Frequent Loss of the Cyclin‐dependent Kinase‐4 Inhibitor Gene in Human Gliomas

Abstract
Studies have shown that homozygous deletion of the cyclin‐dependent kinase‐4 inhibitor (CDK41) gene, which is mapped to chromosome 9p21, is frequently observed in various types of human cancers. Here we report that the CDK4I gene was deleted in gliomas. Eight cell lines derived from glioblastomas and samples from 14 patients with various grades of gliomas were examined by Southern blot analysis. We found that the CDK4I gene was deleted in 7 of 8 (87.5%) cell lines and 7 of 9 (78%) samples from high‐grade glioma patients, whereas it was deleted in 1 of 5 (20%) low‐grade glioma samples. These results suggested that inactivation of the CDK4I gene may play an important role in the progression of human glioma.