title: Detection of loss of heterozygosity at RAD51, RAD52, RAD54 and BRCA1 and BRCA2 loci in breast cancer: pathological correlations.
abstract: Loss of heterozygosity (LOH) in loci of the 15q15.1, 12p13, 1p32, 17q21 and 13q12-13 regions may collaborate in the inactivation of RAD51, RAD52, RAD54, BRCA1, BRCA2 and possibly other genes implicated in the repair of double-stranded DNA and in DNA recombination. We investigate allelic losses in microsatellites of the RAD51, RAD52, RAD54, BRCA1 and BRCA2 regions, and their correlations with nine pathologic parameters in 127 breast carcinomas. The LOH analysis was performed by amplifying DNA by PCR, using 15 markers of the 15q15.1, 12p13.3, 1p32, 17q21 and 13q12-13 regions. LOH was found in the RAD51 region in 32% of tumours, in the RAD52 region in 16%, in RAD54 in 20% and in the BRCA1 and BRCA2 regions in 49% and 44% respectively. Significant correlations between one or more regions with concomitant LOH and pathologic parameters were observed with respect to age (P = 0.008), oestrogen receptor content (P = 0.03), progesterone receptors (P = 0.003), higher grade (P = 0.001), more advanced stage (P = 0.004) and peritumoural vessel involvement (P < 0.0001). The number of cases in which LOH was observed simultaneously in two or more regions was always higher than expected on the basis of their statistical probability, and curiously, the three patients with LOH at five regions concomitantly were under the age of 30 years. These results suggest that LOH at these regions could be related to breast cancer, and probably to a poor tumour prognosis.
authors.affiliation: Department of Medical Oncology, Clinica Puerta de Hierro, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Gonzalez
authors.forename: J M
authors.initials: JM
authors.lastname: Silva
authors.forename: G
authors.initials: G
authors.lastname: Dominguez
authors.forename: J M
authors.initials: JM
authors.lastname: Garcia
authors.forename: G
authors.initials: G
authors.lastname: Martinez
authors.forename: J
authors.initials: J
authors.lastname: Vargas
authors.forename: M
authors.initials: M
authors.lastname: Provencio
authors.forename: P
authors.initials: P
authors.lastname: España
authors.forename: F
authors.initials: F
authors.lastname: Bonilla
mesh_terms: D000367:Age Factors; D000368:Aged; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein; D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D002877:Chromosomes, Human / Q000235:genetics; D004265:DNA Helicases; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005656:Fungal Proteins / Q000235:genetics*; D006801:Humans; D019656:Loss of Heterozygosity; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics*; D009367:Neoplasm Staging; D010641:Phenotype; D016133:Polymerase Chain Reaction; D051135:Rad51 Recombinase; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D019313:BRCA1 Protein; D024682:BRCA2 Protein; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009363:Neoplasm Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D045643:DNA Repair Enzymes