ABSTRACT
Nasopharyngeal carcinoma (NPC) is a common cancer and a serious public-health problem in Thailand. Glutathione S-transferase Mu1 and Theta1 gene (GSTM1 and GSTT1) are involved in the prevention of cancer, by encoding GSTM1 and GSTT1 enzymes to detoxify various electrophiles derived from environmental carcinogens. GSTM1 and GSTT1 polymorphisms are reportedly associated with several malignancies and can be used as a genetic risk marker for cancer. Nevertheless, GSTM1 and GSTT1 polymorphism detection using the conventional polymerase chain reaction (C-PCR) assay is complicated and time-consuming, and thus unsuitable for mass screening. A faster multiplex PCR (M-PCR) assay has been developed to help overcome these problems. The present study aimed to establish the M-PCR assay for GSTM1 and GSTT1 polymorphism detection in NPC patients, and confirm the results of the new assay with the C-PCR assay. Eighty DNA samples, extracted from the peripheral blood leukocytes of Thai NPC patients, were examined for GSTM1 and GSTT1 polymorphism [GSTM1 normal genotype (GSTM1+), GSTM1 null genotype (GSTM1-), GSTT1 normal genotype (GSTT1+), and GSTT1 null genotype (GSTT1-)] by M-PCR and C-PCR assays. The GSTM1 and GSTT1 polymorphism-detection results in all NPC cases by M-PCR assay agreed with the C-PCR assay ( = 1.0). In addition, the M-PCR assay was a simple, faster, and less costly method for GSTM1 and GSTT1 polymorphism detection than the C-PCR assay. The present study suggests that GSTM1 and GSTT1 polymorphism detection by M-PCR assay is a reliable and suitable tool for screening high-risk NPC groups. (Thai Cancer J 2010;30:94-103)
ABSTRACT
Effects of chronic morphine exposure to monkeys on humoral immune status with reference to serum cortisol levels were studied. Male cynomolgus monkeys (Macaca fascicularis) were exposed to morphine daily (3mg/kg; n=3, 6mg/kg; n=3) and their blood spfecimens were collected every week to test serum levels of immunoglobulins and cortisol. Serum cortisol levels decreased initially and then elevated gradually. Levels of immunoglobulins, IgG and IgM, in monkeys exposed to large dose (6mg/kg) of morphine was lower than that in monkeys with small dose (3mg/kg). An elevation in Igs levels were obsereved in monkeys treated with the small dose of morphine but consistent reduction in the serum IgG levels was observed in monkeys exposed to morphine with the large dose. Therefore, chronic exposure to the large dose of morphine may lead to immunosuppression and result in disease prone status.
ABSTRACT
Oral cavity cancer (OCC) is a serious malignant disease in Thailand, particularly in the South, including Suratthani province, with a trend to increase in the number of its death yearly. However, patients with early stages of OCC are treatable. Hence, a mass screening for early stages of OCC patients without cancer-related symptoms is urgent. GSTM1 gene (GSTM1) that produced enzyme for detoxification of carcinogens has been reported to be polymorphic and associated with the risk of several cancer developments. The purpose of this study is to investigate the association between GSTM1 polymorphisms and the risk of OCC development in Suratthani province population. The frequency of GSTM1 genotypes [GSTM1 normal (GSTM1+) and GSTM1 null genotype (GSTM1-)] was detected in DNA extracted from peripheral white blood cells of 200 cases of OCC patients and 200 healthy controls using the polymerase chain reaction (PCR) assay. Overall, the frequency of GSTM1 genotypes between OCC and healthy control groups was significantly different (P \< 0.001). Individuals with GSTM1- had increased risk about 1.95-fold for OCC development as compared with those GSTM1+ [Odds ratio (OR) = 1.95, 95% confidence interval = 1.31-2.90]. In addition, GSTM1 polymorphism was found to be associated with an increased risk of OCC development in cigarette smokers, alcohol drinkers, and betel-nut chewers. In conclusion, the findings of this study suggest that GSTM1 polymorphism is associated with the risk of OCC development and the GSTM1- is the key factor for increasing the risk of OCC. Therefore, the detection of GSTM1 polymorphism is a useful tool in screening for the high-risk group that may be lead to identification of early stages of OCC in population who reside in Suratthani province.
ABSTRACT
Oral cancer is a serious malignant disease that caused vastly losses in Thailand annum. The potential risk factor for predicting and screening of high-risk populations that developed early stage oral cancer followed by immediately intensive counseling and efficiency treatment is an important strategy to control this harmful cancer. To address on the genetic risk factor for oral cancer was investigated. The association between the p53 codon 72 gene polymorphism and oral cancer susceptibility in Thai people. The frequency of p53 codon 72 gene polymorphism (Arginine/Arginine, Arginine/Proline and Proline/Proline genotypes) in 80 oral cancer patients, 80 chronic oral disease patients and 80 age-matched healthy controls was determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Statistically significant difference in the overall genotype frequencies between cases and controls comprising chronic oral disease patients and healthy controls was observed (p \< 0.05). Proline/Proline genotype carriers had 2.8-fold increased risk for oral cancer as compared with Arginine/Arginine genotype carriers (Odds ratio = 2.8, 95% confidence interval = 1.0-4.7). Among oral cancer patients, statistical significant difference in p53 genotype frequencies between clinical stages was also observed. The results in this study suggest that the p53 codon 72 gene polymorphism may associate with oral cancer susceptibility in Thai population, particularly the Proline/Proline genotype carrier. The suggestion is that the detection of p53 polymorphism may be a useful tool for screening of the high-risk group as well as prognosis of oral cancer in Thai people.
