Genetic polymorphisms in NAT1, NAT2, GSTM1, GSTP1 and GSTT1 and susceptibility to colorectal cancer among Filipinos

@#Objectives. Polymorphisms in metabolic genes which alter rates of bioactivation and detoxification have been shown to modulate susceptibility to colorectal cancer. This study sought to evaluate the colorectal cancer risk from environmental factors and to do polymorphism studies on genes that code for Phase I and II xenobiotic metabolic enzymes among Filipino colorectal cancer patients and matched controls. Methods. A total of 224 colorectal cancer cases and 276 controls from the Filipino population were genotyped for selected polymorphisms in GSTM1, GSTP1, GSTT1, NAT1 and NAT2. Medical and diet histories, occupational exposure and demographic data were also collected for all subject participants.Results. Univariate logistic regression of non-genetic factors identified exposure to UV (sunlight) (OR 1.99, 95% CI: 1.16-3.39) and wood dust (OR 2.66, 95% CI: 1.21-5.83) and moldy food exposure (OR 1.61, 95% CI:1.11-2.35) as risk factors; while the NAT2*6B allele (recessive model OR 1.51, 95% CI :1.06-2.16; dominant model OR 1.87, 95% CI: 1.05-3.33) and homozygous genotype (OR 2.19, 95% CI: 1.19-4.03) were found to be significant among the genetic factors. After multivariate logistic regression of both environmental and genetic factors, only UV radiation exposure (OR 2.08, 95% CI: 1.21-3.58) and wood dust exposure (OR 2.08, 95% CI: 0.95-5.30) remained to be significantly associated with increasing colorectal cancer risk in the study population.Conclusion. This study demonstrated that UV sunlight and wood dust exposure play a greater role in influencing colorectal cancer susceptibility than genotype status from genetic polymorphisms of the GST and the NAT` genes.

The prevalence of CYP2D6 Gene Polymorphisms among Filipinos and their use as biomarkers for lung cancer risk

Objectives@#The highly polymorphic nature of the CYP2D6 gene and its central role in the metabolism of commonly used drugs make it an ideal candidate for pharmacogenetic screening. This study aims to determine the prevalence of CYP2D6 polymorphisms among Filipinos and their association to lung cancer. @*Method@#Forty seven single nucleotide polymorphisms (SNPs) of the CYP2D6 gene were genotyped from DNA samples of 115 cases with lung cancer and age- and sex-matched 115 controls. @*Results@#Results show that 18 out of 47 polymorphisms have significant genotypic variability (>1% for at least 2 genotypes). No variant is associated with lung cancer. However, rs1135840, rs16947 and rs28360521, were found to be highly variable among Filipinos. @*Conclusion@#This study demonstrated that CYP2D6 polymorphisms are present among Filipinos, which, although not found to be associated with lung cancer, can be useful biomarkers for future pharmacogenetic studies. The SNP rs16947 is found to be associated with cancer and timolol-induced bradycardia; the SNP rs1135840, on the other hand, is only shown to be linked with cancer. The genetic variant rs28360521 is known to be associated with low-dose aspirin-induced lower gastrointestinal bleeding.

Profiles and prevalence of breast cancer in Negros Occidental from 2000 to 2008

Background: Breast cancer is the most common neoplasm afflicting women worldwide. In Negros Occidental, it comprises 21% of all cancers. From the cancer registry data, this study was intended to show the clinical profile of these patients with regard to established risk factors and, to determine prevalence rate of breast cancer in specific localities and the province of Negros Occidental. Objective: To determine the incidence and prevalence rates of breast cancer in Negros Occidental from 2000 to 2008 and describe patients’ clinical profile. Research Design: Cross-sectional descriptive Subject: All Breast Cancer patients registered with the cancer registry in Negros Occidental from 2000 – 2008. Results: There were 1,242 patients registered with the Negros Occidental Cancer Registry from 2000 up to the year 2008. All were included in the study. Majority were females with age at diagnosis ranging from 20 to 89 years. Seventy-one percent had no family history of cancer. Postmenopausal women constitute 49.8%. The bulk of female patients were lifelong non-smokers (78.7%). The most common histopathologic diagnosis was infiltrating ductal carcinoma (87.9%). A third of patients were Stage II-A at the time of diagnosis. Of these, 37.8% opted to undergo surgery as primary intervention. Majority have unknown estrogen and progesterone receptor status (80.3%). Bacolod City consistently had the most number of breast cancer cases over the past eight years (39.2%). The prevalence of breast cancer in Negros Occidental, as of 2008 is 51.81 per 100,000 population. Conclusion: Gender, age and positive family history as risk factors reflect the current trends in breast cancer worldwide as noted in available registry records. Other factors like ages at menarche, at first full term pregnancy and at menopause, fat intake, passive smoking, BMI and alcohol abuse should be noted and included in the database.