Cloning of mRNA sequences from the human colon: preliminary characterisation of defined mRNAs in normal and neoplastic tissues.

RNA has been extracted from the normal human colon, converted into cDNA and cloned in the bacterial plasmid pBR322. About 4,000 sequences from this library were screened with probes derived from normal mucosa, familial polyposis mucosa, colonic adenocarcinomas and the colon tumour cell line HT29. Some mucosal sequences showed greatly reduced levels of transcription in neoplastic conditions, while a few showed elevated transcription. These have been further characterised by Northern and RNA dot-blot analysis.