Chromosome 9p and 10q losses predict unfavorable outcome in low-grade gliomas

The prognosis of low-grade gliomas (LGGs) varies widely, with overall survival (OS) ranging from a few years to decades. Defining reliable prognostic factors in LGGs has been difficult, but the importance of clinical factors, including gender, age, Karnofsky performance status (KPS), symptoms at diagnosis, tumor size, and extent of tumor resection, has been recently recognized.1–4 To date, the only identified molecular alteration of prognostic importance in LGGs is the 1p–19q co-deletion.5,6 Loss of heterozygosity (LOH) on chromosomes 9p and 10q is rare in LGGs. These alterations are classically associated with high-grade tumors (anaplastic gliomas and glioblastomas)7 and have been found to be of prognostic significance in anaplastic gliomas8 but not in glioblastomas.9 In this study, we analyzed the prognostic impact of LOH on 9p and 10q in a series of LGGs.