Frequency and Association Of GSTM1 and GSTT1 Gene Polymorphisms with Survival in Breast Cancer Patients.

Objective: Glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) are the key detoxification enzymes of xenobiotics, including chemotherapeutic drugs. The deletion polymorphisms of GSTM1 and GSTT1 genes are associated with reduced enzyme activity that influenced clinical outcomes of chemotherapeutic agents in breast cancer. However, there is limited information among Thai patients.

Doxorubicin-conjugated dexamethasone induced MCF-7 apoptosis without entering the nucleus and able to overcome MDR-1-induced resistance.

Background: Doxorubicin (DOX) is the most widely used chemotherapeutic agent that has multimodal cytotoxicity. The main cytotoxic actions of DOX occur in the nucleus. The emergence of drug-resistant cancer cells that have the ability to actively efflux DOX out of the nucleus, and the cytoplasm has led to the search for a more effective derivative of this drug.

Association between ERCC1 Polymorphism and the Risk and Clinicopathological Features of Breast Cancer in Thai Women in the Lower Northeastern Region.

Background: Breast cancer is a major public health problem around the world, including Thailand and it has the highest ranking among female cancer. Currently, the diversity or polymorphism of ERCC1 gene (excision repair cross-complementary group 1 gene or ERCC1) was reported to associate with an increased risk of breast cancer. This study aims to investigate the relationship between ERCC1 polymorphism and the breast cancer risk in the lower northeastern region women of Thailand.

Clinicopathological significance of BRCA1 promoter hypermethylation in Thai breast cancer patients.

Breast cancer susceptibility gene 1 (BRCA1), mapped on chromosome 17q21, is implicated in the mechanisms of cellular DNA repair. Inactivation of this gene is involved in the development of many human cancers, including breast cancer. This study aimed to investigate the prognostic value of BRCA1 promoter hypermethylation and expression in breast cancer cases.

Alu methylation in serum from patients with nasopharyngeal carcinoma.

Background: Nasopharyngeal carcinoma (NPC) is a common cancer in Southern China and Southeast Asia. Alu elements are among the most prevalent repetitive sequences and constitute 11% of the human genome. Although Alu methylation has been evaluated in many types of cancer, few studies have examined the levels of this modification in serum from NPC patients.

Hypermethylation of suppressor of cytokine signaling 1 in hepatocellular carcinoma patients.

Hepatocellular carcinoma (HCC), the most common primary hepatic tumor, is highly prevalent in the Asia-Pacific region, including Thailand. Many genetic and epigenetic alterations in HCC have been elucidated. The aim of this study was to determine whether aberrant methylation of the suppressor of cytokine signaling 1 gene (SOCS1) occurs in HCCs.

LINE-1 methylation in the peripheral blood mononuclear cells of cancer patients.

Background: Recently, we classified LINE-1 loci according to their methylation statuses and found that the percentage of hypomethylated LINE-1 loci ((u)C(u)C) can differentiate between the peripheral blood mononuclear cells (PBMCs) of oral cancer patients and normal controls with a higher specificity and sensitivity than overall methylation levels. Here, we evaluated the LINE-1 methylation levels and patterns in PBMCs from patients with cancers of the nasopharynx, lung, liver, bile duct, breast and colon.

Methods: Combined Bisulfite Restriction Analysis (COBRA) of LINE-1 loci was performed to examine the LINE-1 methylation statuses of PBMCs from 216 cancer patients with 6 different types of cancer compared with 144 normal controls.

Epstein-Barr virus strains defined by the latent membrane protein 1 sequence characterize Thai ethnic groups.

Epstein-Barr virus (EBV) is ubiquitous in the human population and seroepidemiological studies have revealed that more than 90% of adults are infected with the virus in Thailand. It has been suggested that latent membrane protein 1 (LMP1) variants may differ in their tumorigenicity and geographical localization. The distribution of LMP1 variants of EBV in the Thai population was studied.

Real-time PCR assay for rapid detection of GSTM1 polymorphism in nasopharyngeal carcinoma patients.

