Abstract 1132: PTPRD is a frequent tumor suppressor in malignant astrocytoma

• Published in: Cancer research (Chicago, Ill.) Ill.), 2010-04, Vol.70 (8_Supplement), p.1132-1132
• Main Authors: Misra, Anjan, Smirnov, Ivan, Morrow, Colin, Eschbacher, Jenny, Schendel, Cheryl, Kharbanda, Samir, Phillips, Heidi, Coons, Stephen, Feuerstein, Burt G.
• Format: Article
• Language: English
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM10-1132

A slew of loss of heterozygosity studies for over more than a decade indicated existance of tumor suppressor/s other than p16 on 9p. With high resolution DNA microarray data, infrequent loss of a locus at 9p24 have been reported in neuroblastoma, esophageal, colon and lung cancers. Along with >30% loss of whole arm of 9p, we have observed occasional homo and heterozygous loss of a ∼2.6Mb locus, about 10Mb away from p16 gene on 9p in a few glioblastoma multiforme (GBM). Out of 14 genes located in this minimum deletion region, PTPRD expression was lost in ∼65-88% GBM (n=181) and more than 40% AA (n=48). The TCGA data showed similar frequency of loss of PTPRD expression, and mutation in ∼6% of GBM. Compared to nonneoplastic brain, the anaplastic astrocytoma (AA) and GBM had significant loss (p=0.0003 and 3.7 × 10-7, respectively) of PTPRD in our sample set; and TCGA GBM (p=2.7 × 10-14). Earlier we reported 3 genetic GBM subgroups: proneural, proliferative and mesenchymal where proneural GBM have relatively better survival than the others (Phillips et al, 2006). PTPRD expression loss were more significant in proliferative and mesenchymal GBM (P=3.7 × 10-8 and 2.6 × 10-7, respectively) than in proneural (p=0.0001) GBM, suggesting its expression level could be associated with survival. In a set of 306 TCGA GBM with survival data, PTPRD loss was associated with survival (log rank p