ABSTRACT
The P53 tumor suppressor gene (P53) is a key gene involved in cancer control by producing P53 protein to inhibit proliferation and enhance apoptosis of cancer cells. It has been reported that the polymorphism at the codon 72 on the exon 4 of P53 resulted in 3 different genotypes of the P53: Arginine/Arginine (Arg/Arg), Arginine/Proline (Arg/Pro) and Proline/Proline (Pro/Pro) genotypes, and found that individual with Pro/Pro of P53 codon 72 polymorphism had a higher risk for lung, bladder and nasopharyngeal cancers than those with Arg/Arg. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay used to detect P53 codon 72 polymorphism is not suitable for a mass screening since it is complicated, time-consuming and at risk for carcinogen exposure. Recently, real-time polymerase chain reaction-SimpleProbe probe (R-PCR-SP) assay has been suggested to be suitable for a mass screening of various genetic polymorphisms with a faster and safer way. The aim of this study is to detect P53 codon 72 polymorphism in Thai patients with lung cancer by the R-PCR-SP assay using SimpleProbe probe and melting curve analysis and the PCR-RFLP assay. The findings from these two methods were then comparable. Seventy DNA samples from peripheral blood leukocyte of lung cancer cases were recruited in this study. The results of P53 codon 72 polymorphism detected by the R-PCR-SP and the PCR-RFLP assays were completely accordant (κ=1.0, 95%CI = 1.0-1.0). The findings demonstrated 12 individuals with Arg/Arg, 41 cases with Arg/Pro and 17 cases with Pro/Pro. In addition, we found that the R-PCR-SP assay was a faster and safer method for detection of P53 codon 72 polymorphism than the PCR-RFLP assay. Results of the present study suggest that the R-PCR-SP assay with SimpleProbe probe and melting curve analysis may be a useful screening tool for detection of P53 codon 72 polymorphism in the high risk group of lung cancer in Thais.
ABSTRACT
Hepatocellular carcinoma (HCC) is a serious public health problem that caused vastly losses in Thailand annually. Recently, P53 codon 72 and GSTM1 polymorphisms have been found to associate with several cancers. The aim of this study is to investigate the association between P53 codon 72 and GSTM1 polymorphisms and risk of HCC development in Thais. The frequencies of P53 codon 72 genotypes (Arg/Arg, Arg/Pro and Pro/Pro genotypes) and GSTM1 genotypes (GSTM1+) and (GSTM1-) from 200 cases of HCC as well as 400 age-matched healthy control were analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR, respectively. In overall, the frequencies of P53 codon 72 polymorphism in HCC group were significantly different from those of healthy control. The Pro/Pro carriers had increased risk for HCC at 1.9-fold as compared to Arg/Arg carriers (OR=1.9; 95%CI=1.2-3.3). Similarly, the overall of frequencies of GSTM1 genotypes of GSTM1 polymorphism in HCC group were significantly different from those of healthy control. In addition, GSTM1- carriers had increased risk for HCC at 1.8-fold as compared to GSTM1+ carriers (OR=1.8; 95%CI=1.3-2.5). The results of this study suggest that P53 codon 72 and GSTM1 polymorphisms are associated with the increased risk of HCC and may be a useful tool for predicting and searching the high risk group of HCC in Thai population.
ABSTRACT
Nasopharyngeal carcinoma (NPC) is a multi-factorial disease caused by genetic, viral (Epstein Barr virus, EBV) and environmental factors. The elevation of IgA antibody titers against EBV viral capsid antigen (VCA) measured by indirect immunofluorescence assay (IFA) had been use as ‘gold standard’ for NPC diagnosis for over thirty years. However, IFA is unsuitable for mass screening among population since it is time-consuming, inconvenient to perform and difficult to standardize. To date, these difficulties of IFA have been solved by using recombinant protein-based enzyme-linked immunosorbent assay (ELISA). The EBV nuclear antigen 1 (EBNA1) is the only latent EBV antigen consistently expressed in NPC tissues. Recently, it has been found that IgA antibody against EBNA1 (IgA/EBNA1) measured by ELISA may be a useful marker for NPC and the early detection of this cancer. The purpose of this study is to evaluate the usefulness of IgA/EBNA1 from a commercial kit in Thai NPC cases. The concentration of serum IgA/EBNA1 was measured in 54 NPC patients and 122 age match healthy controls by using Sinoclone EBV IgA ELISA kit. The normal cut off value (mean+2SD) of serum IgA/EBNA1 showed a relative optical density (rOD) at 1.26 units. Serum IgA/EBNA1 level was positive in 52 (96.30%) out of 54 NPC patients and in 5 (4.10%) out of 122 healthy controls. NPC cases showed significantly higher serum IgA/EBNA1 level than healthy controls (P \< 0.001). In NPC patients, the serum IGA/EBNA1 level was increased with aggressiveness and advance stages of the disease. Detection of IgA/EBNA1 by Sinoclone EBV IgA ELISA kit in serum had a sensitivity, a specificity, positive predictive values and negative predictive values of 96.30, 95.90, 91.23 and 98.32%, respectively, for the diagnosis of NPC. The results of our study suggest that serum IgA/EBNA1 may be a suitable marker for diagnosis and prognosis of NPC in Thailand and that this test may be a useful addition to the panel of tests used for this purpose. Further studies are currently underway to evaluate the effectiveness of this marker as an early detection tool for NPC in Thailand.