Breast cancer is the field of medicine with the greatest presence of nanotechnological therapeutic agents in the clinic. A pegylated form of liposomally encapsulated
doxorubicin is routinely used for treatment against metastatic
cancer, and
albumin nanoparticulate chaperones of
paclitaxel were approved for locally recurrent and metastatic disease in 2005. These drugs have yielded substantial clinical benefit, and are steadily gathering greater beneficial impact. Clinical trials currently employing these drugs in combination with chemo and
biological therapeutics exceed 150 worldwide. Despite these advancements,
breast cancer morbidity and mortality is unacceptably high. Nanotechnology offers potential solutions to the historical challenge that has rendered
breast cancer so difficult to contain and eradicate: the extreme biological diversity of the disease presentation in the patient population and in the evolutionary changes of any individual disease, the multiple pathways that drive
disease progression, the onset of 'resistance' to established therapeutic cocktails, and the gravity of the side effects to treatment, which result from generally very poor distribution of the injected therapeutic agents in the body. A fundamental requirement for success in the development of new therapeutic strategies is that
breast cancer specialists-in the clinic, the
pharmaceutical and the basic
biological laboratory-and nanotechnologists-engineers, physicists, chemists and mathematicians-optimize their ability to work in close collaboration. This further requires a mutual openness across cultural and language barriers, academic reward systems, and many other 'environmental' divides. This paper is respectfully submitted to the community to help foster the mutual interactions of the
breast cancer world with micro- and nano-technology, and in particular to encourage the latter community to direct ever increasing attention to
breast cancer, where an extraordinary beneficial impact may result. The paper initiates with an introductory overview of
breast cancer, its current treatment modalities, and the current role of nanotechnology in the clinic. Our perspectives are then presented on what the greatest opportunities for nanotechnology are; this follows from an analysis of the role of
biological barriers that adversely determine the
biological distribution of intravascularly injected therapeutic agents. Different generations of nanotechnology tools for
drug delivery are reviewed, and our current strategy for addressing the sequential bio-barriers is also presented, and is accompanied by an encouragement to the community to develop even more effective ones.