PTEN and neoplasm: Overall, MSI-H tumors showed a significantly higher incidence of indel mutations involving homopolymer regions (0.45 vs. 0.19 per tumor), especially in the PTEN gene (0.28 vs. 0 per tumor, P < 0.001), but not in the APC gene (0.17 vs. 0.16 per tumor) (Table 5).