LDHA and thyroid cancer: By contrast, Shimamura et al. (115) showed that inhibition of ALDH activity with a specific inhibitor or by siRNA knockdown reduces ALDH-positive cells but does not significantly lower the number and growth of thyrospheres of four thyroid cancer cell lines (FRO, ACT1, KTC3, and 8505C), suggesting that ALDH may be just a marker for thyroid CSCs and may not have a functional role in thyroid CSC self-renewal.