Which enzyme is a known marker for acute lymphocytic leukemia?

The identification of terminal deoxynucleotidyl transferase (TdT) as a known marker for acute lymphocytic leukemia (ALL) is grounded in its role in the development and differentiation of lymphoid cells. TdT is an enzyme involved in DNA synthesis, specifically in adding nucleotides to the 3' ends of a DNA molecule, which is crucial during the maturation of lymphocytes.

In the context of ALL, the presence of TdT is typically used in immunophenotyping to help confirm the diagnosis. It is particularly associated with precursor lymphoblastic cells. Elevated levels of TdT can indicate an immature state of lymphoid cells, which is characteristic of leukemias primarily affecting lymphoid lineages.

The other options, while they may serve specific functions in clinical biochemistry or other types of leukemia, do not specifically correlate with acute lymphocytic leukemia in the same manner as TdT. Alkaline phosphatase, for example, is associated with liver function and bone metabolism, lactate dehydrogenase is commonly elevated in tissue damage or certain malignancies, and amylase is primarily related to pancreatic function. However, none of these enzymes serves as a reliable marker particularly for ALL, making TdT