldest individuals (61 yr and older) compared with the youngest individuals (20 yr or younger). Particular t(14;18)-bearing clones persisted over a period of 5 months in two individuals. These findings demonstrate that clones harboring the oncogenic t(14;18) chromosomal translocation are commonly present in normal humans, that such clones are long-lived, and that they rise in frequency with age. A multihit model of lymphomagenesis involving t(14;18) translocation followed by antigen stimulation is proposed.
authors.affiliation: Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90033.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: A M
authors.initials: AM
authors.lastname: Hernandez
authors.forename: D
authors.initials: D
authors.lastname: Shibata
authors.forename: G A
authors.initials: GA
authors.lastname: Cortopassi
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001402:B-Lymphocytes; D001483:Base Sequence; D002470:Cell Survival; D002648:Child; D002883:Chromosomes, Human, Pair 14; D002887:Chromosomes, Human, Pair 18; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005333:Fetus; D006801:Humans; D008223:Lymphoma / Q000235:genetics; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009857:Oncogenes; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2; D013154:Spleen / Q000166:cytology; D014178:Translocation, Genetic
chemical_list: D017931:DNA Primers; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2