MATERIALS AND METHODS: We selected 157 NPC cases and 136 controls from two hospitals in Kuala Lumpur, Malaysia for this study. The polymorphisms studied were genotyped by PCR-RFLP assay and allele and genotype frequencies, haplotype and linkage disequilibrium were determined using SNPstat software.
RESULTS: For the XPD Lys751Gln polymorphism, the frequency of the Lys allele was higher in cases than in controls (94.5% versus 85.0%). For the XRCC1 Arg280His polymorphism, the frequency of Arg allele was 90.0% and 89.0% in cases and controls, respectively and for XRCC1 Arg399Gln the frequency of the Arg allele was 72.0% and 72.8% in cases and controls respectively. All three polymorphisms were in linkage disequilibrium. The odds ratio from haplotype analysis for these three polymorphisms and their association with NPC was 1.93 (95%CI: 0.90-4.16) for haplotype CGC vs AGC allele combinations. The global haplotype association with NPC gave a p-value of 0.054.
CONCLUSIONS: Our study provides an estimate of allele and genotype frequencies of XRCC1Arg280His, XRCC1 Arg399Gln and XPD Lys751Gln polymorphisms in the Malaysian population and showed no association with nasopharyngeal cancer.
MATERIALS AND METHODS: The cancer registry from 1986 to 2014 maintained by the State Laboratory was retrospectively reviewed. The age standardized rates (ASR) and the age specific incidence rates (ASIR) were calculated. Non NPC tumors were excluded from the study.
RESULTS: Altogether, there were a total of 450 NPC cases diagnosed accounting for 4.4% of all total cancer cases over the study period, declining from 10.3% in 1986-1990 to 2.3% in 2011-2014. The most common tumor type was the undifferentiated carcinoma (96.4%). The case characteristics were mean age 50.4 ± 14.4 years old, male 69%, and predominately Malays 74.4%, followed by Chinese 16.7%. The mean age of diagnosis increased over the study period from 45.6 ± 17.1 years (1986-1989) to 54.1 ± 12.5 years (ANOVA, p<0.01 for trend). There were no differences in the mean age of diagnosis between the ethnic groups or genders. The ASR showed a declining trend from 11.1 per 100,000 in 1986-1990 to 5.95 per 100,000 in 2011-2014, similar trends been observedfor both genders. Among the age groups, declining trends were seen in all the other age groups apart from the >70 years group. The overall ASRs for the Malays and Chinese were 7.92/100,000 and 8.83/100,000 respectively, both showing declining trends.
CONCLUSIONS: The incidence of NPC in Brunei Darussalam is comparable to rates reported from Singapore and Malaysia, but higher than rates reported from the other Southeast Asian nations. Unlike higher rates reported for Chinese compared to the Malays in other countries, the rates between the Malays and Chinese in our study was comparable. Importantly, the ASR is declining overall and for both genders and ethnic groups.