Good news on the cancer front

How genetics is being used to find and beat cancer
Some of the biggest genetics news in the last couple of weeks dealt with cancer. But wait a minute, you might be saying, isn't this story supposed to be about genetics news? Yes it is but cancer is fair game because genetics and cancer go hand in hand (click here to learn more). Cancer starts out as a cell, just sitting there, minding its own business. Suddenly, something happens to the cell's DNA. Maybe the sun has caused a mutation in a gene in a skin cell. Or, the cell has just divided and it made a mistake when it copied its DNA. Or something in cigarette smoke has mutated the DNA of a lung cell. Whatever caused the DNA change, this mutation in the gene has unleashed the cell's ability to grow and divide*. A cell is usually under tight control and is only allowed to grow and divide a certain amount in certain places. Now, because of the DNA mutation, it is free to grow, make copies of itself and even spread out a bit. This is the definition of cancer. How does changing a gene make a cell dangerous? These mutations can make a cell start growing uncontrollably in lots of different ways, depending on the gene that is affected. Some genes are on only when we're growing. For example, when we are an embryo, all sorts of growing is going on. The liver goes from a single cell to millions and millions of cells. And genes are telling the liver cells to grow and divide. Now, you wouldn't want that to keep going. Once your liver is about the right size, you want to shut off those genes and keep on only the ones that let a liver be a liver. What would happen if something we ate mutated the DNA around one of these genes in a liver cell? The gene for growing a liver might turn back on. And so that cell would start growing again possibly becoming liver cancer one day. Some genes are on and telling other genes to stay off. These are in cells that don't need to grow right now but might in the future (think of the breast cells responsible for making milk). If the DNA around one of these gets hit and this gene gets shut off, then the cell is free to grow. The cell might turn into a cancer. Two very exciting areas of cancer medicine right now are making medicines that target these genes and using these genes to find cancers early. The next two sections will deal with each of these. *Not all mutations are bad…most have no effect and a very few are good (click here to learn about a useful mutation).
Herceptin just keeps getting better and better
Most cancer treatments are pretty general—they kill any growing cell in the body. More effective treatments might come if doctors had medicines that could target only cancer cells. While this day isn't here yet, the search has resulted in some very effective medicines. One of these is Herceptin. Herceptin targets cells that have the her2 gene turned on. For the most part, this means Herceptin only goes after certain cancers and leaves "normal" cells alone. One kind of cancer that Herceptin can effectively treat is the 15-25% of breast cancers that have the her2 gene turned on. These her2 positive breast cancers are some of the nastiest around. When her2 is on, breast cancer spreads very quickly and many common breast cancer drugs don't work well. The breast cancer also comes back more often after treatment. In the past, Herceptin was found to be very effective on patients with advanced breast cancer. The two studies reported in the New England Journal of Medicine looked to see how Herceptin worked in patients with early stage, her2 breast cancer. The results were astonishing. In these two studies, either 23% or 33% of women treated with only surgery and chemotherapy relapsed after four years. In other words, their cancer came back sometime within four years after treatment. When Herceptin was added to the mix, the number fell to 15% in both studies. The risk of breast cancer returning after surgery was reduced by half. Very few cancer treatments are that effective. Of course, the treatment only worked for women with breast cancers that had the her2 gene on. But since these are the toughest cancers to battle, this is a huge advance forward. And maybe scientists can find a "magic bullet" for some of the other 75-85% of breast cancers.

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Finding the cancer before it spreads
What would be more useful than a better medicine? Not having to use medicine at all. If you can find a cancer early enough, you may not need to use medicines like chemotherapy that have such harsh side effects. The best way to treat cancer is to find it early and remove it with surgery. Scientists are working on ways to find cancers when they are small and haven't yet spread. This is easier for some cancers than others. Some cancers we can see or feel when they appear. For example, skin cancer can be pretty obvious. And we can often find breast, testicular and prostate cancers by looking or feeling for lumps. Other cancers can be found with tests in the doctor's office. Some tests, like a mammogram or the PSA blood test are easy enough that patients are pretty willing to have them done. Other tests, though, are so intrusive that even though they are effective, many patients want nothing to do with them. The test for colon cancer is one of these. The tests that exist for finding colon cancer early are incredibly effective. And incredibly intrusive. The test, called a colonoscopy, involves snaking a camera into the patient to look at the inside of his or her colon. You can imagine the route the camera takes to get into the body. And you can imagine how thrilled most people are by this test. Many of the 56,000 people who die each year from colon cancer could have caught it early if they had had a colonoscopy. But they didn't because the test is so unpleasant. So scientists are trying to come up with a blood test for colon cancer instead. And this week they reported some encouraging progress on this front. In about 85% of colon cancers, a gene called APC has been turned on. Researchers found they could detect the turned on APC gene in the patients' blood. So will the blood test replace the colonoscopy? Probably not. It is important to note that the test didn't catch all colon cancers. Remember, 15% don't have the abnormal APC gene. And it won't catch the disease at its very earliest stage—premalignant growths. In other words, the colonoscopy is here to stay. But this new test would find many cases of colon cancer that are missed today, if the work holds up. So maybe more colon cancers can be caught early with a simpler test. But what about cancers for which there is no test at all? Cancers like ovarian and pancreatic cancer are so deadly because there often is no sign of a problem until the cancer has spread. Once a cancer spreads, it is much more difficult to treat. But there isn't an easy way to look at an ovary for example. There is no equivalent of a mammogram. So scientists are focusing on a blood test. The first step in creating a blood test is to find something in the blood that is only there if there is a cancer. Researchers have found that two genes, N33 and NFA6R, are turned off pretty early on in many ovarian cancers. The hope is that these two genes might be used as markers for ovarian cancer. Both the colon and ovarian cancer blood tests are at an early stage (with the colon cancer test being further along). Researchers don't even know if the genes found in the ovarian cancer can be easily seen in the blood. In other words, both of these need a lot more testing before they can become tests themselves. But blood tests seem to be the way to go and scientists are furiously trying to find markers like these to identify cancers early.