X chromosomal abnormalities in basal-like human breast cancer

Cancer Cell. 2006 Feb;9(2):121-32. doi: 10.1016/j.ccr.2006.01.013.


Sporadic basal-like cancers (BLC) are a distinct class of human breast cancers that are phenotypically similar to BRCA1-associated cancers. Like BRCA1-deficient tumors, most BLC lack markers of a normal inactive X chromosome (Xi). Duplication of the active X chromosome and loss of Xi characterized almost half of BLC cases tested. Others contained biparental but nonheterochromatinized X chromosomes or gains of X chromosomal DNA. These abnormalities did not lead to a global increase in X chromosome transcription but were associated with overexpression of a small subset of X chromosomal genes. Other, equally aneuploid, but non-BLC rarely displayed these X chromosome abnormalities. These results suggest that X chromosome abnormalities contribute to the pathogenesis of BLC, both inherited and sporadic.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism
  • Biological Transport
  • Biomarkers
  • Breast Neoplasms / genetics*
  • Cell Nucleus / metabolism
  • Chromosome Aberrations*
  • Chromosomes, Human, Pair 14 / genetics
  • Chromosomes, Human, Pair 17 / genetics
  • Chromosomes, Human, X / genetics*
  • Cohort Studies
  • CpG Islands / genetics
  • DNA Methylation
  • Female
  • Gene Expression
  • Gene Silencing
  • Genes, X-Linked
  • Humans
  • Neoplasms, Basal Cell / genetics*
  • RNA, Long Noncoding
  • RNA, Messenger / genetics
  • RNA, Untranslated / genetics
  • Uniparental Disomy


  • BRCA1 Protein
  • Biomarkers
  • RNA, Long Noncoding
  • RNA, Messenger
  • RNA, Untranslated
  • XIST non-coding RNA

Associated data

  • GEO/GSE3743
  • GEO/GSE3744