ALL Multiplex PCR 28 Translocations (MedGenome)

Function

This is a highly specialized molecular diagnostic test using Multiplex Polymerase Chain Reaction (PCR) to screen for 28 of the most common chromosomal translocations associated with Acute Lymphoblastic Leukemia (ALL). Translocations occur when parts of two different chromosomes break and swap places, creating 'fusion genes' (like BCR-ABL1) that drive the uncontrolled growth of leukemic blasts.

Why it is Ordered

In cases of suspected or confirmed ALL, this test is essential for risk stratification. Identifying the specific genetic driver allows oncologists to determine the aggressiveness of the leukemia, the likelihood of relapse, and the appropriate treatment intensity. It is also used to identify patients eligible for targeted 'smart' drugs (e.g., Tyrosine Kinase Inhibitors for Philadelphia-positive ALL).

Associated Conditions

• B-Cell Acute Lymphoblastic Leukemia (B-ALL): Various translocations like t(12;21) or t(9;22).
• T-Cell Acute Lymphoblastic Leukemia (T-ALL): Specific rearrangements involving T-cell receptor loci.
• Minimal Residual Disease (MRD): This test can sometimes provide baseline markers for monitoring treatment success.

Clinical Importance

The genetic makeup of ALL is the single most important prognostic factor. For instance, the ETV6-RUNX1 translocation generally carries a favorable prognosis, while the MLL (KMT2A) rearrangement indicates a high-risk profile requiring more intensive therapy or bone marrow transplant. This 'Multiplex' approach is efficient, as it tests for 28 variations simultaneously, saving critical time in the acute setting.