title: The disappearing Barr body in breast and ovarian cancers.
abstract: Interest has recently reawakened in whether loss of the heterochromatic X chromosome (Barr body) is prevalent in certain breast and ovarian cancers, and new insights into the mechanisms involved have emerged. Mitotic segregation errors commonly explain the loss of the inactive X chromosome (Xi), but compromise of Xi heterochromatin in some cancers may signal broader deficits of nuclear heterochromatin. The debated link between BRCA1 and Xi might reflect a general relationship between BRCA1 and heterochromatin, which could connect BRCA1 to both epigenetic and genetic instability. We suggest that heterochromatic instability is a common but largely unexplored mechanism, leading to widespread genomic misregulation and the evolution of some cancers.
authors.affiliation: Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
authors.forename: Gayle J
authors.initials: GJ
authors.lastname: Pageau
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Hall
authors.forename: Shridar
authors.initials: S
authors.lastname: Ganesan
authors.forename: David M
authors.initials: DM
authors.lastname: Livingston
authors.forename: Jeanne B
authors.initials: JB
authors.lastname: Lawrence
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D041321:Chromosomes, Human, X; D005260:Female; D019398:Genes, BRCA1; D006570:Heterochromatin / Q000378:metabolism; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology*; D012728:Sex Chromatin / Q000378:metabolism / Q000473:pathology*
chemical_list: D006570:Heterochromatin