Detection of messenger RNA in routinely processed tissue sections with biotinylated oligonucleotide probes

In situ hybridization (ISH) with a radioactively 35S-labeled probe and a biotinylated oligonucleotide probe for human calcitonin was used to analyze eight cases of medullary thyroid carcinoma (MTC) in paraffin sections. Three of these cases were also studied with frozen tissue sections. The biotinylated probe readily detected calcitonin messenger RNA (mRNA) in routinely processed formalin-fixed paraffin-embedded tissue section within 24 hours. Northern hybridization and other control studies demonstrated the specificity of the calcitonin probe. Biotinylated oligonucleotide probes for other mRNAs present in high abundance such as adrenocorticotroipic hormone (ACTH), prolactin, and growth hormone also detected the respective mRNAs in pituitary tissues. These result show that biotinylated oligonucleotide cDNA probes can be used to detect specific mRNAs present in large amounts in some endocrine cells and tumors by ISH. This approach offers an alternative that does not require the use of molecular cloning or radioactive probes for this investigative and diagnostic technique.