Real-time quantitative reverse transcriptase polymerase chain reaction.

The real-time quantitative reverse transcriptase polymerase chain reaction (RQ-PCR) has become the method of choice for the quantification of specific mRNAs. This method is fast, extremely sensitive, and accurate, requires only very small amounts of input RNA, and is relatively simple to perform. These characteristics have made it the method of choice for minimal residual disease monitoring such as in chronic myelogenous leukemia (CML). CML comprises approximately 20% of all leukemias and is characterized by a balanced (9;22) chromosomal translocation that results in the formation of a chimeric gene comprised of the BCR (breakpoint cluster region) gene and the ABL oncogene (BCR-ABL fusion gene). The chimeric gene encodes a fusion protein with constitutively increased tyrosine kinase activity, resulting in growth factor-independent proliferation. This kinase is the target for current CML therapy, and BCR-ABL fusion gene levels are monitored to determine the effectiveness of this therapy. This chapter uses BCR-ABL transcript detection to illustrate an example for the RQ-PCR and describes a RQ-PCR method to detect the most common form of the BCR-ABL fusion transcript in CML, known as p210 BCR-ABL.