title: Ethnicity delineates different genetic pathways in malignant glioma.
abstract: In the United States and the San Francisco Bay Area, whites are nearly twice as likely as non-whites to develop brain cancer. To test whether prevalence and types of alterations in the p53 pathway in brain tumor development may explain some of this difference in risk, we have analyzed the p53 status of astrocytic gliomas from a population-based sample of cases within our San Francisco Bay Area Adult Glioma Study. We identified mutations in exons 5-8 of p53 using DNA extracted from formalin-fixed paraffin-embedded tissue blocks from 146 whites and 26 non-whites with astrocytic glioma by PCR-single-strand conformation polymorphism and direct sequencing. Tumor P53 protein (TP53) immunohistochemistry (IHC) available for 164 of these cases showed that tumors from 50% (13 of 26) of non-whites and 32% (44 of 138) of whites contained intense IHC staining for TP53, indicating persistence of TP53 protein. Irrespective of IHC status, tumors from 42% (11 of 26) of non-whites versus 13% (19 of 146) of whites contained p53 mutations (age/gender-adjusted odds ratio, 5.7; 95% confidence interval, 2.2-15.1; P = 0.0004). Patients with p53 mutation-positive tumors were also significantly younger than patients with mutation-negative tumors and somewhat more likely to be female. A higher proportion of tumors from non-whites than from whites had transition mutations, but there were similar proportions of transversion mutations in tumors from whites and non-whites. Whites and non-whites also had similar proportions of tumors with p53 mutations that stained intensely for TP53 (78 and 82%, respectively). Because whites have higher risk for glioma than non-whites in this population, that the gliomas from whites were less likely than those from non-whites to have p53 mutation suggests that whites may be more likely than non-whites to be at risk for the more common type of astrocytic gliomas, which do not contain p53 mutations.
authors.affiliation: Laboratory for Molecular Epidemiology, Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, CA 94143, USA.
authors.forename: P
authors.initials: P
authors.lastname: Chen
authors.forename: K
authors.initials: K
authors.lastname: Aldape
authors.forename: J K
authors.initials: JK
authors.lastname: Wiencke
authors.forename: K T
authors.initials: KT
authors.lastname: Kelsey
authors.forename: R
authors.initials: R
authors.lastname: Miike
authors.forename: R L
authors.initials: RL
authors.lastname: Davis
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: A
authors.initials: A
authors.lastname: Kesler-Diaz
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Wrensch
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000235:genetics* / Q000378:metabolism; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012737:Sex Factors; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D016159:Tumor Suppressor Protein p53