Breast cancer research on chip

Recently, significant advances in the prevention, diagnosis and management of breast cancer have been made. Nevertheless, worldwide, every year, 460,000 women die of breast cancer (1). The conventional approach to cancer therapy is to provide treatment according to the organ or tissue in which the cancer originates. Currently, the selection of which breast cancer therapy is based on a broad scale of factors, including a patient's age and tumour characteristics, such as nodal stage, the presence of oestrogen receptors and the Her-2/neu status (2). However, the various protocols that exist for chemo- and hormone therapy have different and limited rates of success. Often, this approach to cancer treatment is referred to as 'trial and error' or 'one-size-fits-all' (3). This practice is inefficient and frequently results in inappropriate therapy and treatment-related toxicity. In contrast, personalised treatment has the potential to increase efficacy and decrease toxicity. Nowadays, it is known that cancer develops as a result of multiple genetic defects and that individuals with the same type of cancer often have dissimilar genetic defects in their tumours (4). This finding explains why patients who seem to have similar cancers respond in a heterogeneous manner to antitumour agents and show clearly the huge obstacle to providing effective treatments for cancer. The hypothesis that stem cells play an important role in tumour biology receives a lot of attention (5). These so-called cancer stem cells (CSC) have the ability for self-renewal and are pivotal in setting the heterogeneous character of a tumour. Besides influencing the origin and growth of tumours, these CSC play an important role in developing metastasis. For personalised medicine, individual treatment regimes have to be set to define the best treatment possible for every patient. Currently, personalised treatment is most advanced for breast cancer. To achieve personalised treatment for cancer, (bio)markers for determining prognosis, predicting response to therapy, and predicting severe toxicity related to treatment are needed (3). DNA/RNA-microarrays for breast cancer prognosis, but also prediction, are very promising and at present clinical validation is ongoing (6). Recently, the use of microtechnologies for cell biology applications, and specifically for cancer, has received rapidly growing attention (7). Lab-on-a-Chip technology is a promising platform for personalised oncology to predict response or resistance to therapy, so that the individual patient receives the right drug. Even though results from in vitro assays can't be directly and uniformly translated to the in vivo situation, the in vitro approach to determining drug sensitivity and resistance continues to have great potential to spare patients the morbidity of ineffective treatment. Here, the development of a microfluidic chip ('Apoptosis chip') to screen the effect of well-known antitumour drugs on human breast cancer cells is described. Moreover, preliminary results on cancer stem cells are shown.