Breast cancer is the cancer that most commonly affects women worldwide. This type of cancer is genetically complex, but is strongly linked to steroid hormone signaling systems. Because microRNAs act as translational regulators of multiple genes, including the steroid nuclear receptors, single nucleotide polymorphisms (SNPs) in microRNA genes can have potentially wide-ranging influences on breast cancer development. Thus, this study was conducted to investigate the relationships between six SNPs (rs6977848, rs199981120, rs185641358, rs113054794, rs66461782, and rs12940701) located in four miRNA genes predicted to target the estrogen receptor (miR-148a, miR-221, miR-186, and miR-152) and breast cancer risk in Caucasian Australian women. By using high resolution melt analysis (HRM) and polymerase chain reaction- restriction fragment length polymorphism (PCR–RFLP), 487 samples including 225 controls and 262 cases were genotyped. Analysis of their genotype and allele frequencies indicated that the differences between case and control populations were not significant for rs6977848, rs66461782, and rs12940701 because their p-values are 0.81, 0.93, and 0.1, respectively, which are all above the threshold value (p = 0.05). Our data thus suggests that these SNPs do not affect breast cancer risk in the tested population. In addition, rs199981120, rs185641358, and rs113054794 could not be found in this population, suggesting that these SNPs do not occur in Caucasian Australians.

-Introduction: Glucose-6-phosphate dehydrogenase (G6PD) deficiency which is caused by mutation on G6PD gene is the most common enzyme disorder in human. There have been 184 discovered mutations among which Viangchan [Val 291 Met] and Canton mutation [Arg 459 Leu] are the most common variants in Vietnamese. Due to the severity of this disease, several methods have been devised for diagnostics. However, time-consuming, low sensitivity and expensiveness are major problems of those techniques. Recently, High Resolution Melting (HRM) has been developed and proven to be an effective method for DNA genotyping, mutation scanning and sequence matching. Hence, in this study a multiplex HRM has been developed aiming at detecting these two mutations concurrently. Methods: At first, a singleplex HRM was designed for each mutation. Then, conditions for these singleplex assay were combined and optimized again in order to get the optimal condition for multiplex HRM. Results: This method showed a promising potential with a high accuracy, sensitivity, and specificity, it is impractial to continue developing this method because of the lack of controls. Conclusion: The optimized singleplex PCR-HRM in this study still can be used for single mutation detection and serve as the background to develop PCR-HRM for other G6PD mutations in Vietnamese-Kinh population.