Bad News for Smokers

June 12, 2015 by

By Medical Discovery News

June 5, 2015

Person smoking a cigarette

Smoking isn’t the only thing that raises your risk of lung cancer. As it turns out, your DNA can have that effect too.

A scientific study scanned the genomes, the entire genetic code, of 11,000 people of European descent in an effort to identify if there was any correlation between gene sequences and a common form of lung cancer, non-small cell carcinoma. They discovered that variants of certain genes increase a person’s susceptibility to developing lung cancer, especially in smokers.

One of the three gene variants they identified, named BRCA2, can double a smoker’s chance for developing lung cancer. BRCA2 is a tumor suppressor gene. It encodes a protein involved in the repair of damaged DNA, which is critical to ensure the stability of cell’s genetic material. When cellular DNA is damaged, there are several ways for the body to detect and repair that damage. If the damage to DNA cannot be repaired, then the cell is programmed to die by a process called apoptosis in order to prevent the damage being passed on to its daughter cells.

Like other tumor suppressor genes, the BRCA2 protein helps to repair breaks in DNA. It also prevents damaged cells from growing and dividing too rapidly. Variants of BRCA2 associated with breast, ovarian, and now lung cancers produce proteins that do not repair DNA damage properly. This causes cells to accumulate additional mutations, which can lead to cells that grow and divide uncontrollably. Such mutations lead to an increased risk of developing cancer.

Scientists have discovered over 800 mutations of BRCA2 that cause disease, including breast, ovarian, lung, prostate, pancreatic, fallopian, and melanoma cancers. Most of the mutations result from the insertion or deletion of a few letters of genetic code into the part of the gene that code for a protein. This disrupts the production of the BRCA2 protein and results in a shortened and nonfunctional form of the BRCA2 protein.

Lung cancer is a leading killer of Americans. Nearly 160,000 Americans will die from lung cancer this year, representing 27 percent of all cancer deaths. Active smoking causes close to 90 percent of lung cancers.

The good news from this discovery is that since scientists first linked BRCA2 to an increased risk of breast cancer, new therapies have been developed. Current treatments for breast and ovarian cancers could be effective with BRCA2-associated lung cancers, such as PARP inhibition.  PARP1 is another protein involved in repairing DNA damage. When one of two strands of DNA are broken or nicked, PARP1 moves to the region and recruits other proteins to the site to repair the damage. Many chemotherapy agents kill cancer cells by inducing DNA damage in the tumor and inhibiting PARP1. This doesn’t allow cancer cells to repair damage and makes them more susceptible to chemotherapy and radiation therapy. Now that we know this gene is linked to lung cancer, such therapies may be more effective in treating lung cancer and saving lives.

For a link to this story, click here.

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More Bad News for Smokers

October 27, 2014 by

Oct. 24, 2014

By Medical Discovery News

Lung X-ray

Smoking isn’t the only thing that raises your risk of lung cancer. As it turns out, your DNA can have that effect too.

A scientific study scanned the genomes, the entire genetic code, of 11,000 people of European descent in an effort to identify if there was any correlation between gene sequences and a common form of lung cancer, non-small cell carcinoma. They discovered that variants of certain genes increase a person’s susceptibility to developing lung cancer, especially in smokers.

One of the three gene variants they identified, named BRCA2, can double a smoker’s chance for developing lung cancer. BRCA2 is a tumor suppressor gene. It encodes a protein involved in the repair of damaged DNA, which is critical to ensure the stability of cell’s genetic material. When cellular DNA is damaged, there are several ways for the body to detect and repair that damage. If the damage to DNA cannot be repaired, then the cell is programmed to die by a process called apoptosis in order to prevent the damage being passed on to its daughter cells.

Like other tumor suppressor genes, the BRCA2 protein helps to repair breaks in DNA. It also prevents damaged cells from growing and dividing too rapidly. Variants of BRCA2 associated with breast, ovarian, and now lung cancers produce proteins that do not repair DNA damage properly. This causes cells to accumulate additional mutations, which can lead to cells that grow and divide uncontrollably. Such mutations lead to an increased risk of developing cancer.

Scientists have discovered over 800 mutations of BRCA2 that cause disease, including breast, ovarian, lung, prostate, pancreatic, fallopian, and melanoma cancers. Most of the mutations result from the insertion or deletion of a few letters of genetic code into the part of the gene that code for a protein. This disrupts the production of the BRCA2 protein and results in a shortened and nonfunctional form of the BRCA2 protein.

Lung cancer is a leading killer of Americans. Nearly 160,000 Americans will die from lung cancer this year, representing 27 percent of all cancer deaths. Active smoking causes close to 90 percent of lung cancers.

The good news from this discovery is that since scientists first linked BRCA2 to an increased risk of breast cancer, new therapies have been developed. Current treatments for breast and ovarian cancers could be effective with BRCA2-associated lung cancers, such as PARP inhibition.  PARP1 is another protein involved in repairing DNA damage. When one of two strands of DNA are broken or nicked, PARP1 moves to the region and recruits other proteins to the site to repair the damage. Many chemotherapy agents kill cancer cells by inducing DNA damage in the tumor and inhibiting PARP1. This doesn’t allow cancer cells to repair damage and makes them more susceptible to chemotherapy and radiation therapy. Now that we know this gene is linked to lung cancer, such therapies may be more effective in treating lung cancer and saving lives.

For a link to this story, click here.

