A procedure that produces millions of copies of a short segment of DNA through repeated cycles of: (1) denaturation, (2) annealing, and (3) elongation. PCR is a very common procedure in molecular genetic testing and may be used to generate a sufficient quantity of DNA to perform a test (e.g., allele-specific amplification, trinucleotide repeat quantification). Also called polymerase chain reaction. or A mixture of eight herbs that has been sold as a dietary supplement and promoted as a way to keep the prostate healthy and to treat prostate cancer. PC-SPES has been studied in the treatment of prostate cancer, but has been taken off the market in the U.S. because of safety concerns.