Your Lifestyle, Your Genes and Cancer

 

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Cancer is ultimately a disease of malfunctioning genes. Perhaps 10 percent of all cancers occur in people who have inherited genes that make them vulnerable. In some cases, those genes are so influential the risk of cancer is very high. However, most of us are born with good genes that succeed in flawlessly organizing our growth and development. After all, our genes have been optimized by more than 600 million years of evolution; they ought to work well. During the course of our lifetimes, though, genes are damaged in various cells throughout the body. It is these mutated genes that drive most cancers.

Every cell contains growth-promoting genes called "proto-oncogenes" and growth-stopping genes called "tumor suppressor" genes. Mutations that activate a proto-oncogene can cause the gene to release an unceasing stream of growth-stimulating molecular signals that cause the cell to multiply. Conversely, mutations that inactivate tumor-suppressor genes cause their growth-stopping messages to be silenced. In most human-cancer cells, there are multiple mutations—some that activate oncogenes and some that silence tumor-suppressor genes. In other words, cancer cells have stuck accelerator pedals and faulty brakes. During our lifetime, the cells in our bodies will divide 1016 times—that's 10,000 trillion times—creating 10,000 trillion opportunities for our "start" and "stop" signals to malfunction, and for a tumor to start.

Another important gene, called telomerase, is turned off in healthy cells, causing the cells to die after they have doubled about 50 times. Telomerase is turned on, however, in many cancer cells, which allows them to multiply indefinitely. There are other genes that cause a cell to "commit suicide" when the cell senses that it has been damaged; if such a cell suicide gene becomes disabled, a cancer cell will be allowed to multiply.

Genes also affect a cancerous cell's ability to metastasize—to detach itself from the primary tumor, crawl through the walls of nearby small blood or lymph vessels and spread through the circulation to other parts of the body. Research published in the past year has identified sets of genes that normally are active only when cells in an embryo need to migrate from one part of the embryo to another. In cancer cells that metastasize, these long-silent genes have somehow been activated. The genes make it easy for a cell to detach itself from the tissue around it and they improve the cell's ability to move toward and through the walls of blood and lymph vessels. Recently, a small molecule called microRNA-10b was discovered to powerfully affect the ability of breast-cancer cells to metastasize. This is exciting because, at least theoretically, such small molecules are attractive targets for treatments.

But what causes the various genetic changes that lead to cancer? Mutation-inducing chemicals—mutagens—in our environment can do so. Exhibit A, of course, is tobacco smoke. However, other environmental chemicals that many people suspect of causing cancer—food preservatives, contaminants in our drinking water, pollutants pouring out of smokestacks—rarely do so. In fact, in the developed nations, only 1 to 2 percent of cancers are attributable to such environmental pollutants.

Instead, most cancer-inducing mutations occur when cells damage their own genes accidentally. Each of our cells continuously produces mutation-inducing chemicals as byproducts of its normal metabolism. When our cells generate energy by converting oxygen into water, modified oxygen molecules called "oxygen radicals" are produced. These radicals strike wildly at all the molecules in our cells, including the DNA of our genes. Although our cells have the ability to repair this damage, the protection is not perfect, and so mutations and mutant genes accumulate as we grow older.

Mutations, while necessary, are not sufficient. Something else—something from outside the cancer cell—needs to fan the flames. A cell with several mutations may be primed to become cancerous, or may even be in the sluggish early stages of cancer, but that cell usually needs to be stimulated by additional growth-promoting signals to become a full-blown tumor. In fact, development of the great majority of human cancers is likely to be driven by these non-mutagenic "cancer promoting" molecular signals.

We don't know precisely how the Western diet increases our risk of cancer. The foods we eat contain chemicals that can mutate genes and that therefore could cause cancer. For example, red meat cooked at high temperatures generates potent mutagens called heterocyclic amines. Foods contain many different chemicals, and those chemicals are transformed in our body into many other chemicals, making it very difficult to pinpoint just what it is about the Western diet that raises our risk of cancer. But there is no doubt that it does.

