The Physics of Living Systems Community has collectively become excited at the possibility of contributing to a better understanding of cancer. The signs of this are manifold. There is a workshop scheduled next spring at the KITP in Santa Barbara on the Physics and Mathematics of Cancer, co-organized by physicists and by cancer biologists. There is a tutorial on Sunday at the upcoming American Physical Society March meeting in Boston to introduce this subject to interested attendees. There is a special issue of the journal Physical Biology (Vol 8.,No. 1 in 2011) devoted to research at the National Cancer Institute sponsored Physical Science Oncology Centers. And, we here at the Center for Theoretical Biological Physics will be starting a new synergy research area devoted to this topic.

So, what gives? I think the answer here lies in the fact that physical science can offer both tools and concepts that could help deal with the amazing complex story of cancer as it has become to be understood. Aside from some special cases, attempting to cure cancer by following the simple path of finding a single defect (perhaps one key mutation leading to constitutive activity of a signaling protein) and then devising a small molecule therapy just has not proven to be a powerful enough strategy. In fact, cancers often respond to such treatment with short-term retraction followed inexorably by long-term renewed vigor. This defeat of therapy can occur by a variety of individual cell changes (resistance mutations for example), by collective changes within the entire tumor, by recruitment of surrounding normal cells; the details are sorely absent. Surely coupled to this is the fact that cancers are remarkably heterogeneous in their genomic profiles and in their physical manifestations; there are many redundant pathways leading to similar dire consequences. We as a society are thus faced with the prospect of pending hundreds of thousands of dollars per patient on drugs that increase life expectancy by merely a few months. It may be the height of hubris to think that physicists can make progress on topics that have resisted the best efforts of the oncology community, but there is certainly a strong motivation to try.

And, there are good intellectual reasons as well to work on cancer. Cancer touches on some of the most basic questions underlying biology, related to the plasticity of genetic degrees of freedom, the nature of cell differentiation, the constraints that multi-cellularity places on the proliferation and selfish behavior of individual cells, the role of environment in both genotypic selection and phenotypic behavior etc. There is room here for working on evolutionary dynamics, on genetic systems that control cell fate, on the mechanics of cell motility, on high-resolution imaging inside the human body, and on the design of drug delivery systems. So, as you ponder where you can make your own personal contributions to the Physics of Living Systems, do not overlook the possibility of working on the physics of cancer; it is one of the true challenges of our time.

Prof Herbert Levine, Rice University