How does RT-PCR work?
RT-PCR uses the same steps as PCR to amplify a segment of DNA, but the sample is a complimentary copy of mRNA. By starting with mRNA, this test measures only the DNA that is expressed, making it possible to determine the degree to which certain genes are expressed. Recent uses of RT-PCR in clinical oncology include detection of lymph node micrometastases in prostate cancer and bone metastases in breast cancer.[5] RT-PCR in breast cancer: The breast cancer test Oncotype DX™ utilizes RT-PCR to determine the individual risk of recurrence in women with node-negative estrogen receptor (ER)-positive breast cancer. This test evaluates expression of 21 genes in breast cancer. Overexpression of some of these genes indicates a worse prognosis, while expression of others may indicate a better prognosis. The expression of all 21 genes is used to calculate a “Recurrence Score™”, or the likelihood that that cancer will recur. A large clinical trial showed that Recurrence Score™ was more effective fo
