Genetic polymorphisms associated with breast cancer in malaysian cohort.

Genome-wide association studies have discovered multiple single nucleotide polymorphisms (SNPs) associated with the risk of common diseases. The objective of this study was to demonstrate the replication of previously published SNPs that showed statistical significance for breast cancer in the Malaysian population. In this case-control study, 80 subjects for each group were recruited from various hospitals in Malaysia. A total of 768 SNPs were genotyped and analyzed to distinguish risk and protective alleles. A total of three SNPs were found to be associated with increased risk of breast cancer while six SNPs showed protective effect. All nine were statistically significant SNPs (p ≤ 0.01), five SNPs from previous studies were successfully replicated in our study. Significant modifiable (diet) and non-modifiable (family history of breast cancer in first degree relative) risk factors were also observed. We identified nine SNPs from this study to be either conferring susceptibility or protection to breast cancer which may serve as potential markers in risk prediction.

Role of genetic & environment risk factors in the aetiology of colorectal cancer in Malaysia.

BACKGROUND & OBJECTIVES: Colorectal cancer (CRC) is second only to breast cancer as the leading cause of cancer-related deaths in Malaysia. In the Asia-Pacific area, it is the highest emerging gastrointestinal cancer. The aim of this study was to identify single nucleotide polymorphisms (SNPs) and environmental factors associated with CRC risk in Malaysia from a panel of cancer associated SNPs. METHODS: In this case-control study, 160 Malaysian subjects were recruited, including both with CRC and controls. A total of 768 SNPs were genotyped and analyzed to distinguish risk and protective alleles. Genotyping was carried out using Illumina's BeadArray platform. Information on blood group, occupation, medical history, family history of cancer, intake of red meat and vegetables, exposure to radiation, smoking and drinking habits, etc was collected. Odds ratio (OR), 95% confidence interval (CI) were calculated. RESULTS: A panel of 23 SNPs significantly associated with colorectal cancer risk was identified (P<0.01). Of these, 12 SNPs increased the risk of CRC and 11 reduced the risk. Among the environmental risk factors investigated, high intake of red meat (more than 50% daily proportion) was found to be significantly associated with increased risk of CRC (OR=6.52, 95% CI :1.93-2.04, P=0.003). Two SNPs including rs2069521 and rs10046 in genes of cytochrome P450 (CYP) superfamily were found significantly associated with CRC risk. For gene-environment analysis, the A allele of rs2069521 showed a significant association with CRC risk when stratified by red meat intake. INTERPRETATION & CONCLUSIONS: In this preliminary study, a panel of SNPs found to be significantly associated with CRC in Malaysian population, was identified. Also, red meat consumption and lack of physical exercise were risk factors for CRC, while consumption of fruits and vegetables served as protective factor.

Association of genetic and non-genetic risk factors with the development of prostate cancer in Malaysian men.

There is growing global interest to stratify men into different levels of risk to developing prostate cancer, thus it is important to identify common genetic variants that confer the risk. Although many studies have identified more than a dozen common genetic variants which are highly associated with prostate cancer, none have been done in Malaysian population. To determine the association of such variants in Malaysian men with prostate cancer, we evaluated a panel of 768 SNPs found previously associated with various cancers which also included the prostate specific SNPs in a population based case control study (51 case subjects with prostate cancer and 51 control subjects) in Malaysian men of Malay, Chinese and Indian ethnicity. We identified 21 SNPs significantly associated with prostate cancer. Among these, 12 SNPs were strongly associated with increased risk of prostate cancer while remaining nine SNPs were associated with reduced risk. However, data analysis based on ethnic stratification led to only five SNPs in Malays and 3 SNPs in Chinese which remained significant. This could be due to small sample size in each ethnic group. Significant non-genetic risk factors were also identified for their association with prostate cancer. Our study is the first to investigate the involvement of multiple variants towards susceptibility for PC in Malaysian men using genotyping approach. Identified SNPs and non-genetic risk factors have a significant association with prostate cancer.

Influences of multiple genetic polymorphisms on ovarian cancer risk in Malaysia.

OBJECTIVE: The identification of high-risk individuals can help to improve early cancer detection and patient survival. Risk assessment, however, can only be accomplished if the risk factors are known. To date, the genetic risk factors for ovarian cancer, other than mutations in the BRCA1/2 genes, have never been systematically explored in Malaysia. The present study aims to identify from a panel of cancer-associated single-nucleotide polymorphisms (SNPs), those associated with ovarian cancer risk in Malaysia. METHODS: A total of 768 SNPs associated with various cancers among Asians were identified through a search of the relevant literature, and these SNPs were then screened for their association with ovarian cancer. A total of 160 Malaysian subjects were recruited for the study, including both ovarian cancer patients and controls. Genotyping was carried out using Illumina BeadArray platform. RESULTS: A panel of 45 SNPs that are significantly (p<0.05) associated with ovarian cancer risk was identified. These ovarian cancer-associated SNPs were located in genes implicated in various pathways of carcinogenesis. Of these 45 SNPs, 5 have been previously associated with either ovarian cancer risk or survival. CONCLUSION: This study has identified a panel of 45 SNPs that are significantly associated with ovarian cancer in a Malaysian population.

Identification of genetic and non-genetic risk factors for nasopharyngeal carcinoma in a Southeast Asian population.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is endemic in Southern Chinese and Southeast Asian populations. Geographical and ethnic clustering of the cancer is due to genetic, environmental, and lifestyle risk factors. This case-control study aimed to identify or confirm both genetic and non-genetic risk factors for NPC in one of the endemic countries, Malaysia. MATERIALS AND METHOD: A panel of 768 single-nucleotide polymorphisms (SNPs) previously associated with various cancers and known non-genetic risk factors for NPC were selected and analyzed for their associations with NPC in a case-control study. RESULTS: Statistical analysis identified 40 SNPs associated with NPC risk in our population, including 5 documented previously by genome-wide association studies (GWAS) and other case-control studies; the associations of the remaining 35 SNPs with NPC were novel. In addition, consistent with previous studies, exposure to occupational hazards, overconsumption of salt-cured foods, red meat, as well as low intake of fruits and vegetables were also associated with NPC risk. CONCLUSIONS: In short, this study confirmed and/or identified genetic, environmental and dietary risk factors associated with NPC susceptibility in a Southeast Asian population.