TBX15 and thyroid cancer: In the present study we show that demethylation with 5-aza-dC resulted in an increase of the TBX15 mRNA expression in TPC-1 thyroid cancer cells; however, no correlation was found between methylation levels in the CpG island of TBX15 analyzed and the TBX15 mRNA expression, in nine thyroid cancer cell lines and HeLa cells.