A highly polymorphic CA repeat marker at the EBAG9/RCAS1 locus on 8q23 that detected frequent multiplication in breast cancer.
BACKGROUND
Cloning of CpG binding sites in the human genome initially identified EBAG9 (estrogen receptor-binding fragment-associated gene 9), an estrogen-responsive gene mapped to chromosome 8q23. Its product was later found to be identical to RCAS1 (receptor-binding cancer antigen expressed on SiSo cells 1). RCAS1 was recently described as a cancer-surface antigen, implicated in immune escape in a human uterine adenocarcinoma cell line, which turned out to be identical to the EBAG9 molecule.


OBJECTIVE
The study seeks to isolate a highly polymorphic dinucleotide repeat at this locus that detects frequent multiplication of the EBAG9/RCAS1 gene.


METHODS
A fragment containing CA repeat was identified by Southern blotting of bacterial artificial chromosome (BAC) clone containing the EBAG9/RCAS1 gene digested by Hae III, Sau 3A or Rsa I with (GT)20 probe, subcloned and sequenced.


RESULTS
We isolated a polymorphic dinucleotide (CA) repeat sequence from a genomic clone containing the EBAG9/RCAS1 gene located at 8q23. High heterozygosity (0.859) makes this polymorphism a useful marker in genetic studies. This marker detected frequent multiplication of the EBAG9/RCAS1 gene in primary breast cancers (27 of 129 tumours).


CONCLUSIONS
This marker is useful for detecting frequent multiplication of the EBAG9/RCAS1 gene in primary breast cancers and other cancers.
Tsuneizumi
Michiko
M
Department of Molecular Biology, Institute of Gerontology, Nippon Medical School, 1-396, Kosugi-cho, Nakahara-ku, Kawasaki, 211-8533, Japan.
Nagai
Hisaki
H
Harada
Haruhito
H
Kazui
Teruhisa
T
Emi
Mitsuu
M
D000483:Alleles; D000951:Antigens, Neoplasm; D000954:Antigens, Surface / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D018900:Dinucleotide Repeats / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D020161:Physical Chromosome Mapping; D018807:Polymorphism, Single-Stranded Conformational
D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C120762:EBAG9 protein, human