PMS2 and Merkel cell skin cancer: Given the co-occurrence of mutations found in DACH1 with MLH1, POLE, and PMS2, we then compared microsatellite instability between DACH1 mutated patients and DACH1 wild-type in the MCC cohort using the chi-square test, and no significance was found between the two groups (p-value = 0.2659) as shown in Table 8, with 3/12 DACH1 mutated patients being MSI-H, and 8/12 being MSS, and one patient with MSI unavailable.