RAPID DETECTION OF GAMMA-T CELL-RECEPTOR GENE REARRANGEMENTS IN ACUTELYMPHOBLASTIC-LEUKEMIA BY ELECTROPHORESIS AND SILVER STAINING - IMPLICATIONS FOR DETECTION OF MINIMAL RESIDUAL DISEASE

Minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL) w as studied using polymerase chain reaction (PCR). gamma T cell recepto r (TCRG) genes are ideal targets for PCR-based detection of MRD due to their molecular characteristics. Polyacrylamide gel electrophoresis ( PAGE) analysis of PCR products followed by silver staining was perform ed for 72 children with ALL at the onset of disease. Silver staining i s an effective technique to detect gene rearrangements without the use of ethidium bromide. Moreover, this method may show heteroduplex band s of a clonal nature when both TCRG alleles are rearranged. PCR produc ts subjected to a rapid staining protocol were recovered from the gel, reamplified by a second PCR and directly sequenced. After sequencing, we identified the junctional region and obtained patient-specific pro bes. In more than half of the patients we detected TCRG rearrangements that were used as molecular markers for residual disease.