Characterisation of molecular alterations in microdissected archival gliomas.
Classification of gliomas according to their molecular characteristics may be important in future histopathological diagnosis. However, gliomas frequently display heterogeneity at the histological, biological and molecular level. In this study of archival diagnostic gliomas, precision microdissection was used to enrich samples in the most malignant cells or to investigate intratumoural histological heterogeneity. Analysis of tumour samples microdissected from the most aggressive regions, representative of the histopathological diagnosis, revealed PTEN mutations in 4/14 anaplastic astrocytomas, 4/13 glioblastomas and 1 gliosarcoma, but not in 19 low-grade gliomas. Using a novel PCR procedure and direct sequence analysis of the entire coding sequence, TP53 mutations were detected in 1/3 pilocytic astrocytomas, 3/13 astrocytomas, 4/14 anaplastic astrocytomas, 5/13 glioblastomas and 1 gliosarcoma. All but one of the tumours with TP53 mutation showed p53 immunopositivity, but 5 low-grade and 10 high-grade gliomas had p53 protein nuclear accumulation in the absence of detectable mutation. p53 status was unrelated to p21 expression. Neither PTEN nor TP53 mutations influenced the proliferative index or microvessel density of high-grade astrocytomas. Unusual findings include: TP53 mutation in a juvenile pilocytic astrocytoma; TP53 and PTEN mutations in a de novo glioblastoma, a gliosarcoma with identical mutations in gliomatous and sarcomatous components, and an infratentorial anaplastic astrocytoma with an earlier supratentorial grade II astrocytoma bearing the same TP53 mutation but not the PTEN mutation or loss of heterozygosity (LOH) of 10q23. Similarly, the transition to high-grade histology was associated with acquisition of PTEN mutations and 10q23.3 LOH in two de novo high-grade tumours with regions of low-grade histology.
Walker
C
C
Clatterbridge Cancer Research Trust, J.K. Douglas Laboratories, Clatterbridge Hospital, Bebington, Wirral CH63 4JY, UK. carolw@ccrt.co.uk
Joyce
K A
KA
Thompson-Hehir
J
J
Davies
M P
MP
Gibbs
F E
FE
Halliwell
N
N
Lloyd
B H
BH
Machell
Y
Y
Roebuck
M M
MM
Salisbury
J
J
Sibson
D R
DR
Du Plessis
D
D
Broome
J
J
Rossi
M L
ML
D000293:Adolescent; D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D001932:Brain Neoplasms / Q000098:blood supply / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D002648:Child; D003062:Codon / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics; D066246:ErbB Receptors / Q000032:analysis; D005260:Female; D016158:Genes, p53; D005910:Glioma / Q000098:blood supply / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D008940:Mitotic Index; D020125:Mutation, Missense; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics; D009687:Nuclear Proteins; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis / Q000235:genetics; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000032:analysis; D051736:Proto-Oncogene Proteins c-mdm2; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D025521:Tumor Suppressor Proteins
C493956:CDKN1A protein, human; D003062:Codon; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004273:DNA, Neoplasm; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D066246:ErbB Receptors; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human