AMPLIFICATION OF SATELLITE DNA AT 16Q11.2 IN THE GERM-LINE OF A PATIENT WITH BREAST-CANCER

Cytogenetic analyses of peripheral blood cells of breast cancer patien ts unveiled in one case a grossly enlarged G-band in one copy of chrom osome 16 (16qh+), which scored also strongly positive in C-banding. Fl uorescence in situ hybridization with both a total chromosome 16 libra ry and with probe pHuR195 detecting locus D16Z3 further documented the increase of the copy number of the corresponding satellite DNA at 16q -11.2. Slot-blot analyses with pHuR195 revealed an approximately 10-fo ld amplification compared to a random selection of normal chromosomes 16. The chromosome 16 carrying amplified DNA is passed on to one of 3 children, who shows no obvious anomaly. Previous studies (Kokalj-Vokac N, Alemeida A, Gerbault-Seureau M, Malfoy B, Dutrillaux B: Gene Chrom osome Cancer 7: 8-14, 1993) had revealed that satellite DNA in chromos ome 16 often participates in interchromosomal recombinations, preferen tially with chromosome 1, in breast cancer cells. Although the increas ed copy number of satellite DNA could represent a polymorphism, it mig ht provide an enlarged target for recombination events and therefore c ould be a determinant for cancer predisposition.