ISCN 1991

The immense amounts of new data accumulated on neoplasia-associated chromosome aberrations have revealed certain inadequacies in the system now used universally to describe tumour karyotypes. Consequently, the Standing Committee on Human Cytogenetic Nomenclature decided to establish new guidelines to avoid confusion in the literature and to improve communication among scientists. This report proposes recommendations and simple, uniform guidelines for the description of most acquired clonal karyotypic abnormalities. The guidelines are based on normal chromosomes and constitutional chromosome aberrations (ISCN 1985). However, the definitions of some terms have been slightly modified and some new terms describing aberrations found primarily in neoplastic cells have been added. Approved by the ISCN Standing Committee, the report incorporates and supersedes all previous ISCN recommendations on cancer cytogenetics in man. The Committee recommends that this nomenclature system also be used in the description of acquired chromosome aberrations in neoplasms of other species.