What is a key marker that differentiates B-ALL from T-ALL?

To distinguish between B-cell acute lymphoblastic leukemia (B-ALL) and T-cell acute lymphoblastic leukemia (T-ALL), CD10 is an essential marker. CD10, also known as common acute lymphoblastic leukemia antigen (CALLA), is typically expressed on B-precursor cells. Its presence is particularly indicative of B-ALL, especially in the pediatric population where this disease is more prevalent.

In contrast, T-ALL is characterized by the expression of markers such as CD5 and CD7, which are associated with T-cell lineage. CD19 is a pan-B-cell marker found in both B-ALL and T-ALL, thus it cannot effectively differentiate between the two. CD25, while relevant in certain contexts like the activation of T cells, is not a definitive marker for distinguishing between B-ALL and T-ALL.

Thus, the expression of CD10 is a critical marker to identify B-ALL, highlighting its role in differentiating this subtype from T-ALL.