Microsatellite instability (deletion frequency and size) was studied in six different loci of the chromosome 17q11-21 region containing the BRCA1 suppressor gene associated with the development of mammary and ovarian carcinomas. DNA samples from tumor and normal tissues of 46 patients with sporadic ovarian neoplasms of different histogenesis and malignancy were studied. Malignant tumors of all histological types studied (serous, endometrioid, mixed epithelial, and carcinosarcoma) exhibited a high loss of heterozygosity without strict correlation with the disease stage. The deletion frequency in a given locus is insignificant in low-grade tumors. Most often deleted regions correspond to the BRCA1 site (marker D17S855, 85.1%) and adjacent proximal (marker D17S800,75.0%) and distal (marker Mfd188,65.5%) regions. No intratumoral molecular-genetic heterogeneity was found in 8 out of 29 (27.5%) patients. For them, the alterations in the BRCA1 region can be considered as an early event associated with malignant transformation. For most ovarian malignant tumors (72.5%) with intratumoral heterogeneity, this is a secondary event and probably is indicative of tumor progression. The high instability of this genome region does not exclude involvement of other genes of the 17q11-21 region in tumor development.
|Original language||English (US)|
|Number of pages||8|
|State||Published - Mar 1 1998|
All Science Journal Classification (ASJC) codes
- Structural Biology