Over-expression of XIAP was found to be associated with older age at diagnosis (p < 0.0001), tall cell variant of PTC (p < 0.0001), extrathyroidal extension (p < 0.0001), larger tumor size (p = 0.0007), lymph node metastasis (p = 0.0023) and advanced stage (p < 0.0001) (Table 3). This evidence concerns the gene XIAP and metastasis.