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Old 03-01-2014, 10:48 AM   #1
'lizbeth
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Post Cancer, from the 100 Most Important Science Ideas


An excerpt from the book 100 Most Important Science Ideas by Mark Henderson, Joanne Baker and Tony Crilly:
Quote:
Cancer

Despite the fact that most common disease are the result of complex interactions between inheritance and our surrounding, the product of nature via nurture, there is one that always features genetics at its core. Rather it is not one disease, but a group of more than 200 – the cancers. Brain and breast tumors, carcinomas of the lung and liver, melanomas of the skin and leukemias of the blood share a common characteristic. They are ultimately disease of our genes.

That may come as something of a surprise, given that cancer is often thought of as an environmental disease. Whether it is sunbeds and melanoma, the human papilloma virus and cervical cancer, asbestos and mesothelioma, or smoking and any cancer you choose, there is overwhelming evidence that environmental influences can contribute, often decisively, to the formation of tumors. All these carcinogens that can seriously damage your health, however, do so in essentially the same way. They damage DNA.

“It would surprise me enormously if in 20 years the treatment of cancer had not been transformed.” Mike Stratton, Cancer Genome Project leader, 2000

Cancer is the result of genetic failure. Every time a cell divides, it must successfully copy its DNA. It is estimated that 100 million million cell divisions take place during an average human lifetime. Every one has the potential to introduce an error into a daughter cell’s genetic code that can turn it cancerous.

In healthy tissue, cell division is a controlled process, ordered by genetic signals that ensure it happens only when it is supposed to. Cancer develops when it starts to run out of control. In every case, the trigger is a copying mistake during cell division, often at a single DNA letter. Many mistakes of this sort are harmless, doing nothing to alter the genome’s function, but when mutations strike in the wrong place, the results can be disastrous.

Oncogenes and tumor suppressors

The genetic errors that start cancer can be inherited or acquired from exposure to carcinogenic chemicals or radiation. To launch the destructive career of a tumor, though, they need to affect two broad categories of gene. The first class are the oncogenes – genes which, when defective, give cells new properties that turn them malignant. The second are the tumor suppressors – the genome policemen, whose job is to spot oncogene mutations and tell malignant cells to kill themselves.

Most cells that acquire oncogene mutations are shut down by their tumor suppressors, and commit suicide by a process called apoptosis. A cell with mutations in both kinds of gene, however, can escape this programmed death and become cancerous, though sequential damage to many different genes is usually required. The cell will divide unchecked, passing its mutant genetic legacy to its progeny, which proliferate to create rogue tissue that can eventually metastasize through the body, damage organs, and kill.

Many of the oncogenes that drive cancer are implicated in tumors found in very different parts of the body. Mutations is the BRAF gene, for instance, are common in both malignant melanomas, in which they are often caused by ultraviolet light, and in colon cancer. The same tumor suppressors are often damaged too – the p53 gene is mutated in almost half of all human cancers. Most inherited mutations that contribute to cancer affect tumor suppressors as well – both BRCA1 and BRACA2 have the role. These defects greatly raise the lifetime risk of cancer by reducing by one the number of genetic hits a cell must take to set it on the path to malignancy.

Genetic therapy

To treat cancer, it is necessary to root out the genetically abnormal cells that cause it, either by killing them with drugs or radiation, or removing them with surgery. All these methods can be pretty brutal: operations such as mastectomies can be disfiguring, while chemotherapy and radiotherapy respectively poison and burn healthy tissue as well as the tumors they are designed to cure. Their side-effects are legion.

These blunt instruments, however, are being supplemented with smarter weapons, and genetics provides the guidance system. If it is possible to characterize the precise genetic mutations that are driving a particular cancer, it is also possible to target these with drugs. A prime example is Herceptin, a drug prescribed to women whose breast tumors in the gene for a receptor called HER-2. The drug binds to this receptor, killing the cancer. It can halve the relapse rate – but only among those patients whose cancers are genetically susceptible to it. In others, it has no effect. Had it been tested in the general population, rather than in a targeted group, it would have never made it through clinical trials.

This is the future of cancer treatment, which a project called the International Cancer Genome Consortium should help to realize. This $1 billion initiative aims to identify all the mutations that drive 50 common types of cancer, so that doctors can pinpoint the precise genetic factors that are responsible for the growth and spread of their patient’s tumors. Cancers could then be treated not so much according to where they occur in the body, but on the basis of the genetic makeup of their rogue cells. We may soon think not of bowel or stomach cancers, but of BRAF-positive or p53-positive tumors.
__________________
Diagnosed 2007
Stage IIb Invasive Ductal Carcinoma, Pagets, 3 of 15 positive nodes

Traditional Treatment: Mastectomy and Axillary Node Dissection followed by Taxotere, 6 treatments and 1 year of Herceptin, no radiation
Former Chemo Ninja "Takizi Zukuchiri"

Additional treatments:
GP2 vaccine, San Antonio Med Ctr
Prescriptive Exercise for Cancer Patients
ENERGY Study, UCSD La Jolla

Reconstruction: TRAM flap, partial loss, Revision

The content of my posts are meant for informational purposes only. The medical information is intended for general information only and should not be used in any way to diagnose, treat, cure, or prevent disease
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