As Siddhartha Mukherjee detailed in his Pulitzer Prize-winning “biography of cancer,” The Emperor of All Maladies, humans may have lived with cancer for millennia but, until recently, we knew next to nothing about it. Now, it seems the every day brings promising new research on cancer’s causes, its weaknesses and ways to thwart it. Some developments, such as vaccines for cervical cancer, are now established; others, such as experimental therapies using viruses, are still very much experimental. We also know now that restraint in diagnosing and treating cancer is better than aggressive therapies that carry harmful side effects.

We compiled a list of cancer breakthroughs and new directions that have happened in recent years (though some of them obviously have roots in earlier decades).

1. Vaccines can protect against some cancers

Researchers have known for years that viruses cause some cervical and liver cancers. But immunizing people against those viruses, and thus immunizing against cancer, has changed the prevention landscape. In 2006, the first vaccine for some forms of the human papilloma virus (HPV) – which has been shown to cause most cervical cancers – won approval from the U.S. FDA. The CDC now recommends that 11 and 12 year-old girls receive the vaccine, Gardasil and Cervarix, which has also been shown to protect against anal, vaginal and vulvar cancers.

2. Vaccines can also fight cancer

In 2010, the FDA approved Provenge, which can be used to treat advanced prostate cancer. The “vaccine” is made by activating the patient’s white blood cells by exposing them to a protein in prostate cancer cells. The cells are reinjected into the patients after three days in an attempt to fight the disease. It is not a cure, however, and the vaccine can only be used for men with a particular type of cancer that is no longer responding to hormone therapy. Men who received the vaccine lived four months longer, which health officials consider a good start.

3. Viruses may be useful in fighting cancer

Cancer cells jettison genetic code in their rush for unchecked growth, including machinery that protects against viruses. Canadian researchers have capitalized on this weakness in cancer cells by using a genetically modified version of vaccinia – a relative of smallpox – to attack tumors but leave healthy cells unharmed. In early studies, the vaccines have shown promise in attacking metastatic tumors. Other researchers have used other viruses to attack aggressive brain tumors called gliomas. It’s too early to declare this an effective therapy, but it’s promising.

4. Some cancers may be better left untreated

In a surprising turn, Swedish researchers in 2010 found that men with early stage prostate cancer rarely die from the disease. And those men who didn’t receive treatment were only slightly more likely to die from the cancer. The idea that some patients might do better with “watchful waiting” and that the side effects of treatment – surgical removal of the prostate, radiation – might be worse than leaving the disease alone was shocking to some. Still, this discussion is by no means settled, since living with untreated prostate cancer is stressful and there is considerable gray area in determining whether a cancer is early stage or more aggressive.

5. The genome may hold the key to some cancers

As scientists apply sophisticated tools to studying the human genome, they have learned about what genetic variations are associated with cancer. Researchers at the Mayo Clinic have found that two common genetic variations on one gene can lead to a higher risk for lung cancer in people who have never smoked. Other variations have been associated with certain brain cancers. This information could, down the road, lead to better cancer prevention.

6. The “gene desert” also holds clues to cancer

Scientists have thought for years that the human genome was 98 percent junk, or noncoding, DNA. Recent research has shown that this area could actually contain important information that can have as yet unexplained influence on cells.

7. Cancer screening is a double-edged sword

Here’s a surprising statement: all screening tests do harm, but some may also do good as well. Harm from a screening test can be the stress associated with a false positive mammogram result or an unnecessary biopsy. And over the course of 10 years, the cumulative risk of a false positive is almost 50 percent, according to an widely cited study. In 2009, the U.S. Preventive Services Task Force revised its guidelines to recommend that women under 50 should not get routine screening mammograms. Women should instead make their own decisions about the risks and benefits of screening, according to the Task Force.

8. It’s tough to tell sometimes what causes or prevents cancer

We’ve always known this, but in the past decade, the science on what is and isn’t carcinogenic has gotten complicated. Take the example of cell phones: does the nonionizing radiation from phones lead to brain cancer? The World Health Organization has said that radiofrequency fields are “possibly carcinogenic to humans.” Other organizations, including the CDC have concluded that the available evidence does not support a link. The British newspaper Daily Mail even has a website that catalogs all of the stories it has published on every food, object or activity that causes or prevents cancer. Sometimes it’s hard to know.

9. Targeted therapy is a potent weapon in the war on cancer

Targeted cancer therapies block cancer’s growth by attacking certain molecules in tumors. This approach is distinct from traditional therapies that attack all rapidly dividing cells. The best known targeted therapy, Gleevec, was approved by the FDA in May 2001 and is now approved for ten cancers. At the time, Time magazine called it “new ammunition in the war against cancer.” These therapies can give physicians a better way to tailor specific treatments for different kinds cancer.

10. Low-tech treatments can work wonders

A technique that involves brushing vinegar on a woman’s cervix to reveal precancerous spots then freezing the spots off with a supercooled metal probe could save tens of thousands of lives in poor and middle income countries. This low-tech treatment, called VIA/cryo was developed at Johns Hopkins medical school and is simpler and less expensive than a Pap smear. It also doesn’t require women to be reachable if a biopsy from an abnormal Pap smear discovers precancerous lesions.

Top image: The gene desert isn’t as bare as we thought. Photo courtesy Flickr user Moyen Brenn