Detection of reverse transcriptase activity in human breast tumors.

The function of reverse transcriptase (RT) in retroviruses is to copy their RNA genomes in DNA to be integrated into the host genome. We report a high purity preparation of this enzyme by adsorption onto poly(U)-sepharose. We analyzed RT activity with poly(rA)--oligo (dT)12-18, poly(dA)--oligo (dT)12-18, poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18 to obtain a more accurate pattern of RT. 8 out of 16 malignant breast samples were positive for RT activity, more specifically with poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18. The 5 non-malignant mammary samples tested were negative for RT activity. Assays with poly(rC)--oligo (dG)12-18 and poly(rCm)--oligo (dG)12-18. The 5 non- malignant mammary samples tested were negative for RT activity. Assays with N--nitroso--N--methylurea--induced rat mammary carcinomas were negative for RT activity.