Which markers indicate T-ALL?

In T-cell acute lymphoblastic leukemia (T-ALL), the identification of specific surface markers is crucial for diagnosis. The correct answer references the expression of markers that are characteristic of T-lymphocytes, typically indicating an early T-cell lineage. T-ALL cells often express markers such as CD2, CD5, CD7, and a range of T-cell receptor (TCR) components, but the lack of certain differentiation markers like CD10 is also significant.

The presence of CD2 to CD8 indicates that the leukemic cells have differentiated along the T-cell pathway, while the absence of CD10 helps to define the atypical nature of the malignant cells, distinguishing them from precursor B-cell leukemias, which typically express CD10.

Choosing markers like CD3 and CD4, or CD10, CD20, and CD22, would indicate either other types of leukemias or other subtypes of lymphoma that are not specific to T-ALL. CD19 and CD34 are generally associated with B-cell lineage, emphasizing that these markers would not align with a diagnosis of T-ALL, where T-cell specific markers dominate. Thus, identifying the expression of CD2 to CD8 without CD10 is indicative of T-ALL