GDF15 and cancer: The demonstration of GDF-15 mRNA by RT-qPCR technique with the FNA and frozen tissue material procured from the postoperative thyroidectomy specimens of the pathologic thyroid nodules and the consistently elevated GDF-15 mRNA levels in all malignant thyroid nodules including FTC, FVPTC, and CPTC strongly support the role of GDF-15 as a potent molecular marker for distinguishing benign vs. malignant thyroid nodules, in general, and benign vs. malignant follicular-patterned lesions, in particular.