TPO and thyroid tumor: Regarding coding RNAs, Yang et al. have developed a multiplex approach for the quantification of circulating transcripts in thyroid tumor patients, identifying 4 circulating RNAs (thyroid peroxidase TPO, TG, glial cell line-derived neurotrophic factor family receptor alpha-2 GFRA2, and iodotyrosine deiodinase IYD) in the plasma of thyroid cancer patients, among which TPO transcript resulted in the most promising marker to estimate residual disease [198].