Embryonic development protein active in cancer growth

A team of scientists at the University of California, San Diego Moores Cancer Center has identified a novel protein expressed by breast cancer cells – but not normal adult tissues – that could provide a new target for future anti-cancer drugs and treatments.

Led by Thomas J. Kipps, MD, PhD, Evelyn and Edwin Tasch chair in cancer research and interim director of the UC San Diego Moores Cancer Center, the scientists found that the tumour cells of patients with breast cancer frequently express the Receptor-tyrosine-kinase-like Orphan Receptor 1, or ROR1.  They found that silencing expression of ROR1 impaired the growth and survival of human breast cancer cells. The findings are published in the 5 March online issue of PLoS One.

ROR1 was first identified in the early 1990s and labelled an orphan receptor because its purpose was unknown. Subsequent work found that ROR1 is expressed at high levels during embryogenesis, during which time it plays an important role in regulating embryonic muscle and skeletal development.

During foetal development, however, the expression of this protein is turned off.  Normal cells and tissues in adults do not typically express ROR1.

Cancer cells, however, are a different matter.

''Cancer cells tend to acquire features of less differentiated cells,'' said Kipps, interim director of the UC San Diego Moores Cancer Center and a professor of medicine in the UC San Diego School of Medicine. ''They often can be found to have features of embryonic cells.''