Homology between human breast tumour RNA and mouse mammary tumour virus genome.

Abstract

SEVERAL studies have provided indirect evidence linking particles related to mouse mammary tumour virus (MuMTV) with human breast cancer1–3. In addition to morphological and biochemical similarities between human milk particles and known oncornaviruses shown in several laboratories4, Axel et al.5 demonstrated partial homology between MuMTV genome and polysomal RNA isolated from human breast tumour by molecular hybridisation experiments. Using Cs2SO4 density gradient analysis they showed that 67% out of 29 tumours tested had detectable amounts of MuMTV-related RNA. But because of intrinsic problems involved in Cs2SO4 gradient analysis it is not possible to determine hybridisation quantitatively. In this paper we describe hybridisation experiments using MuMTV-specific DNA probes and human tumour RNA under stringent conditions.