[Cloning of amplified nucleotide sequences of DNA in a patient from a high-risk stomach cancer family].

An abnormally long shorter shoulder of chromosome 21 was identified in 3 out of 4 members of a family at high risk for gastric cancer. We attempted to clone the amplified fragments of DNA of one of the family members who had the same chromosomal marker. This was done after the amplified sequences were enriched by re-association in phenolic emulsion, and 52 clones were obtained. All inserts were separated and each was hybridized on filters containing Hind III DNA of patient O.L. and that of a healthy donor. Hybridization with the genome DNAs of patient O.L. and the donor failed to go through in 9 inserts. Hybridization with all genomic DNAs went through in 34 inserts. Hybrids with one or several Hind III fragments of DNAs of O.L. and the donor were formed in 9 inserts. The size of fragments with varying molecular weight in inserts 6, 9, 11, 30, 39, 43 and 44 identified in the DNA of patient O.L. was 3-10 times that in the DNA of the donor. The differences in the molecular weight and size of the detected bends seem to indicate that we succeeded in cloning at least several different amplified fragments of the genome of the patient.