Prof Leonie Young hosted a two-day Breast Cancer Meeting in Royal College of Surgeons. International experts, researchers, academics and clinicians came together to discuss the latest developments in the field of breast cancer research. The meeting, kindly supported by Breast Cancer Ireland, featured an excellent line-up of speakers that presented work on the very latest in clinical and translational research. Prof Steffi Oesterreich, University of Pittsburgh, presented a paper on Estrogen Receptor gene (ESR1) and its role in treatment resistance. Typically this gene can be found in 70% of breast cancer patients and is responsible for driving the growth of breast cancer cells. It is a good prognostic marker and it is readily targeted by the mainstay anti-hormonal therapies. Recent studies have revealed non-inherited mutations in the ESR1 gene could be responsible for treatment resistance that enables breast cancer to spread to other sites of the body. Prof Oesterreich’s lab used a novel technique to detect these mutations in the blood samples, small numbers of primary tumours and in breast cancer that has spread to organs such as brain and bone. This information could be used to help clinicians tailor treatments and identify patients who will be not benefit from continued treatment. Further research is required in improving the sensitivity of the technology used as well as identifying the small number of patients that would benefit from an alternative treatment strategy. Prof Adrian Lee presented an exciting new collaboration with the Breast Cancer Ireland Centre researchers Prof Leonie Young and Dr Damir Varešlija. His presentation focused on mapping the genetic changes that enable the primary breast cancer to spread to the brain. The study found striking alterations in key clinically important genes that were identified in a significant portion of patients with brain metastases. These changes appear to be specific to the brain relative to other metastatic sites. This research may well have immediate clinical implication as it suggests a change in therapeutic strategy for a subset of breast cancer patients.