Dr Ng Khoon Leong

Thyroid cancer incidence in iodine-sufficient areas such as Malaysia is on the rise. Thyroid cancer is more common in women than in men. From 2007-2011, the incidence of thyroid cancer among Malaysian women was approximately 1 in 35,000. Oxidative stress is believed to be one of the contributing factors. Preliminary proteomics analyses in our laboratory showed that proteins of altered abundance in serum of PTC patients with benign MNG background differed from those without the MNG background. This suggests that more than one mechanism is linked to PTC. In addition, a clinical case study recently reported by our group showed the presence of a somatic BRAFV600E mutation in the malignant area of the thyroid gland of a patient. However the mutation was absent in the benign area of the gland. Differential expression patterns of thyroid-related genes were also detected in the benign and malignant area of the thyroid. This case indicates that the progression of benign to malignant thyroid cancer with an MNG background may be associated with H2O2-related oxidative stress. The oxidative imbalance could be linked to the overproduction of H2O2 by DUOX2 and NOX4 or by impaired antioxidant enzymes activities. Our preliminary study also showed significant differences in genotype and haplotype frequencies for two novel SNPs; rs752779 (p = 0.03) and rs1970951 (p = 0.05) among the MNG, PTC, and FTC groups. My group is expanding our study by recruiting a bigger sample size to confirm the preliminary findings and to determine their risk or protective role in thyroid cancers. We are also studying if malignant PTC can develop from benign MNG and if this transformation is linked to H2O2-related oxidative imbalance.