Welcome back to Ask a Biogeek, a column where you ask biology researcher Terry Johnson any question you want - no matter how weird. Reader Charlie writes:
How about an article on the current cutting edge cancer research/treatments? Is there anything out there that is promising? Will there be a cure in our lifetimes?
Sadly, cancer is not a single disease, but a class of diseases - while we may effectively cure some forms of cancer, it's doubtful that we'll be able to cure them all, and unlikely that a single form of treatment will be effective against all or even a wide range of cancers. The cells in our bodies are tightly regulated, but over time entropy has its way, and some lose their original genetic programming. Often these breakdowns are harmless and strictly local, but in the case of cancer, they can be catastrophic.If you look at the human body as an ecosystem, it's remarkably well-behaved. Various types of cells fulfill their proper roles in their proper places. The rapid cellular growth that is appropriate in the lining of our guts, for example, would be hazardous in the adult brain. Cells are regulated by their microenvironment (hormones, the surrounding tissue, etc.), with healthy cells reacting as you would expect. Cells with DNA damage resulting from viral infections, exposure to carcinogenic chemicals or radiation, or simple error during division are not so predictable. The body is not entirely unprepared for damaged cells. Our immune system seeks them out, and there are mechanisms within the cell designed to sense damage and cause apoptosis - programmed self-termination. These systems catch many dangerous cells, but not all.
If a damaged cell escapes the immune system and its own self-destruct devices, it will often grow more damaged with time, accumulating mutations. A "successful" cancer will acquire additional mutations that allow it to grow uncontrollably into a tumor, feed itself via the formation of blood vessels, and metastasize - break away from the original tumor to form new colonies elsewhere in the body. Not every cell in the tumor needs to be the same for this to happen; if even a small population of cells hits a combination of errors that allows it to break away and take root elsewhere, the prognosis can be bleak. I'm talking about cancer in a very general sense, but it's important to remember that not all cancers are the same. The types of cellular breakdown that lead to an aggressive breast cancer are not necessarily the same as the damage that would give you leukemia (though there may be a few gross similarities), and they originated with different kinds of cells in the first place, housed in different tissue niches. Nor are all cancers of the same general type the same - for example, some breast cancers overexpress a protein called HER2, but not all. So, a tumor is composed of a mixture of cells which share some (but not all) of the same kinds of breakage with their immediate neighbors, cancers of the same type in other patients, and cancers of a different type entirely. It's hard to come up with a generalized cure when there are so many different ways for cells to flip out. Early detection of a treatable cancer is critical. If you can catch the tumor before it metastasizes, you have only a single tumor to deal with. Imaging techniques like mammograms, X-rays, and MRIs can be used to detect tumors, though more exotic techniques for detection are on the way. Dogs have been shown to be capable of smelling cancer, and research into the compounds they detect could lead to an artificial diagnostic nose.
Cellular therapies are another option. If your immune system is full of fail, perhaps it's time to send in the cavalry? Immune cells from cancer-resistant mice can be used to kill advanced tumors in normal mice (well, "normal" for lab mice, anyway). Cells can also be used to target existing treatments to the site of the cancer, by using genetically modified cells that home in on a tumor and, once there, activate an anti-cancer drug, reducing the wear and tear of side-effects on your healthy tissue. Since viruses are already quite good at homing in on cells, they're another potential cancer-busting option. Nanotechnology has a few tricks up its sleeve if cells and viruses don't do the trick. Nanotubes can be loaded with drugs and "capped", potentially capable of releasing an anti-cancer payload on demand (though the "demand" part is still under construction). Once localized to a cancer cell, light at an appropriate wavelength zaps the nanotube, which absorbs it and heats up, effectively cooking the tumor.
Similar results have been achieved using gold-plated nanoparticles, while bundles of nanorods form light-activated cancer-shredding cluster bombs: "As if billions of cancer cells cried out...and were suddenly silenced."
It's likely that not all of these approaches will bear fruit - if every cancer cure that worked on rats also worked on humans, I probably wouldn't have to answer this question. With a disease as diverse as cancer, however, it makes sense to approach a wide variety of possible treatments. Do you have questions you've always wanted to ask a biogeek? You can email Terry Johnson.