The sick lobe concept

Abstract

Breast cancer is the most common malignancy among younger women worldwide [Boyle, Ferlay, Ann Oncol 16(3):481-8, 2005]. Women are at 100 times higher risk of getting breast cancer during their lifetime than men. The lifetime risk of getting the disease is, at least, fivefold higher in carriers of mutated BRCA1 and BRCA2 genes than in the normal population [Easton et al., Am J Hum Genet 61:120-8, 1997; Ford et al., Lancet 343: 692-5, 1994]. Certain geographic areas in the USA, Europe, Australia, and Canada are well known for their exceptionally high breast cancer incidence [Clarke et al., Breast Cancer Res 4:R13, 2002 ]. Female gender, carrying a mutated gene, living in a high-incidence country, and many other known cancer risk factors are characteristics of the entire organism and influence the genetic construction, as well as the milieu, of all the cells in the body. However, breast cancer develops in one quadrant of one breast in the vast majority of cases. This simple observation indicates presence of at-risk tissue in the breast that is more sensitive to oncogenic stimuli than the other structures of the human body. In our view, this at-risk tissue corresponds to a sick breast lobe [Tot, Virchows Arch 447:1-8, 2005].