PLK4 and neoplasm: Disease-free survival (DFS) was not different between patients with tumor PLK4 IHC scores > 0 and ≤ 0 (P = 0.154) but was reduced in patients with scores > 3 vs. ≤ 3 (P = 0.009) and > 6 vs. ≤ 6 (P < 0.001).