The screen, developed by Sara Sukumar, Ph.D. and Mary Jo Fackler, Ph.D., first separates cells from fluid, then sifts through the cells' DNA for chemical tags on certain genes associated with cancer.
Reporting in the June 1 issue of Clinical Cancer Research, the scientists say they have tested their screening tool on breast fluid, in search of cells shed from growing tumors.
"This screening method can see what the eye cannot see," says Sukumar, who is the Barbara B. Rubenstein Professor of Oncology at the Johns Hopkins Kimmel Cancer Center. "It can be a valuable tool, in combination with pathological review, for breast cancer as well as other diseases where fluid can be obtained relatively easily, such as lung, head and neck cancers, pancreatic and cervical cancers."
Pathologists look for telltale shapes of cells to determine if cancer is present, but molecular changes in cells, especially for early cancers, are beyond the reach of even the most powerful microscopes.
Sukumar's test searches for unusually high amounts of chemical tags embedded by a process called methylation within critical regions of DNA. The tags attach to the "on" switch of genes which starts the message-manufacturing process. Cancer cells have abnormal levels of methylation, which turns the gene switch off halting the assembly line of critical proteins found in normal cells.
The Hopkins test, called quantitative multiplex methylation-specific PCR or QM-MSP, determines the percentage of methylation present in each of five to ten cancer genes. The percentages are added together for a cumulative score, which is compared to a threshold value. Levels above the threshold indicate the potential presence of cancer cells and below threshold suggests that the samples are normal.
In the study, Hopkins researchers compared the cancer-detection rates of their QM-MSP test versus microscopic review by a pathologist on breast fluid samples. The fluid samples, taken from high-risk women or those diagnosed with breast cancer, were obtained through a process called ductal lavage, a saline wash via a catheter threaded through openings in the nipple leading to the vast network of breast ducts.
Cytopathologists correctly identified seven of 21 (33 percent) fluid samples containing cancer, and ruled out the disease in nearly all cases negative for cancer (92 of 93 samples, 99 percent). QM-MSP doubled the cancer detection rate to 71 percent by spotting 15 of 21 samples known positive for cancer. Of 76 samples negative for cancer, QM-MSP concurred on 63 (83 percent).
"Now that we know the screening tool is effective in finding cancer cells within breast duct fluid, we need to improve the accuracy of obtaining the fluid," says Sukumar, who believes that their gene screen may miss cancers if they overlook any hidden breast ducts.
Improvements in getting an accurate representation of fluid from all the breast ducts are underway by other investigators, and include using sound waves to locate all the ducts.
"Source":[ http://www.medicalnewstoday.com/medicalnews.php?newsid=47432]
Gene cancer tests 'need review' -
Decisions over who to test for a high-risk breast cancer gene should not be made solely on the basis of family history, US research suggests
Predictions as to whether a woman may develop hereditary breast cancer are often reached by counting the number of female relatives with the disease
But this excludes women who do not have many female relatives in whom the disease could have manifested itself
The Journal of American Medicine study said testing criteria needed reviewing
The study looked at 306 women who had breast cancer and, crucially, no close female relatives with the disease
BRCA genes were found in 13
The genes BRCA1 and BRCA2 account for about 10% of inherited breast cancers, and they are also associated with an increased risk of ovarian cancer
BBC
(21.6.2007)
Breast cancer in a test tube -
UK researchers have developed a three-dimensional model of human breast cancer in the laboratory
The model, which includes normal cells and tumour cells, should help experts understand how breast cancer develops in the early stages
And it may replace the need for experiments in animals, the team at Queen Mary, University of London said
More women are being diagnosed with cancer in the early stages and the model could lead to new treatments
The model replicates a specific type of early breast cancer - known as ductal carcinoma in situ (DCIS)
Whole article BBC NEWS
(10.5.2007)
Important cause of breast cancer found -
Researchers of the University Hospital, Basel and the Hamburg-Eppendorf University Hospital have discovered an important cause of the onset of breast cancer
It has been long known that the abnormal increase of the copy number of genes, the so-called gene amplification, plays a role in the onset of breast cancer
Whole article www
(24.4.2007)
Scientists Stop Genes that Help Breast Cancer to Spread -
US scientists have demonstrated a way to stop breast cancer spreading to other parts of the body by either switching off the genes involved or blocking them with drugs
Tumours formed from cancer that has spread or metastased from the primary site to other parts of the body cause 90 per cent of cancer deaths
The process of metastasis or cancer spread is still much of a mystery to scientists
Dr Joan Massagué from the Memorial Sloan-Kettering Cancer Center in New York, US, has been working in this field for some time
Whole article www
(13.4.2007)
