TET2 and angioimmunoblastic T-cell lymphoma: Furthermore, TET2 mutations present in AITL have also been found in isolated CD34-positive cells, CD8-positive T cells, benign B cells, and tumor cells, supporting the notion of a mutated stem cell progenitor cell (Couronné et al. 2012; Schwartz et al. 2017; Cheng et al. 2021).