Quantifying residual leukemia by "clone-specific" polymerase chain reaction

Molecular biology tests can quantify extremely low levels of cancer cells, provided that a genetic marker for the cancer is known. Acute lymphoblastic leukemia (ALL) exhibits many genetic abnormalities, but most are uncommon or technically difficult to use as markers for sensitive quantification. We therefore use the leukemia clone's rearranged immunoglobulin heavy-chain (IgH) gene as a clonal marker (1,2). A very sensitive, quantitative polymerase chain reaction (PCR) test with "clone-specific" primers can be developed for 60-70% of B-lineage ALLs (see Fig. 1 ). Fig. 1. Strategy for quantifying residual disease.