DNA index of glial tumors in children: Correlation with tumor grade and prognosis

BACKGROUND. Although DNA index (DI) has prognostic significance in a variety of pediatric malignancies, there are few data regarding its utility in central nervous system (CNS) tumors. We have previously shown that patients with hyperdiploid medulloblastoma have a significantly better survival than those whose tumors are diploid. Here, we examine the effect of DI and tumor grade on the progression free survival (PFS) of 57 patients with variety of glial neoplasms. METHODS. DI was determined by flow cytometry on freshly obtained tumor tissue from the initial diagnostic specimens; a DI = 1.0 was defined as diploid (DIP). 1.0 < DI < LI as near diploid (NDIP), and DI > LI as hyperdiploid (HYP). Tumors were historically graded according to the World Health Organization classification. RESULTS. There were 21 Grade I tumors, 20 Grade II, 8 Grade III, and 8 Grade IV. Among 41 low grade tumors (Grade I-III), 39 were DIP or NDIP, and 2 were HYP. Among the 16 high grade tumors (Grade III-IV), 9 were DIP, 2 NDIP, and 5 HYP. The 4-year PFS of low grade tumors was 70% (standard deviation [SD] 12%) versus 8% (SD 7%) for high grade tumors. There was a significant correlation between low grade tumor histology and a DIP/NDIP DI (P = 0.015), and univariate analysis suggested improved PFS was associated with DIP/NDIP tumors (P = 0.05). However, DI did not remain a significant prognostic factor after being stratified by tumor grade (P = 0.87). CONCLUSIONS. Unlike medulloblastoma, DI is not an independent prognostic factor in pediatric glial tumors.