POSSIBLE RETROVIRAL ETIOLOGY OF HUMAN BREAST-CANCER

Since the discovery in the early 1980s that retroviruses are pathogeni c to man, the mouse mammary tumor viruses (MMTVs) received great atten tion. Studies of MMTVs allowed considerable insights into the mechanis ms at work in breast tumorigenesis. MMTVs are essentially insertional mutagenes. Numerous oncogenes have been found altered by MMTVs, either specific for MMTVs or not. However, despite considerable attempts, th e involvement of MMTVs in human breast cancer remains questionable. Ye t a retroviral etiology of human breast cancer cannot be discarded sin ce retroviruses are good candidates to play a role in diseases which, like human breast cancer, appear either as sporadic or inherited. Due to their replication cycle, retroviruses can be propagated not only as infectious agents able to freely infect host cells, but also as cellu lar genes which can be passed on to progeny. It is suggested here to s earch for a new human retrovirus in sporadic bl east cancer, using the techniques which led to the isolation of human T-cell leukemia virus- 1 (HTLV-1). Indeed, finding an infectious retrovirus in sporadic cases could lead, via the c-DNA probes derived from it, to testing the hypo thesis that the inherited form of human breast cancer may result from the action of retroviral genes integrated in the germ line. (C) 1998 E lsevier, Paris.