Exosomes--tiny, virus-sized particles released by cancer cells (and by virtually all cells in the body)-- can bioengineer micro-RNA (miRNA) molecules resulting in tumor growth. They do so with the help of proteins, such as one named Dicer. New research from The University of Texas MD Anderson Cancer Center suggests that Dicer may also serve as a biomarker for breast cancer and possibly open up new avenues for diagnosis and treatment. Results from the investigation were published online on October 23, 2014 in Cancer Cell. "Exosomes derived from cells and blood serum of patients with breast cancer, have been shown to initiate tumor growth in non-tumor-forming cells when Dicer and other proteins associated with the development of miRNAs are present," said Raghu Kalluri, M.D., Ph.D., chair of the department of cancer biology at MD Anderson. "These findings offer opportunities for the development of exosomes-based biomarkers and shed insight into the mechanisms of how cancer spreads." Exosomes are small vesicles consisting of DNA, RNA, and proteins enclosed in membranes made up of two lipid layers. They perform specialized functions such as coagulation, intercellular signaling, and cell "waste management." They are shed into bodily fluids forming a source of disease-specific nucleic acids and proteins. Increasingly, exosomes are studied for their potential as both indicators of disease, and as a prospective new treatment approach. Exosomes typically contain a cellular stew of smaller components including proteins, messenger RNA (mRNA), and miRNAs. Dr. Kalluri's team reported that breast-cancer-associated exosomes contain specific miRNAs associated with a multi-protein complex known as RNA-induced silencing complex (RISC).Login Or Register To Read Full Story