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Warning: Third-hand Smoke

September 13, 2014 by

Sept. 5, 2014

By Medical Discovery News

Smoke

Science has long proven that smoking is bad for you and those around you, with 90 percent of lung cancer cases caused by smoking. Even second-hand smoke is dangerous enough to warrant banning smoking in public places. The idea of third-hand smoke premiered in 2009, and scientific evidence shows that it too can harm human health.

Third-hand smoke is the many toxic compounds from tobacco smoke that settle onto surfaces (particularly fabrics) such as carpet, furniture, and the inside of a car. Researchers have identified chemicals in third-hand cigarette smoke called NNA and NNK that can bind to DNA, a person’s genetic information, and cause damage and mutations that could lead to cancer.

There are 4,000 known pollutants in cigarette smoke including a large number that cause DNA damage. Many of them have been found in the carpets, walls, furniture, dust, clothing, hair, and skin of smokers long after they’ve smoked a cigarette. The pollutants from smoke can accumulate over time, making the environment increasingly toxic. Mainstream smoke has more than 60 known carcinogens, which cause cancer, and other toxins, many of which are present in second- and third-hand smoke. Nonsmokers are exposed to these toxic compounds when they inhale, touch, or ingest them off of surfaces containing third-hand smoke. To make matters worse, some of the smoke residue can undergo a chemical transformation into secondary compounds when it interacts with other indoor pollutants, like ozone and nitrous acid. For example, nicotine reacts with ozone in the atmosphere to produce byproducts and ultrafine particles that can trigger asthma attacks.

Other secondary products such as NNA and a related compound called NNK are also formed. A recent study aimed to discover what level of third-hand smoke mutagens and carcinogens a nonsmoker might be exposed to in realistic scenarios, and whether these levels would be high enough to cause damage to DNA or other adverse effects. Unrepaired DNA damage can lead to mutations and increase the risk of developing cancer. They concluded that human cells exposed to third-hand smoke or secondary compounds had increased DNA damage within 24 hours. These results provide evidence that third-hand smoke does include carcinogens from cigarette smoke and the environment. The study also showed that NNA and NNK have damaging effects on developing lungs, making them particularly harmful to infants.

Smokers themselves are giving off third-hand smoke toxins, so going outside to smoke helps but is no solution. It is unclear how long toxic third-hand smoke compounds continue to be a risk. Depending on the compound, they may linger for hours, days, weeks, or longer. When smokers quit they should take steps to rid their homes and vehicles of third-hand smoke. This is potentially a time-consuming and expensive proposition but it is worth doing.

In 2011, 44 million American adults smoked cigarettes and 34 million of them smoked every day. Smoking causes one in five deaths, killing nearly 500,000 people in the U.S. every year. That is more deaths than HIV, illegal drugs, alcohol, motor vehicle accidents, and firearms combined. Is it really worth it?

For a link to this story, click here.

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Are E-cigarettes Safe?

March 11, 2012 by

By Medical Discovery News

Dec. 10, 2011

Are e-Cigarettes Safe?Most people would be flabbergasted to see anyone smoking inside an office, a hospital waiting room or an airport. Yet, lately, people are smoking indoors — not traditional cigarettes, but e-cigarettes.

These are smokeless cigarettes that can look like the real thing, a pen or even a USB stick. What they all do is deliver nicotine to the smoker in a vapor form. A rechargeable battery powers a heating element that vaporizes the nicotine in a replaceable cartridge so that what’s inhaled just looks like smoke.

Some e-cigarette companies claim the devices are safer and can help smokers quit. But critics say the companies’ statements are unproven and their health claims are unsubstantiated.

It is true that e-cigarettes do not contain the over 4,000 chemical compounds created by a burning cigarette. Many of these are toxic and/or carcinogenic. Tar, carbon monoxide, nitrogen oxides, hydrogen cyanide and ammonia are all in regular cigarette smoke.

However, nicotine itself is dangerous and highly addictive, and with e-cigarettes, smokers may not know how much of it they’re getting. A lack of regulation and quality control means the amount of nicotine in each drag of an e-cigarette is inconsistent. The U.S. Food and Drug Administration determined that since e-cigarettes are not considered a drug delivery device, the agency has no jurisdiction over them.

Yet the administration issued a health warning about e-cigarettes after its tests show they contain harmful chemicals such as diethylene glycol, a component of antifreeze that’s toxic to humans and is banned in food and drugs. There were also detectable levels of a known carcinogen called nitrosamine and other toxic chemicals that users could potentially inhale.

Even if, as some enthusiasts claim, e-cigarettes can help a smoker quit, could it also entice young people to start? Health experts and the administration have both expressed concern e-cigarettes are marketed toward young people since the devices come in pink, gold or blue with flavors such as chocolate and bubble gum. Plus, the products’ labels don’t have a  health warning.

Since e-cigarettes are unregulated and not covered by federal tobacco laws, they can be sold online and in mall kiosks. They’re also cheaper than regular cigarettes. Because of this, they’re easily accessible to children and young adults.

Some e-cigarette makers go so far as to make unsubstantiated health claims on their websites and printed materials. That’s why Australia, Canada, Israel and Hong Kong have banned them on the grounds they have not been sufficiently tested for safety. New York City is pushing to become the first city to ban them.

For scientists, those are enough reasons not to try an e-cigarette. At the very least, wait until science shows what is in them before smoking one, or better yet, choose not to smoke at all.

Click here for a link to this article.

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