MALIGNANT ASTROCYTOMA-DERIVED REGION OF COMMON AMPLIFICATION IN CHROMOSOMAL BAND 17P12 IS FREQUENTLY AMPLIFIED IN HIGH-GRADE OSTEOSARCOMAS

Recently, we reported a new amplification event that involves marker D 17S67 in 17p12 in three malignant astrocytomas of patients with a very short survival. The amplified region may contain an oncogene implicat ed in astrocytoma tumorigenesis. To determine the extent of the amplif ied regions, we constructed a yeast artificial chromosome contig spann ing the D17S67 region and tested the amplification status of markers t hat map to the contig. We determined a commonly amplified region betwe en markers D17S1311 and D17S1875 with a maximal length of 1,630 kb. By using marker 745R, from within the commonly amplified region, we scre ened 60 high-grade astrocytomas but could not detect additional tumors with the amplification event. This suggests chat the incidence of the amplification event in high-grade astrocytoma is low (5%). It has rec ently been shown by comparative genomic hybridization that amplificati on of 17p11-p12 is a frequent event in high-grade osteosarcomas, occur ring in 20-30% of cases. Since the commonly amplified region is within 17p12, we tested 745R in 20 osteosarcomas, including 6 lung metastase s, and detected amplification in 9 cases (45%). Marker 745R was found to be amplified in 4 of the 6 lung metastases (66%). From this frequen t involvement and the association with clinically aggressive astrocyto mas we conclude that for both tumor types presence of the amplificatio n event seems to correlate with aggressive clinical behaviour. (C) 199 7 Wiley-Liss, Inc.