Featured Research

from universities, journals, and other organizations

New Tool Reveals Molecular Signature Of Cancer And HIV

Date:
October 27, 2004
Source:
Johns Hopkins Medical Institutions
Summary:
Scientists have designed a new molecular tool, dubbed "LigAmp," to pinpoint DNA mutations among thousands of cells, the equivalent of searching for a single typo in an entire library of books. Preliminary studies in a small number of cell lines and body fluids show the ultra-sensitive test may help detect microscopic cancer and HIV drug resistance.

Scientists have designed a new molecular tool, dubbed "LigAmp," to pinpoint DNA mutations among thousands of cells, the equivalent of searching for a single typo in an entire library of books. Preliminary studies in a small number of cell lines and body fluids show the ultra-sensitive test may help detect microscopic cancer and HIV drug resistance.

Related Articles


"Other molecular tests make it very difficult to locate a mutation in a particular cell surrounded by thousands of other cells that don't have the mutation," says James Eshleman, M.D., Ph.D., who led the study with colleagues from the Johns Hopkins Department of Pathology and Kimmel Cancer Center. "LigAmp essentially filters background 'noise' caused by normal cells and reveals specific mutations."

The researchers say that sensitive tests to locate mutations could identify cancer in patients at high-risk for the disease. Such tests could even help detect a recurrence of cancer by monitoring whether the number of mutations rises above a predetermined threshold value.

In addition to cancer detection, the Hopkins mutation-finder appears able to detect drug-resistant HIV. The team tested it on blood samples from a handful of patients with HIV and located DNA mistakes in the virus itself that make it resistant to certain antiretroviral drugs. Results of analyses of the new test are published in the November issue of Nature Methods.

"We designed LigAmp to improve how we look for extremely subtle variations in viral and cellular DNA," says Eshleman, an associate professor of pathology and oncology and associate director for the DNA Diagnostics Laboratory at Johns Hopkins. "The molecular code of normal cells may look identical to cancerous except for a single rung in the DNA ladder-structure."

The test works by creating a molecular "magnet" with an affinity for the DNA mistake, also known as a point mutation. If the mutation is found, the magnet binds to it and inserts a bacterial gene. The bacterial gene serves as a red flag and produces a fluorescent color visible to powerful computer programs.

In their studies, the Hopkins investigators tested LigAmp on colon cancer cell lines, blood from HIV patients, and fluid from cancer patients' pancreatic ducts. Single mutations in colon cancer cells and drug-resistant HIV viruses were detected at dilutions of up to 1 in 10,000 molecules. Mutations of the KRAS2 gene were detected in duct fluid samples from three pancreatic cancer patients, which also corresponded to mutations found in their tumors. LigAmp also located a drug-resistance mutation, called K103N, in blood samples from three HIV patients.

Further analysis of LigAmp with larger sample sizes and blinded panels of clinical samples currently is under way.

"Some initial studies show that we can simultaneously look for different mutations and quantify the number of mutated molecules present. This may help us build panels of cancer markers for screening and determine low or high levels of mutation."

Funding for this research was provided by the Maryland Cigarette Restitution Fund, the National Cancer Institute, and the National Institute of Allergy and Infectious Diseases.

Johns Hopkins colleagues working with Eshleman are Chanjuan Shi, Susan Eshleman, Dana Jones, Noriyoshi Fukushima, Li Hua, Antony Parker, Charles Yeo, Ralph Hruban, and Michael Goggins.

###

Shi, Chanjuan et al, "LigAmp for Sensitive Detection of Single-Nucleotide Differences." Nature Methods, vol 1, n 2, November 2004.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "New Tool Reveals Molecular Signature Of Cancer And HIV." ScienceDaily. ScienceDaily, 27 October 2004. <www.sciencedaily.com/releases/2004/10/041027103641.htm>.
Johns Hopkins Medical Institutions. (2004, October 27). New Tool Reveals Molecular Signature Of Cancer And HIV. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2004/10/041027103641.htm
Johns Hopkins Medical Institutions. "New Tool Reveals Molecular Signature Of Cancer And HIV." ScienceDaily. www.sciencedaily.com/releases/2004/10/041027103641.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
UN: Up to One Million Facing Hunger in Ebola-Hit Countries

UN: Up to One Million Facing Hunger in Ebola-Hit Countries

AFP (Dec. 17, 2014) Border closures, quarantines and crop losses in West African nations battling the Ebola virus could lead to as many as one million people going hungry, UN food agencies said on Wednesday. Duration: 00:52 Video provided by AFP
Powered by NewsLook.com
When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
Why Your Boss Should Let You Sleep In

Why Your Boss Should Let You Sleep In

Newsy (Dec. 17, 2014) According to research out of the University of Pennsylvania, waking up for work is the biggest factor that causes Americans to lose sleep. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins