This is particularly helpful to demonstrate clonality of hematopoiesis in triple negative MPN patients, and such testing is recommended by the WHO 2016 guidelines for ASXL1, EZH2, IDH1/2, SRSF2, TET2, and SF3B1 in the absence of the classical driver mutations [19]. The gene discussed is TET2; the disease is myeloproliferative neoplasm.