Heiden et al. (126) reported that activation of the Shh pathway leads to increased Snail expression in thyroid cancer cell lines, and that suppression of Snail expression by siRNA decreases the number of ALDHHigh thyroid CSCs in SW1736 and KAT-18 cells, two anaplastic thyroid cancer cell lines. This evidence concerns the gene SHH and thyroid gland undifferentiated (anaplastic) carcinoma.