Cancer generally has three types of therapy: radiation, surgery, and chemotherapy.  Burn it, cut it, or poison it.  Chemotherapy has been used to treat cancer since the 1940s.  Most chemotherapy drugs attack cells in specific stages of the cell cycle and cause them to undergo apoptosis ("poisoning the cells").  Since chemotherapy drugs do not specifically target cancer cells, they can incorporate into healthy cells and cause cellular death.  For this reason, many side effects are commonly associated with chemotherapy treatments.  Among these are blood clots, hair loss, diarrhea, angina, heart failure, sterility, nephrotoxicity, and urinary tract infections.

Recent advances have shown promise in selectively destroying tumor cells by targeting a therapeutic drug by conjugating it with a homing peptide.  Recent work has found many markers that are specific to particular tumors and/or to the tumor vasculature.  Through these markers, it is possible to kill tumor cells directly or by cutting off their blood supply.  To do so, we must find molecules that are specifically targeted to these markers.  These homing peptides, as they are referred to, are discovered through the screening of bacterial phages, which is documented on the phage selection process page.  The process of finding a suitable homing peptide, however, is a long and arduous process, and since many tumors are inherently different from one another, the process becomes more complicated.  The field of tumor targeting will greatly evolve when more and more common tumorogenic markers are found and homing peptides to those markers are identified.

The next step in this process is to develop suitable drug delivery devices that maximize the efficacy of the homing peptide/drug conjugates.  Nanoparticle delivery devices coated with homing peptides and a therapeutic drug have shown promise in localizing within a specific tissue in animal models.  The adhesion of the conjugate to a carrier device has the added benefit of sequestering the drug for a sustained release.  This is a promising feature in reducing the number of treatments needed.

Much of this research is being conducted through grants offered by the National Cancer Institute.  In October 2005 the NCI has provided grants to eight research centers, each worth $20 million over the next five years.  With some of the greatest drug delivery minds heading the research at these centers, there is a strong possibility that a breakthrough therapy can be developed within the next few years.  Details of the current research at these facilities is documented on the NCI-funded centers page.