Nasopharyngeal carcinoma (NPC) is a common public health problem in Thailand. Glutathione S-transferase M1 gene deletion (GSTM1 null genotype) carriers have been reported to be at increased risk and therefore this parameter is a potential marker for screening of NPC high-risk individuals. However, the conventional polymerase chain reaction (C-PCR) assay commonly used for GSTM1 null genotype detection is not suitable for mass screening since it is inconvenient, time consuming and unsafe due to the use of a toxic chemical.

Association between EBNA2 and LMP1 subtypes of Epstein-Barr virus and nasopharyngeal carcinoma in Thais.

Background: Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy that is common in Thailand. The association of the EBV nuclear antigen 2 gene (EBNA2) and the latent membrane protein 1 gene (LMP1) with NPC is unclear.

Objective: To determine the association between EBNA2 and LMP1 subtypes of EBV and NPC in Thais.

Cytochrome P450 2A6 polymorphism in nasopharyngeal carcinoma.

Nitrosamine has been identified as a carcinogen for nasopharyngeal carcinoma (NPC). Here, we investigated if a nitrosamine metabolizing gene, cytochrome P450 2A6 (CYP2A6) played an important role in NPC development. Relationships between the disease and the CYP2A6 were studied in 74 NPC patients and 137 age-matched healthy controls by using PCR-RFLP assay to distinguish between a wide type allele, *1A, and two mutant alleles, *1B and *4C.

Glutathione S-transferase M1 gene polymorphism in Thai nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a serious health problem in Thailand. It is caused by the combined effects of Epstein-Barr virus (EBV), carcinogens and genetic susceptibility. The glutathione S-transferase M1 gene (GSTM1) encodes a phase II enzyme responsible for detoxifying carcinogenic electrophiles.

Recent origin and cultural reversion of a hunter-gatherer group.

Contemporary hunter-gatherer groups are often thought to serve as models of an ancient lifestyle that was typical of human populations prior to the development of agriculture. Patterns of genetic variation in hunter-gatherer groups such as the Kung and African Pygmies are consistent with this view, as they exhibit low genetic diversity coupled with high frequencies of divergent mtDNA types not found in surrounding agricultural groups, suggesting long-term isolation and small population sizes. We report here genetic evidence concerning the origins of the Mlabri, an enigmatic hunter-gatherer group from northern Thailand.

The p53 codon 72 polymorphism in Thai nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a serious cancer in Thailand. To address on the genetic risk factor for NPC, we investigated association between the p53 codon 72 polymorphism (Pro/Arg) and NPC susceptibility in the Thai. The genotype frequency of this polymorphism in 102 NPC patients and 148 age-matched healthy controls was determined by using a PCR-RFLP assay.

Significance of plasma IgA and IgG antibodies to Epstein-Barr virus early and viral capsid antigens in Thai nasopharyngeal carcinoma.

Epstein-Barr virus (EBV) is an important causal factor of human nasopharyngeal carcinoma (NPC). High levels of serum IgA and IgG antibodies to EBV early and viral capsid antigens (IgA/EA, IgA/VCA, IgG/EA and IgG/VCA) have been reported in NPC patients. Since specific serum IgA/EA, IgA/VCA and IgG/EA are claimed to be useful serological markers for NPC.

Anthropological implication of the SDF1-3'A allele distribution in Southeast Asia and Melanesia.

The distribution of the SDF1-3'A allele among 1848 individuals in Southeast Asia and Melanesia was studied with the polymerase chain reaction-restriction fragment length polymorphism assay. The SDF1-3'A allele frequency in the populations of mainland Southeast Asia ranged from 0.0 to 0.

Prevalence of hepatitis B and C virus infection in rural ethnic populations of Northern Thailand.

Background: In Thailand, the population is composed of multiethnic stocks. However, many epidemiological studies on HBV and HCV have focused on blood donors with Thai and/or Chinese ethnic background. Available information on HBV and HCV infections among ethnic minorities in Thailand is limited.