We describe a rapid and efficient RT-PCR method particularly suited to
procedures involving limited cell and target gene copy numbers. Purif
ied leukocytes and myeloid colonies derived from patients with chronic
myelogenous leukemia (CML) in chronic phase were used for direct RT-P
CR. Purified cells and colonies were lysed using a small quantity of D
EPC-treated water containing RNasin as an RNA inhibitor. The untreated
lysate was either used immediately for RT-PCR or frozen at -70 degree
s C for later use. By this method we were able to consistently amplify
bcr-abl transcripts from as few as 10 cells. No noticeable difference
was observed between products amplified from fresh and frozen samples
.