In situ polymerase chain reaction (PCR) is a very powerful tool, which enhances our ability to detect minute quantities of a rare, single copy number, target nucleic acid sequences in freshly frozen or paraffin-embedded intact cells or tissue sections (1 –10 ). In 1986, the introduction of PCR methods opened new horizons and revolutionized research in all areas of molecular biology (11 ,12 ). Dr. Hasse and his coworkers in 1990 used multiple primers and successfully amplified the target nucleic acid sequences in intact cells by combining a traditional in situ hybridization protocol with a powerful PCR technology (13 ).