Frequent loss of heterozygosity (LOH) and mutations of the tumor suppressor gene PTEN (phosphatase and tensin homologue deleted from chromosome 10) have been found in sporadic gliomas. The most documented regions of allelic losses include 9p21, 10q23-25 and 17p1 3 whereas PTEN aberrations are preferentially found in glioblastoma multiformes. This research aimed to detect the incidence of allelic losses on chromosomes 10q, 9p, 17p and 13q and mutations on exons 5, 6 and 8 of PTEN in malignant gliomas. Malignant glioma specimens obtained were classified histopathologically according to the WHO criteria. Each tumor was then subjected to polymerase chain reaction (PCR)-LOH analysis using microsatellite markers and single-stranded conformational polymorphism (SSCP) analysis. Twelve of 23 (52%) malignant glioma cases showed allelic losses whereas 7 of 23 (30%) samples showed aberrant band patterns and mutations of PTEN. Four of these cases showed LOH in 10q23 and mutations of PTEN. The data on LOH indicated the involvement of different genes in the genesis of glioma whereas mutations of PTEN indicated the role of PTEN tumor suppressor gene in the progression of glioma in Malay population.
Matched MeSH terms: Chromosomes, Human, 6-12 and X/genetics*
Incidence patterns indicated the prominent role of genetic factors in this type of cancer. A histocompatibility leukocyte antigen (HLA) profile of A2 and B-locus antigen, Singapore 2 (Sin 2), was identified. An association between these genes and increased risk for nasopharyngeal carcinoma (NPC), was confirmed. The risk was restricted to the "co-occurrence" of A2, B-Sin 2, suggesting that the genotype predisposing to the development of NPC was the A, B-Sin 2 haplotype. Similar associations were found to exist in Malaysian and Hong Kong Chinese so the A2, B-Sin 2 phenotype is a feature common to Asian Chinese in at least three locations. Preliminary HLA studies of medium NPC incidence in Tunisians and Malays indicated that patients with NPC of both ethnic types have altered HLA antigen profiles. If the findings of a locus-B antigen deficit in Tunisians and the role of A9 with B-locus antigens in Malays can be confirmed and clarified, the histocompatibility genetic hypothesis of NPC predisposition would be substantially strengthened.
Matched MeSH terms: Chromosomes, Human, 6-12 and X