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Member Comments

  • Posted By: JayDub @ 08/05/2008 11:36:48 PM

    Look at this logically. First, my wife, father, uncle, grandmother, grandfather and several cousins had forms of cancer. Some of them lead "clean" lives. Some didn't, and the source of cancer was clear; my father smoked a lot and got lung cancer. I've had to do a lot of research, and have had many conversations with doctors and specialists. But, I am not an "expert".
    However, a few things are undeniably clear. First, we live in a kind of toxic soup; an environment and set of influences we've never historically experienced before. The air, soil, food sources, fertilizers, medications and the science of growing food are all different. And so is the way we process our food. Mix that with genetic tendencies and we have a complex set of interrelated circumstances in which cancer can better find fuel.
    The quote in the article "...just beginning to understand how diet, a healthy body weight and regular exercise can protect us against cancer" is shocking. Don't these things make sense for our general well-being, regardless of cancer? Haven't they always contributed to quality of life, regardless of age or location?
    My wife is completing her radiation for cancer and is doing, thankfully, quite well. What we experienced consistently, though, is an institutional ignorance of how these true fundamentals ??? diet, weight, exercise ??? can affect acquiring, and banishing, the disease. Even the "nutritionists" they sent in were clueless.
    No, you don't have to stop eating red meat or sugar, but you DO have to moderate intake of many foods (like red meat once a month), and approach things like sugar and salt with informed trepidation. Think about it: sugar ain't what it used to be, nor is salt. Salt once had myriad minerals intact, nearly all of which were beneficial to health. Not today! Same with sugar, same with corporately-grown vegetables. Sugar is refined out of benefit then used in nearly everything packaged or cooked. And, the soil is so overworked there???s nothing good left in it.
    So, here's the case for naturally-raised and organic food, animal or plant, as expensive as they are: Heart attacks and cancer cost more than organic food. Do any of you out there - including you research doctors - really know how trace pesticides and engineered DNA play against trace medications in our water, air pollution and the lack of daily nutrition? Of course not. But, doesn't approaching this problem this way simply make sense? If it walks and quacks???
    The facts are we all have certain genetic tendencies, and we are not breathing, eating and medicating the way we once did (and for millions of years before this). The interplay is deadly.
    Be very picky about what you eat. Read every label. Call the numbers on the packaging. It's your body, it's your life. Trust me and the thousands of people and families who???ve been through cancer. You're not doing yourself ??? or society ??? a favor by having that "occasional" Big Mac

  • Posted By: Nins @ 07/07/2008 12:02:48 AM

    Did you know that if McCain is elected you will have to pay income tax on the value of the medical insurance that your employer gives you? Worse still, he is offering a tax break for people who pay their own insurance, BUT only $2,500 for individuals and $5,000 for families.

    Let's say you have a family of four. Your insurance policy costs would be at least $1,500-2,500 per month under a self-pay plan, which cost more than employer group plans. So, you pay $18,000 -$30,000 per year for insurance, and you get to deduct only $5,000 of that. If you paid $25,000 for you insurance, you would be out of pocket $20,000 per year. This is FAR WORSE than the current system, where if you are self employed you can deduct 100% of you medical insurance costs.

    So, if you're not self employed, you would stick with your Employer's plan. Employer plans for a family of four have a value of $900-$1,500 per month totaling 10,800-$18,000 per year. Surprise! On April 15th, you owe tax on all of that as INCOME to you. Say your bracket is 25%, and the value of your Employer medical plan is $14,000. You will OWE THE IRS an additional $3,500, and that's ON TOP of whatever monthly premium you already pay to your employer for your insurance.

    Many analysts say that McCain's new rules would encourage employers to stop offering health benefits. If that happened, then far fewer Americans would be insured than are insured today, because what family of four can afford $18,000-$30,000 out of pocket per year for self-pay health insurance?

    Furthermore, McCain's plan does not require insurance companies to cover pre-existing conditions of people who self-pay their insurance. People under employer group plans have all of their pre-existing conditions covered. This is a hugely unfair aspect of the current system. Insurance companies can afford to cover the pre-existing conditions of the much larger pool of people with group insurance, but they refuse to pay the pre-existing conditions on the smaller pool of self-pay customers. They have been allowed to price gouge the self-pay customers, which is a form of market manipulation that should be illegal.

    So let's say one of your kids had diabetes and you have high blood pressure, then your employer stops offering insurance. You now have to buy your own, but you and your child are INELIGIBLE due to pre-existing conditions. Oh, yeah, they will let you buy the insurance, but you can't use it for any pre-existing condition until you have paid on time every month for two years. And you know what happens at one year and 11 months? You get a letter saying your policy has been cancelled. I have many patients this has happened to.

    McCain's plan SUCKS.

    It does nothing to help middle class working Americans afford or obtain medical insurance. In fact, it makes the current system WORSE.

  • Posted By: Tan Boon Tee @ 06/27/2008 2:43:01 AM

    In 1993, I suffered from nose cancer. Fortunately it was diagnosed early enough before it spread to the brain and other parts of the body. After going through a week of chemotherapy and seven weeks of radiotherapy, I recovered.

    The cause of cancer has always been attributed to a person???s food intake, tobacco consumption, life style, physical constitution and genetic mutation. The various combinations of these factors generate different forms of cancer.
    It was believed that my nose cancer was partly due to the excessive amount of salted fish I had in my younger years, and Chinese are said to be more prone to have this kind of cancer compared with other races.

    With the advancement of medicine and biotechnology, chances of surviving this life-threatening malignancy are growing. I pray that it will be curable in the not so distant future.

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Your Lifestyle, Your Genes, And Cancer

New research explores the complex interactions that cause our most dreaded disease. A look into some of the steps you can take to reduce your risk.