DLK1 and neoplasm: Although no association was found between DLK1 copy number and age (p = 0.86), gender (p = 0.55), multifocality (p = 0.55), extrathyroidal extension (p = 0.68) and vascular invasion (p = 0.24), DLK1 copy number gain was associated with a larger tumor size (p = 0.04; Figure 6a).