sábado, 5 de julio de 2008

Cancer cells extracted from blood

Cancer cells extracted from blood
Last updated: Friday, July 04, 2008
An experimental process that snags lung cancer cells from a blood sample could give doctors real-time feedback on the most effective therapy, researchers reported.
Dr Daniel Haber of the Massachusetts General Hospital Cancer Centre and Harvard Medical School and colleagues were able to extract blood-borne cancer cells from 27 volunteers with non-small-cell lung cancer that had spread.

They found that changes in the number of circulating cancer cells correlated with the effectiveness of a patient's treatment and were also able to track genetic changes in the tumour cells over time.

Enables individualised treatment
The study, reported on the Web site of the New England Journal of Medicine, is another step in the quest for individualised medicine, where doctors strive to quickly assess a tumour, choose the most effective treatment, and alter that treatment as cancer cells adapt.

In December, the same group reported in Nature that their circulating tumour cells, or CTC, chip could extract malignant cells from people with breast, prostate, pancreatic and colorectal cancers, as well as lung tumours.

Now they say they have used the collected cells to identify specific mutations, which may someday help guide therapy.

"Right now you take your best guess as to what kind of treatment would work for a patient's cancer, give it to them for two or three months, and then repeat a CAT scan to see if it worked," Haber said in a telephone interview.

Continuous monitoring
"If there were a way of measuring an earlier response, that would be fantastic," he added. "The CTC chip offers the promise of non-invasive continuous monitoring."

Doctors have many choices of drugs to treat lung cancer, the world's leading cancer killer, taking the lives of 1.2 million people a year.

Yet only 15 percent of patients live five years or more.

"Treating patients with drugs specific to their particular tumour is likely to yield increased response rates, prolonged survival, and a decrease in the number of patients who are exposed to toxic drugs unnecessarily," Dr Joan Schiller of the Lung Cancer Alliance wrote in a commentary.

Schiller, of the University of Texas Southwestern Medical Centre in Dallas, said there are practical questions about whether enough cells can be extracted to make the technique effective and whether it will work for other types of tumours.

Haber said he believes it will.

The CTC chip, licensed to the privately held CellPoint Diagnostics in Mountain View, California, is 100 times more sensitive than a US Food and Drug Administration-approved technique that uses magnetic beads to try to extract cancer cells, according to Haber.

The test requires a 10 ml blood sample - just two teaspoons. It takes about eight hours to send the blood across the 80 000 tiny columns so specially designed antibody glue can latch onto passing cancer cells.

Haber said his team is trying to further automate the process to make it faster.

"If the cells are alive on the chip, which they are, and if you have a new 'smart' drug that's supposed to attack a particular protein, you can test in the cell if the protein is being attached by the drug," he said. – (Gene Emery/Reuters Health)

Lifestyle triggers genetic change

Esta es una noticia extraordinaria.

Lifestyle triggers genetic change
Last updated: Wednesday, June 18, 2008
Comprehensive lifestyle changes, including a better diet and more exercise, can lead not only to a better physique, but also to swift and dramatic changes at the genetic level, US researchers said.

In a small study, the researchers tracked 30 men with low-risk prostate cancer who decided against conventional medical treatment such as surgery and radiation or hormone therapy.

The men underwent three months of major lifestyle changes, including eating a diet rich in fruits, vegetables, whole grains, legumes and soy products, moderate exercise such as walking for half an hour a day, and an hour of daily stress management methods such as meditation.

As expected, they lost weight, lowered their blood pressure and saw other health improvements. But the researchers found more profound changes when they compared prostate biopsies taken before and after the lifestyle changes.

Dramatic changes in genes noted
After the three months, the men had changes in activity in about 500 genes - including 48 that were turned on and 453 genes that were turned off.

The activity of disease-preventing genes increased while a number of disease-promoting genes, including those involved in prostate cancer and breast cancer, shut down, according to the study published in the journal Proceedings of the National Academy of Sciences.

The research was led by Dr Dean Ornish, head of the Preventive Medicine Research Institute in Sausalito, California, and a well-known author advocating lifestyle changes to improve health.

"It's an exciting finding because so often people say, 'Oh, it's all in my genes, what can I do?' Well, it turns out you may be able to do a lot," Ornish, who is also affiliated with the University of California, San Francisco, said in a telephone interview.

Findings not limited to men with prostate cancer
"'In just three months, I can change hundreds of my genes simply by changing what I eat and how I live?' That's pretty exciting," Ornish said. "The implications of our study are not limited to men with prostate cancer."

He said the men avoided conventional medical treatment for prostate cancer for reasons separate from the study. But in making that decision, they allowed the researchers to look at biopsies in people with cancer before and after lifestyle changes.

"It gave us the opportunity to have an ethical reason for doing repeat biopsies in just a three-month period because they needed that anyway to look at their clinical changes (in their prostate cancer)," Ornish said. – (Reuters Health)

June 2008