In addition, ALDH1A3 expression has been correlated with poor prognosis in breast cancer [19], chemoresistance of mesothelioma [20] and radioresistance of head and neck cancer [21], and its inhibition has been proven to induce the cytotoxicity of those cancer cells that present an ALDH1A3 overexpression [19,22]. This evidence concerns the gene ALDH1A3 and head and neck cancer.