THE FREQUENCY AND MECHANISM OF LOSS OF HETEROZYGOSITY ON CHROMOSOME 11q IN BREAST CANCER

✍ Scribed by TOMLINSON, I. P. M.; NICOLAI, H.; SOLOMON, E.; BODMER, W. F.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 586 KB
• Volume: 180
• Category: Article
• ISSN: 0022-3417
• DOI: 10.1002/(sici)1096-9896(199609)180:1<38::aid-path638>3.0.co;2-c

✦ Synopsis

Loss of heterozygosity (LOH, allele loss) occurs frequently on the long arm of chromosome 11 in breast cancer. Seventy-one paired tumourlnormal DNA samples from breast cancer patients under 50 years old were studied for allele loss at four microsatellite loci on llq: DlIS29 (11q23.3), NCAM(llq22923), DllS968 (llqtel), and DZZS1313 (llqcen). The maximum frequency of LOH (-35 per cent) was found a t the DIlS29 and NCAM loci. This result is consistent with previous studies and the frequency of allele loss is moderate to high compared with the usual baseline of 0-20 per cent. In most of the cases studied, LOH on chromosome l l q could be accounted for by one of two mechanisms. Either chromosomal non-disjunction had occurred, or sequences stretching from the telomere a t least as far as NCAM had undergone deletion or mitotic recombination. These results suggest that a putative tumour suppressor gene is most likely to exist near llq22423. There was a very low frequency of microsatellite instability in the tumours. An association was found between lack of progesterone receptor (PgR) expression and LOH at NCAM, suggesting that deletion of sequences on l l q may prevent high levels of PgR expression in some cases.