Surprisingly, a complete absence of TRBP2 immunodetection during cell division and specifically mitosis (determined by α-Tubulin/microtubules immunostaining and mitotic spindle formation) was observed in all the examined cells of (a) the normal thyroid cell line NTHY-ori 3-1 (human thyroid follicular epithelial cells) and (b) the thyroid cancer cell lines TPC-1 (human papillary thyroid carcinoma) and ARO (human thyroid anaplastic carcinoma) herein used. This evidence concerns the gene TARBP2 and thyroid gland undifferentiated (anaplastic) carcinoma.