Dear Doctor: Is it just me or has it been forever since we've seen any real advances in cancer treatments? The new miracle drugs work only in very specific cases and the rest of us cancer patients are left with 20th-century treatments. Are there breakthroughs we aren't hearing about?

Dear Reader: When it comes to big cancer breakthroughs, it can seem like there isn't much new to report. As you correctly point out, the newest treatments emerging from the fields of precision medicine and immunotherapy are geared to cancers with very specific characteristics. However, when it comes to the future of cancer treatment, there's a revolution in progress.

Powered by the decoding of the human genome, which has allowed scientists to explore the human body at the cellular level, our understanding of what cancer is, how it behaves and how to stop it is growing exponentially. One bright spot is recent research funded by the National Institutes of Health, which has collected detailed data about more than 10,000 tumors arising from 33 different types of cancer. The analysis of that data, known as the PanCancer Atlas, is found in a collection of 27 different scientific papers. The information contained within was 10 years in the making. Taken together, these papers outline the findings of more than 150 researchers and examine the selected cancers at the molecular level.

One important advance has been how we talk about various cancers. Rather than approach tumors based solely on the part of the body where they originate, the shift is to classify them based on their molecular similarities to one another. For instance, after analyzing the tumors in the database, it was discovered that one type of tumor with a specific genetic profile was located in 25 different parts of the body. According to the body-location way of thinking, this one tumor would have had multiple treatment approaches.

Researchers also found a marked diversity in the genetic glitches in the tumors they studied, in the ways that the tumors grow, and in the cellular pathways they either use or outright hijack to ensure their survival. This line of inquiry has made possible the creation of important sub-groupings of various cancers, which aids in the search for targeted treatments. It has also helped scientists to identify potential vulnerabilities in various types of cancer.

Instead of focusing on how to poison the rogue cells with radiation or chemotherapy, researchers are now looking at ways to starve tumors, weaponize the immune system and even rewrite the tumor's own genetic code. So-called "smart" cancer drugs, which just a few years ago seemed like a fantasy, are now in the testing stages. One promising line of inquiry is looking into ways to harness tiny microparticles to deliver cancer-fighting drugs directly to the tumor, and even to deliver tiny imaging agents for more precise visualization.

Many of the cancer researchers and oncologists we know agree that we are presently in the midst of a revolution into our understanding of this complex and challenging disease. The "war on cancer" that we grew up hearing about may not yet be won, but battle by battle, things have never looked better.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My son, who plays several sports, recently broke his right arm. Now he's worried that the muscles will waste away while it heals. I read that exercising his left arm could help his broken arm. When I told him this, he scoffed. It does seem crazy, but is it true?

Dear Reader: Improbable as it sounds, a new study found that when a limb on one side of the body is immobilized, as in the case of your son's broken arm, it's possible to preserve muscle strength and size by exercising the corresponding limb on the other side of the body.

This is a phenomenon known as "cross education," which has been written about since at least 1894. Since then, a number of studies have backed up the existence of cross education. Whether through voluntary muscle contractions through exercise, imagined contractions via targeted visualization or contractions that were electrically stimulated, activating the muscles of the opposite limb preserved both strength and muscle mass in the immobilized body part.

In this newest study, researchers in Canada studied the forearms of 16 male and female college students for four weeks. All were right-handed, and none had recent experience with resistance training. Using CT scans, ultrasound and a weight machine, the researchers measured the dimensions and strength of the muscles in the participants' forearms. The students were then fitted with casts on their left forearms to immobilize their wrists, hands, thumbs and fingers up to the knuckles. Each was randomly assigned to either a training group or to a control group. The training group took exercise classes three times a week that focused on certain muscle groups in the wrist, hand and forearm of the free limb. The control group did not take part in those classes and was asked to refrain from any other exercise as well.

A month later, after the casts were removed, measurements showed that participants in the control group had lost about 20 percent of the strength in their left forearms and had lost 3 percent of their muscle mass. For the participants who had exercised those specific muscle groups in their right forearms, however, both strength and mass measurements in their immobilized forearms were virtually unchanged. Even more interesting was the fact that the muscle groups in the right hand that were deliberately not exercised had measurably atrophied in the left hand. Only the same muscles that were exercised in the free limb maintained their strength and mass in the limb that was in a cast.

How and why cross education takes place is not yet known. Although sensors placed inside the casts of the resistance training group showed that there was indeed some muscular contraction taking place while the students exercised their free hands, these were too weak to have a physical effect.

So what's going on? Most popular among the many theories that have been floated is the idea that something is happening in the neural circuits of our brains. In the meantime, let your son know that, thanks to cross education, he has a way to emerge from his cast stronger than he expected.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I know that plain old soap and water are best for washing your hands, but sometimes it's either do nothing, or use an alcohol-based hand sanitizer. So, I'm wondering, though they promise to kill "99.9 percent of germs," just how effective are hand sanitizers with respect to disease-causing viruses like the flu?

Dear Reader: A hand sanitizer is a liquid made with a specific chemical composition to decrease the presence of potentially infectious agents like bacteria, fungi and viruses. You've asked about alcohol-based hand sanitizers, and since it's widely agreed that formulations with an alcohol content of 60 percent or higher are the most effective, these are the ones we'll be referring to in our answer. When it comes to specifics regarding which infectious agents these hand sanitizers kill or abate, though, things can become a bit murky.

A study done in Boston in 2005, said to be among the first into the efficacy of alcohol-based hand sanitizers, found no difference in the spread of respiratory infections between the families who used hand sanitizers and those in the control group who didn't. Subsequent other studies over the years, as well as a repeat of the Boston study, found the same thing. As we've discussed here in previous columns, infections like the influenza virus are most often spread via the aerosolized droplets from an infected person's cough or sneeze. These hang in the air, where they can be breathed in and thus cause a new infection.

Although hand sanitizers can neutralize an impressive range of microbes, they don't work against everything. Even when you've used the right amount and the proper technique, germs like Cryptosporidium, norovirus and Clostridium difficile may persist. Studies have shown that hand washing with soap and water is most effective for these types of germs.

The federal Centers for Disease Control and Prevention agree with you that soap and water is the best hand-washing method. However, when you need a Plan B, do reach for the alcohol-based hand sanitizer. Those with an alcohol content lower than 60 percent, however, and those that are not alcohol-based don't work as well for all germs. They may only reduce and not eliminate the germs on your hands and may encourage the infectious agents to develop resistance to the sanitizer.

As with hand washing, proper technique matters when you're using a liquid hand sanitizer. Be sure to read the label of your particular product and use the full amount indicated. Dispense into one palm, then rub continuously to spread the liquid on all of the surfaces of your hands until the alcohol has evaporated, and your hands are dry.

When you do use a liquid hand sanitizer, it's important to start out with clean hands. When hands are dirty or greasy, the products are less effective. It may seem self-evident, but never ingest a hand sanitizer. And while they can be effective against a range of microbes, when it comes to cleaning off noxious chemicals, like a bug spray or weed killer, skip the hand sanitizer. Instead, go for a thorough wash and rinse (and repeat) with good old soap and warm water.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)