Molecular loss of heterozygosity studies on human gliomas have shown several regions on chromosome 10 frequently deleted in higher grade tumors, suggesting that chromosome 10 may contain several tumor suppressor genes. We assessed loss of heterozygosity with microsatellite markers in 20 gliomas, consisting of various grades and containing two chromosome 10 copies. The locus that exhibited the most loss (69%) was the region bordered by D10S249 and D10S558 and inclusive of D10S594, with a linkage distance of 3 cM. This region was noted to be deleted in various grades of tumor, including low- and high-grade tumors. These results suggest that chromosome region 10p15 is involved in human gliomas of diverse grades and that this region may harbor genes important in the development of and progression to the malignant phenotype.