It is now believed that luminal progenitor cells – the ‘daughters’ of breast stem cells – are the likely source of basal-like breast tumors that develop in women carrying mutations in the gene BRCA1. This discovery was made by a team led by Associate Professors Jane Visvader and Geoff Lindeman (couple of other authors' publications: 1,2,3,4; reviews: 1,2)  of the Walter and Eliza Hall Institute’s Victorian Breast Cancer Research Consortium Laboratory, and was published in today’s issue of the journal Nature Medicine. Dr. Visvader indicated that in recent years it has been believed that the breast stem cells are what give rise to BRCA1 tumors. Yet breast tissue from women with BRCA1 mutations has been found to have an unexpectedly high number of luminal progenitor cells, as seen in the research conducted by Dr. Elgene Lim and Dr. François Vaillant at the institute. After the gene expression studies revealed BRCA1 breast tissue and basal breast tumors to be more similar to normal luminal progenitor cells than any other cell type in the breast, focus has shifted away from breast stem cells to errant luminal progenitors.

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Researchers at the University of Rouen, France, have discovered a new strain of HIV in a 62-year-old woman from Cameroon now residing in Paris. Prior to this discovery, three HIV strains were known , all related to the simian virus carried by chimpanzees. This new strain differs from the previous three in that it appears similar to a strain of simian virus found in gorillas. While most likely transmitted directly from gorillas to humans, researchers say it is also possible that it began in chimpanzees, moved into gorillas and then to humans, or perhaps moved directly from chimpanzees to both gorillas and humans. The woman has said that she had no contact with apes or bush meat, which could mean that she became infected with the virus through human contact. The rapid replication of the virus, moreover, indicates that it is adapted to human cells. The prevalence of the strain is yet undetermined, and it could be circulating in western central Africa, according to researchers.

(Source: Randolph E. Schmid (AP), “New HIV strain discovered in woman from Cameroon,”)