Hereditary breast cancer: an update on genotype and phenotype.

Hereditary breast cancer: an update on genotype and phenotype.
by Marc Lacroix & Guy Leclercq
Laboratoire Jean-Claude Heuson de Cancérologie Mammaire, Institut
Jules Bordet, Bruxelles, Belgium and InTextoResearch, Baelen, Wallonia,
Belgium.
in New Breast Cancer Research, Nova Sciences Publishers, ISBN
1-59454-932-X (2006) pp27-51.

http://www.geocities.com/m.lacroix/livre4.htm

A minority (5-10%) of breast carcinomas is considered of hereditary
origin. Part of them is associated to mutations in two susceptibility
genes, BRCA1 and BRCA2, which have been extensively studied. For their
part, tumours in the non-BRCA1/BRCA2 breast cancer (BRCAx) families are
increasingly believed to originate from multiple genetic events, as no
"BRCA3" gene has been identified. The existence of specific "portraits"
among hereditary breast carcinomas (HBC) has been questioned. Phenotype
studies have shown that most BRCA1 tumours are part of a "basal
epithelial-like" group of lesions. In contrast, BRCA2 and BRCax HBC are
more heterogenous, as also observed with sporadic carcinomas. Genetic
analysis has also been applied to HBC, notably with the objective of
resolving the heterogeneity of BRCAx lesions. This chapter aims to
summarise recent data on BRCA1, BRCA2, and BRCAx HBC, and to provide
hypotheses on the origin of BRCA1 lesions, their high-frequency of P53
mutations, and their paradoxical relations to oestrogen-sensitivity.

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