PTEN and DMBT1 homozygous deletion and expression in medulloblastomas and supratentorial primitive neuroectodermal tumors.
Medulloblastoma, which accounts for 20-25% of all childhood brain tumors, is defined as a primitive neuroectodermal tumor (PNET) located in the cerebellum. Supratentorial PNET are less frequent than medulloblastoma. But their clinical outcome is worse than in medulloblastomas. Chromosome 10q contains at least 2 tumor suppressor genes that might play a role in brain tumor development: PTEN and DMBT1. The aim of this study was to compare the status of homozygous deletion and expression of PTEN and DMBT1 genes in PNET primary tumor samples and cell lines. Homozygous deletions of PTEN and DMBT1 were studied in 32 paraffin-embedded PNET samples (23 medulloblastomas and 9 supratentorial PNET) and in 7 PNET cell lines, by differential PCR and by FISH. PTEN homozygous losses were demonstrated in 7 medulloblastomas (32%) and in no supratentorial PNET, while homozygous deletions of DMBT1 appeared in 1 supratentorial PNET (20%) and in 7 medulloblastomas (33%). No homozygous deletion of PTEN or DMBT1 was detected in any of the PNET cell lines either by differential PCR or by FISH. Expression study of the 2 genes was performed in the 7 PNET cell lines by RT-PCR. One PNET cell line lacked PTEN and DMBT1 expression, while 2 medulloblastoma cell lines did not express DMBT1. Our results add some positive data to the hypothesis that supratentorial PNETs and medulloblastomas might be genetically different.
Inda
María Mar
MM
Laboratorio de Neuro-Oncología Molecular, Universidad de Navarra, 31008 Pamplona, Spain.
Mercapide
Javier
J
Muñoz
Jorge
J
Coullin
Philippe
P
Danglot
Giséle
G
Tuñon
Teresa
T
Martínez-Peñuela
José María
JM
Rivera
José María
JM
Burgos
Juan J
JJ
Bernheim
Alain
A
Castresana
Javier S
JS
D000373:Agglutinins / Q000235:genetics*; D002135:Calcium-Binding Proteins; D045744:Cell Line, Tumor; D002528:Cerebellar Neoplasms / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D017931:DNA Primers; D004268:DNA-Binding Proteins; D017353:Gene Deletion; D015870:Gene Expression; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008527:Medulloblastoma / Q000235:genetics*; D018242:Neuroectodermal Tumors, Primitive / Q000235:genetics*; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015173:Supratentorial Neoplasms / Q000235:genetics*; D025521:Tumor Suppressor Proteins / Q000235:genetics*
D000373:Agglutinins; D002135:Calcium-Binding Proteins; C108174:DMBT1 protein, human; D017931:DNA Primers; D004268:DNA-Binding Proteins; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human