The Tumor Biomarker Series: PTEN and LOH of chromosome 10

Loss of heterozygosity (LOH) of chromosome 10 occurs in most GBMs and less frequently in grade II and III diffuse astrocytomas. The phosphatase and tensin (PTEN) gene at 10q23.3 has been most strongly implicated as a glioma-related tumor suppressor on chromosome 10q, with PTEN mutations identified in about 25% of GBMs and less frequently in grade III astrocytomas. Losses of chromosome 10 and mutations in PTEN are considered to be specific for astrocytic differentiation and are rare in oligodendrogliomas. They are also markers of high-grade progression and aggressive clinical behavior in astrocytomas.