PREDISPOSITION FOR BREAST-CANCER IN CARRIERS OF CONSTITUTIONAL TRANSLOCATION 11Q22Q

A translocation between the long arms of chromosomes 11 and 22, t(11;2 2)(q23;q11), is the most frequent constitutional reciprocal translocat ion in man. This chromosome abnormality has not previously been report ed to be associated with an increased risk for neoplasia. The observat ion of one patient with a constitutional translocation t(11q;22q) and breast cancer prompted us to study the relationship between these two conditions. The incidence of breast cancer was determined in carriers of t(11q;22q). The karyotypes were determined by QFQ-banding, and the breakpoints were then further characterized by fluorescent in situ hyb ridization. Eight families with a total of 22 balanced carriers were f ound. In five of these families there was one case of breast cancer ea ch. In another family a case of an unknown malignancy was reported in one member. No other malignancies were found among these patients. The number of breast cancer cases was significantly higher than expected among the translocation carriers (P <.001). The chromosomal breakpoint s showed the same localization with the markers used, in the seven fam ilies studied. The association of constitutional translocation t(11q;2 2q) and breast cancer identifies a subset of patients with a highly in creased risk for breast cancer who would benefit from counseling and s creening. It also suggests the involvement of genes on 11q and/or 22q, in the tumorigenesis of breast cancer.