Allelic Loss at the BRCA1 and BRCA2 Loci in Sporadic Breast Carcinoma Using Paraffin Embedded Tissue

ABSTRACT

BACKGROUND: Germline mutations in the breast cancer-associated genes BRCA1 and BRCA2 confer susceptibility and a lifetime risk of breast. Several morphological and clinical features have been attributed to hereditary tumors. However, in sporadic breast cancer, the interrelationship between the loss of heterozygosity (LOH) of these loci and clinical features remains to be fully elucidated. METHODS: Microdissected paraffin-embedded tissue blocks of 48 cases of surgically resected breast carcinoma were investigated to identify the LOH of BRCA1 and BRCA2 using microsatellite markers. RESULTS: Of 48 cases, 22 (45.9%) exhibited LOH at BRCA1 locus while in 29 out of 48 (60.4%) cases LOH was observed for the BRCA2 region. There was no significant correlation between LOH at BRCA1/2 and the patient's age, tumor size, histologic grade or lymph node metastasis. When comparing the frequency of LOH with the expression of several prognostic factors, such as p53, c-erb B2 protein, estrogen and progesterone receptor using immunohistochemical stain, there was only correlation with LOH at BRCA2 and the progesterone receptor. CONCLUSIONS: Our results suggest that allelic deletion play a role to the development of sporadic breast cancers.