William Y. W. Au

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A deletion polymorphism in glutathione S-transferase theta (GSTT1) gene was recently discovered in humans. Similar to the GSTM1 gene, GSTT1 is also recognized as a risk modifier in exposed populations. To evaluate the role of genetic polymorphism in health effects, the combined genetic polymorphism of different genes should be taken into consideration. In(More)
A major barrier to understanding the role of polymorphic DNA repair genes for environmental cancer is that the functions of variant genotypes are largely unknown. Using our cytogenetic challenge assays, we conducted an investigation to address the deficiency. Using X-rays or ultraviolet (UV) light, we irradiated blood lymphocytes from 80 nonsmoking donors(More)
We have previously investigated the role of polymorphic chemical metabolizing genes in the susceptibility to the development of lung cancer using 110 primary lung cancer patients and 119 matched smoker controls. Together with data from the present study on DNA repair genes, we did not observe significant associations between any single variant genotype for(More)
DNA repair capacity is essential in maintaining cellular functions and homeostasis. However, the repair capacity can be altered based on DNA sequence variations in DNA repair genes and thus may cause cancer susceptibility. We investigated associations between polymorphisms in DNA repair genes and oral squamous cell carcinoma (OSCC) in a Thai population.(More)
Exposure to pesticides remains a major environmental health problem. Health risk from such exposure needs to be more precisely understood. We conducted three different cytogenetic assays to elucidate the biological effects of exposure to mixed pesticides in 20 Costa Rica farmers (all nonsmokers) compared with 20 matched controls. The farmers were also(More)
Cigarette smoking is generally believed to be responsible for a substantial number of human health problems. However, the causal relationship between smoking, the induction of biological effects and the extent of health problems among smokers have not been fully documented. Using the recently developed lymphocyte micronucleus (MN) assay, we have evaluated(More)
Inheritance of variant DNA repair genes is believed to influence individual susceptibility to the development of environmental cancer. However, the validity of the belief is dependent upon understanding the functions of the variant genes. Consequently, a variety of studies have been conducted to investigate the functions of variant DNA repair genes, e.g.(More)
From a review of decades of intensive biomarker research and prospective validation studies, it becomes clear that only a limited number of biomarkers can be used to provide reliable documentation of excessive exposure to environmental mutagenic agents, expression of detrimental biological effects from the exposure and increased risk for cancer. These(More)
Aquaculture is one of the fastest growing food-producing sectors, supplying approximately 40% of the world's fish food. Besides such benefit to the society, the industry does have its problems. There are occupational hazards and safety concerns in the aquaculture industry. Some practices have caused environmental degradation. Public perception to farmed(More)
The codon 72 polymorphism of the p53 tumor suppressor gene has been investigated extensively for its association with various cancers around the world. However, its influence has not been elucidated in the Thai population. Therefore, a case-control study with 97 patients and 97 matched controls was conducted to elucidate the association between the(More)