Identification of mRNAs differentially-expressed between benign and malignant breast tumour cells.
Two suppression subtracted cDNA libraries have been constructed, one containing cDNAs to mRNAs present at a higher level in a benign human breast tumour-derived cell line relative to the malignant mammary cell line, MCF-7, and the other containing cDNAs present at a higher level in the MCF-7 cells relative to the benign cells. Randomly-picked cloned DNAs have been sequenced yielding 29 and 128 different cDNAs from the benign and malignant libraries, respectively. Using reverse Northern hybridisation, 76% and 83% of the cDNAs were differentially expressed by greater than two-fold, whilst 14% and 11% of cDNAs in the respective libraries were differentially expressed by more than 15-fold. Amongst these were oestrogen-responsive cDNAs and expressed sequence tags. One such oestrogen-responsive expressed sequence tag, M41, is transcribed from a gene located on chromosome 21q22.3, within an intron of a larger gene. The M41 gene contains oestrogen response elements, one of which is associated with alu repeats. M41 mRNA is expressed at a statistically significantly higher level in human breast cancer specimens than in normal human breast and benign lesions. In carcinomas, its up-regulation is associated with the development of the malignant cell.
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School of Biological Sciences, Life Sciences Building, University of Liverpool, PO Box 147, Liverpool L69 7ZB, UK.
Rudland
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Sibson
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Barraclough
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D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism*; D002891:Chromosomes, Human, Pair 21; D020224:Expressed Sequence Tags; D015870:Gene Expression; D015723:Gene Library; D006801:Humans; D017403:In Situ Hybridization; D012333:RNA, Messenger / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger