miRNA Expression Profiling in Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) is commonly diagnosed in Australia and has an increasing incidence; it is projected to be the 10th most commonly diagnosed cancer by the end of 20191. Fortunately it has a good outcome, with the mortality rate stable over the last 25 years at around 2%2. The challenge to the clinician is to determine the best diagnostic tools to aid in appropriate management of the disease. MicroRNA (miRNA) is an emerging tool in the diagnosis and management of cancers. We examined the expression of miRNAs in an Australian population with PTC, both those known to have altered expression and novel miRNAs. Tissues of 30 subjects were collected, 18 from whom we also had access to serum. The miRNAs were studied in thyroid tumour and normal tissue, lymph nodes and serum. MiRNAs mir-10b, miR-31, miR-100, miR-146b, miR-221, miR-222 and let-7d were studied, with miR-16, RNU48 and Cel-39 used as controls. Our study demonstrated significantly elevated expression of miRs -146b, -221 and -222 in tumour tissue vs normal tissue and a significantly decreased expression of miR-10b. We also showed that handling of serum samples has a significant impact on the results when analysing miRNAs, due to the effect of haemolysis. 1. Ferlay J SI, Ervik M, et al. GLOBOCAN 2012 v1.0, Cancer incidence and mortality worldwide: IARC cancerbase no. 11 In. Lyon, France: International Agency for Research on Cancer; 2013. 2. Siegel R, Ma J, Zou Z, Jemal A. Cancer statistics, 2014. CA Cancer J Clin. 2014;64(1):9-29