POT1 and thyroid cancer: Two independent studies reported an association of GPVs in POT1 with familial melanoma.3 4 Further core ‘POT1 associated tumours’ including angiosarcoma (AS), haematological malignancy and brain tumours have been suggested.5, 7 A wide phenotypic spectrum of cancer types, including other sarcomas, colorectal and thyroid cancer, has been described within POT1-TPDS families.8 9