Apparent Mendelian inheritance of breast and colorectal cancer: chance, genetic heterogeneity or a new gene?
It is not uncommon for cancer geneticists to be referred families with apparently Mendelian co-inheritance of breast and bowel cancer. Such families present a particular problem as regards the intensity of their screening for these diseases and the utility of genetic testing. Many 'breast-colon' cancer families probably result from chance clustering of two common cancers. Other 'breast-colon' cancer families may result from known cancer syndromes, such as hereditary breast-ovarian cancer or hereditary non-polyposis colon cancer, either by conferring a high risk of one cancer type and a slightly increased risk of the other, or through a predisposition to one of the two cancers and chance occurrence of the other. Anecdotally, however, many geneticists wonder about the existence of a distinct 'breast-colon cancer syndrome', since some families present good a priori evidence of genetic disease and yet cannot readily be accounted for by known genes or chance. The identification of unknown 'breast-colon cancer' genes is likely to be difficult, relying primarily on candidate gene analysis, including loci separately implicated in breast or colorectal cancer, or in other multiple cancer syndromes. Studies such as those on APC I1307K and CHEK2 1100delC may suggest the way forward for the identification of 'breast-colon cancer' genes.
Cancer Research UK, Colorectal Unit, St. Mark's Hospital, Harrow, UK.
L
L
Lipton
H J
HJ
Thomas
R A
RA
Eeles
R S
RS
Houlston
M
M
Longmuir
R
R
Davison
S V
SV
Hodgson
V A
VA
Murday
C G
CG
Norbury
C
C
Taylor
I P
IP
Tomlinson
D000328:Adult; D001943:Breast Neoplasms / Q000235:genetics*; D064447:Checkpoint Kinase 2; D015179:Colorectal Neoplasms / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D017491:Genes, APC; D018740:Genetic Heterogeneity; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics
D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases