CD7 and T-cell and NK-cell neoplasm: However, in T-lymphoblastic leukemia/lymphoma, the neoplastic cells typically express one or more markers of immaturity, such as TdT or CD34, and typically exhibit strong staining for CD7, in contrast to the absence of TdT and CD34 expression and decreased or absent CD7 expression observed in many mature T cell neoplasms [3,20,21,22,33].