Between nucleotides (nt) -1946 and -1938 and between nt -1942 and -1933 on the PDS (SLC26A4) gene promoter exist putative binding sites of TTF1 and TTF2 respectively which are essential for the activity of the PDS promoter, as demonstrated by mutation analysis in human thyroid follicular carcinoma (LA2) cells (172). The gene discussed is SLC26A4; the disease is thyroid gland follicular carcinoma.