DETECTION OF EPIDERMAL GROWTH-FACTOR RECEPTOR MESSENGER-RNA IN TISSUE-SECTIONS FROM BIOPSY SPECIMENS USING IN-SITU POLYMERASE CHAIN-REACTION

Human epidermal growth factor (EGF) receptor mRNA was detected in cryo preserved tissue sections adherent to whole glass slides using in situ reverse transcriptase polymerase chain reaction. EGF receptor cDNA wa s synthesized in situ by reverse transcription using an EGF receptor s pecific oligonucleotide primer. In situ polymerase chain reaction ampl ification in the presence of digoxigenin-11-dUTP and subsequent bindin g with an antidigoxigenin antibody conjugated to alkaline phosphatase allowed direct visualization. Because DNase, RNase, or proteinase K ar e not required, tissue integrity is maintained. EGF receptor mRNA is e xpressed in the basal layer of normal human shin epithelium and is sig nificantly overexpressed in squamous cell tumor specimens, which is co nsistent with conventional analysis of EGF receptor expression. The as say is semiquantitative, quicker, more sensitive, and void of the nons pecific binding associated with in situ hybridization In situ reverse transcriptase polymerase chain reaction using whole glass slides is id eally suited for detecting moderate to infrequently expressed transcri pts in biopsy specimens.