CD7 and leukemia: However, depending on the considered leukemia sample and contrary to CD7+/CD34+ cells found in normal thymocyte differentiation, we observed that T-ALL-derived CD7+/CD34+ cells are not uniformly early T cell progenitors as they may co-express CD34 with mature surface markers such as CD4, CD8 and/or CD3/TCRαβ [9].