The locus of the polymorphic epithelial mucin (PEM) tumour antigen on chromosome 1q21 shows a high frequency of alteration in primary human breast tumours.
Tumour and blood leukocyte DNAs from sporadic breast cancer patients were examined for chromosome 1 loss of heterozygosity using a probe for a polymorphic epithelial mucin, PEM, which is expressed in greater than 92% of breast carcinomas as well as in normal lactating breast tissue. Expression is detected by the monoclonal antibodies (MAbs) HMFG-1, -2 and SM-3 which react with epitopes in the 20 amino-acid repeat unit of the core protein. The PEM probe has been mapped to the chromosome band 1q21, a region that is often incriminated in chromosomal rearrangements in breast tumours. Loss of heterozygosity or alteration at the PEM locus was detected in 34% of the 70 informative patients examined. Twenty of the 24 individuals showed loss of an allele, whereas 4 showed gain of an additional allele or amplification of an existing allele. Twenty-eight percent of informative cases exhibited alterations at the MS32 locus, 1q42-43, and 20% had alterations at the short arm locus MS1 at 1p33-35. These findings identify the long arm of chromosome 1 and in particular the region around the PEM gene for localization of a gene whose loss or alteration may, in some tumours, contribute to the progression of disease in breast cancer patients.
Gendler
S J
SJ
Imperial Cancer Research Fund, London, UK.
Cohen
E P
EP
Craston
A
A
Duhig
T
T
Johnstone
G
G
Barnes
D
D
D000951:Antigens, Neoplasm / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000276:immunology; D002869:Chromosome Aberrations; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D002895:Chromosomes, Human, Pair 5; D002897:Chromosomes, Human, Pair 7; D005260:Female; D015321:Gene Rearrangement / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D009077:Mucins / Q000235:genetics / Q000276:immunology*
D000951:Antigens, Neoplasm; D009077:Mucins