If there is even a single simplicity lurking within cancer, a single commonality of biochemistry, a single dominant class of mechanism that passes through a bottleneck of complexity, then cancer will soon be a thing of the past. The technologies and research communities of this present biotechnology revolution will run it over and squash it flat. The common thread will be found, and therapies cranked out in short order to disrupt or suppress its operation.
So we can hope that varieties of the "cancer's evolutionary tendencies guarantee its unlimited variance and unremitting complexity" argument turn out to be false in the end. It's a reasonable thing to hope for, given the way in which evolved systems tend to be constructed. Take this research reported in EurekAlert!, for example:
researchers have devised a way to generate large numbers of human breast cancer stem cells in mice and have discovered a genetic switch that regulates critical properties of the cells. The regulator, which belongs to a class of molecules called microRNAs, pushes the stem cells to become more differentiated and less tumorigenic through its ability to switch off particular genes.
With a ready supply of cancer stem cells, the researchers were able to measure levels of microRNAs, small gene regulators that are known to influence a gene’s ability to create proteins important for cell growth and differentiation. They found that cancer stem cells contained low amounts of several microRNAs compared to more mature tumor cells or stem cells that had differentiated in culture.
They zeroed in on a tumor-supressing microRNA called let-7. When the team activated let-7 in the stem cells, they lost their ability to self-renew and began to differentiate. The cells also became less able to form tumors in mice or to metastasize. Further studies showed that let-7 did this by switching off two cancer-related genes: the oncogene Ras, and HMG2A, which when switched off caused the cells to differentiate.
If this finding applies to other tumor types, let-7 may offer a unique opportunity to attack tumor stem cells using therapeutic RNA. Delivery of the let-7 RNA to tumors could potentially deplete stem cells by pushing them down the path of differentiation.
This is one of a hundred different investigations into the biomechanisms of cancer that might - maybe - expand out to something that could be called a cure for cancer. If there is key, or class of keys to the creation of cancer - a point at which a spanner can be thrown into the works with the biotechnologies of the 2000s and 2010s - I'll wager it will be found and exploited sometime within the next decade.