Evidence from the laboratory suggests that resistance to hormone therapy might occur when the oestrogen receptor is modified by enzymes called kinases. The team identified LMTK3 as a potential treatment target by screening for kinases that affect how cancer cells respond to oestrogen.

The researchers also compared DNA sequences in the gene coding for LMTK3 in humans and chimpanzees, because chimpanzees are not susceptible to oestrogen receptor positive breast cancer. They found that substantial differences have evolved in these sequences between the two species.

"It's quite intriguing that humans and chimps have evolved these differences in the LMTK3 gene, since related genes are very similar between the two species," said Dr Georgios Giamas, who designed and led the study, from the Department of Surgery and Cancer at Imperial College London.

"We could speculate that evolutionary changes in this gene might have given humans some unknown advantage, but also have made us more susceptible to breast cancer."

The research was funded by donations from private individuals and a grant from the US National Institutes of Health. Two of the authors are supported the Imperial College Cancer Medicine Centre (ECMC), funded by Cancer Research UK and the Department of Health.

www.imperial.ac