Dr Wong: Looking at the advances in the treatment of breast cancer， the most important advance has been in understanding the molecular nature of breast cancer and that it is not a homogenous disease. We now understand that there are different subtypes of disease such as the HER2-positive disease and the endocrine receptor positive disease. What is left is a mixed bag; we call it triple-negative disease. But triple-negative is not defined in a positive way. It is defined by exclusion so is a bit of a mixed basket which is why advances in this particular area of triple-negative breast cancer appear to be fewer.

　　Of the three subgroups I have mentioned， it would be the HER2-positive and the estrogen receptor positive subgroups that have seen big advances because we have come to understand the mechanism behind tumor growth. For the HER2-positive breast cancers， we have new agents like pertuzumab to be used together with trastuzumab. Pertuzumab prevents the dimerization of HER2 receptors with other receptors in the HER family which produces better results in first-line treatment. Even for very resistant disease with T-DM1 where the thioether link is able to link a cytotoxic agent with the monoclonal antibody trastuzumab， allowing for a very targeted delivery of cytotoxic to the cell， leads to much improved treatment results. For example， with the PARP inhibitors， which were initially thought to be very effective for the triple-negative disease because we believed DNA repair was a weakness of these types of tumors， we have found that not to be the case because they are not homogenous. It is only as subset of triple-negative tumors that respond to that. So this triple-negative group of breast cancers will only see major advances when we understand how to sub-classify them in a positive sense rather than in a negative sense by exclusion.