Featured Research

from universities, journals, and other organizations

When Does A Mole Become A Melanoma?

Date:
February 19, 2005
Source:
Children's Hospital Boston
Summary:
Researchers at Children's Hospital Boston and the Dana-Farber Cancer Institute have found an important clue about the origins of the deadly skin cancer melanoma. Using black-and-white-striped zebrafish to model human melanoma, they showed that a specific mutation in a gene called BRAF is critical to the development of moles, and when combined with a separate mutation, leads to cancer.

Dr. Leonard Zon, along with postdoctoral fellow Dr. Elizabeth Patton and colleagues, genetically engineered this zebrafish to make the mutated form of human BRAF, which caused the fish to develop black-pigmented moles on its skin. When the fish were also made to be deficient for a gene called p53, which suppresses tumor growth, the moles developed into invasive melanomas resembling human cancers. The researchers' findings appear in the February 8th issue of Current Biology. (Still image from video, courtesy of Dr. Leonard Zon, Children's Hospital Boston)

Researchers at Children's Hospital Boston and the Dana-Farber Cancer Institute have found an important clue about the origins of the deadly skin cancer melanoma. Using black-and-white-striped zebrafish to model human melanoma, they showed that a specific mutation in a gene called BRAF is critical to the development of moles, and when combined with a separate mutation, leads to cancer. Their findings appear in the February 8th issue of Current Biology.

Melanoma is now an epidemic cancer: its incidence is rising faster than that of any other cancer, doubling every 10-20 years. When melanoma is metastatic, or spreads to other organs, the average life expectancy is only 6-10 months. Previous studies have indicated that the BRAF gene is mutated in about 75 percent of melanomas, but until this study, no one knew its role, if any, in causing the cancer.

Dr. Leonard Zon, a Howard Hughes Medical Institute investigator in the Children's/Dana-Farber Division of Hematology/Oncology, postdoctoral fellow Dr. Elizabeth Patton, and colleagues genetically engineered zebrafish to make the mutated form of human BRAF. The mutant fish developed black-pigmented moles on their skin, but none developed melanoma. When the fish were also made to be deficient for a gene called p53, which suppresses tumor growth, the moles developed into invasive melanomas resembling human cancers. When cells from these tumors were injected into healthy zebrafish, they too developed melanomas.

"We now know that BRAF, when activated, is sufficient to make moles," says Zon. "We also know that it's insufficient to make cancer – you need other mutations, like a deficiency in the p53 tumor suppressor gene, to get melanoma."

Other animal models of melanoma exist, but the zebrafish is an exceptionally good one: its genome is very similar to the human genome and has been fully sequenced, so all its genes are known. The zebrafish is also very easy to study -- females have 300 babies a week, allowing scientists to very quickly create genetic variations and see the results. In fact, tumors are readily visible in zebrafish, allowing researchers to watch them progress. The fish can also be made to display the effects of gene mutations visually through genetic tricks that make the affected cells and tissues fluoresce. "The visual nature of the fish makes it an attractive model for studying cancer," adds Zon. "We can track a cancer and follow the fate of individual cells as the tumor grows and spreads." Now that the zebrafish model has been created, Zon's team will use it to examine how melanomas metastasize, and to look for other gene mutations besides the p53 mutation that participate in transforming moles into malignant melanomas.

"Some of these genes may lead us to excellent pharmaceutical targets for treatment of melanomas," Zon says.

Once these targets are identified, the zebrafish can be used to test potential anti-melanoma drugs that hit the targets. Researchers will also be able to test the effects of risk factors for human melanoma, such as exposure to ultraviolet radiation, and how they interact with gene mutations to cause disease.

Finally, Zon, who also directs the Children's Hospital Boston Stem Cell Program, will use the fish to learn more about cancer stem cells. Most tumor cells, when transplanted, can't give rise to a new cancer because they lack the capacity to divide and multiply. But tumors often have a subgroup of cells that can self-renew, as stem cells do, and create a new cancer -- as seen in these melanoma experiments. Studying these cells may turn up genes involved in metastasis, for example. "We're hoping to look at cancer as a stem cell problem," says Zon.

###

Children's Hospital Boston is home to the world's largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults for over 100 years. More than 500 scientists, including eight members of the National Academy of Sciences, nine members of the Institute of Medicine and 10 members of the Howard Hughes Medical Institute comprise Children's research community. Founded in 1869 as a 20-bed hospital for children, Children's Hospital Boston today is a 325-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children's also is the primary pediatric teaching affiliate of Harvard Medical School. For more information about the hospital visit: http://www.childrenshospital.org/research/.


Story Source:

The above story is based on materials provided by Children's Hospital Boston. Note: Materials may be edited for content and length.


Cite This Page:

Children's Hospital Boston. "When Does A Mole Become A Melanoma?." ScienceDaily. ScienceDaily, 19 February 2005. <www.sciencedaily.com/releases/2005/02/050211090951.htm>.
Children's Hospital Boston. (2005, February 19). When Does A Mole Become A Melanoma?. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2005/02/050211090951.htm
Children's Hospital Boston. "When Does A Mole Become A Melanoma?." ScienceDaily. www.sciencedaily.com/releases/2005/02/050211090951.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
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:
from the past week

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