We found that SLC5A5 expression was always lower in tumors than in normal adjacent counterparts as reported by other groups (6, 7, 37). We observed a significantly lower SLC5A5 expression in male gender patients, and in cases with vascular invasion, as well as a tendency to lower SLC5A5 expression in cases with extrathyroidal extension, but no differences were found in cases with and without lymph node metastases (Table 1). When we compare the results from our series to those from TCGA data, we confirmed that tumors express significantly less SLC5A5 compared to normal adjacent tissue, that SLC5A5 was not differently expressed in the presence or absence of lymph node metastases (at the time of diagnosis) and a significant lower SLC5A5 expression was found in tumors with extrathyroidal extension (moderate/advanced) compared to those without extrathyroidal extension (Fig. 2D). However, the differential expression of SLC5A5 between genders was not confirmed (Fig. 2B). Unfortunately, in TCGA database, there was no information about vascular invasion, so we could not validate this result in this large series.