Fig. 1: Examples of variable TdT expression in B-ALL.
From: Clinicopathologic and prognostic features of TdT-negative pediatric B-lymphoblastic leukemia
Flow cytometry scatter plots depict three separate cases of B-ALL with different levels of TdT expression. Expression of TdT was measured using T-lymphocytes as a negative internal control and cases were classified as TdT-positive if >10% of B-lymphoblasts expressed TdT at an intensity greater than that of the T-lymphocytes. Blue events represent T-lymphocytes and red events represent leukemic B-lymphoblasts. A Example of B-ALL classified as TdT-negative based on <10% of B-lymphoblasts expressing TdT at an intensity greater than that of the T-lymphocytes. B Example of a case classified as TdT subset positive due to dim TdT expression in >10% of B-lymphoblasts. C Example of TdT-positive B-ALL with uniformly bright TdT expression.
