Navigation Links
Newly discovered virus linked to deadly skin cancer

PITTSBURGH, Jan. 17 A new strategy to hunt for human viruses described in this weeks issue of the journal Science by the husband-and-wife team who found the cause of Kaposis sarcoma has revealed a previously unknown virus strongly associated with another rare but deadly skin cancer called Merkel cell carcinoma. In the paper, University of Pittsburgh Cancer Institute (UPCI) researchers, Huichen Feng, Ph.D., Masahiro Shuda, Ph.D., Yuan Chang, M.D., and Patrick Moore, M.D., M.P.H., explain a nearly decade-long effort to harness the sequencing technology to identify the virus, which they call Merkel cell polyomavirus (MCV). While the research team emphasizes that their work does not prove MCV to be the cause of Merkel cell carcinoma, if the findings are confirmed, they may lead to new cancer treatment and prevention options.

This is the first polyomavirus to be strongly associated with a particular type of human tumor, said Dr. Moore, professor of microbiology and molecular genetics at the University of Pittsburgh School of Medicine and leader of the molecular virology program at UPCI. Although polyomaviruses have been studied in relation to cancer development for years, the weight of scientific evidence had been leaning toward the view that these viruses do not cause human cancers.

Polyomaviruses are a group of viruses that have been shown to cause cancers in animals for more than 50 years. But Dr. Moore noted that additional research is needed to determine what role, if any, MCV plays in human cancer development.

A rare but extremely aggressive cancer that spreads rapidly into other tissues and organs, Merkel cell carcinoma (MCC) develops from specialized nerve cells that respond to touch or pressure. The incidence of MCC has tripled over the past 20 years to about 1,500 cases a year, especially among people whose immune systems are compromised by AIDS or transplant-related immunosuppressant drugs. About half of patients with advanced MCC live nine months or less, and some two-thirds of MCC patients die within five years.

If these findings are confirmed, we can look at how this new virus contributes to a very bad cancer with high mortality, and, just as importantly, use it as a model to understand how cancers occur and the cell pathways that are targeted, added Dr. Moore. Information that we gain could possibly lead to a blood test or vaccine that improves disease management and aids in prevention.

For example, vaccines are now available against human papillomavirus (HPV) to prevent cervical cancer, noted Dr. Chang, professor of pathology. MCV is another model that may increase our understanding of how cancers arise, with possibly important implications for non-viral cancers like prostate or breast cancer.

MCV has additional similarities to HPV since both viruses integrate into the tumor cell genome but not the genome of healthy cells. This integration destroys the viruss ability to replicate normally and may be the first critical step in MCC development.

The Pittsburgh team analyzed nearly 400,000 messenger RNA genetic sequences from four samples of MCC tumor tissue using a technique refined in their lab called digital transcriptome subtraction (DTS). Comparing the sequences expressed by the tumor genome to gene sequences mapped by the Human Genome Project, the researchers systematically subtracted known human sequences, leaving a group of genetic transcripts that might be from a foreign organism.

One sequence was similar to but distinct from all known viruses. The team went on to show that this sequence belonged to a new polyomavirus present in eight of 10 (80 percent) Merkel cell tumors they tested but only five of 59 (8 percent) control tissues from various body sites and four of 25 (16 percent) control skin tissues.

Although MCV is most commonly found in Merkel cell tumors, it also can be found in healthy people. The most important distinguishing feature is that MCV integrates into tumor cells in what is known as a monoclonal pattern, indicating that it infects the cell before the cell becomes cancerous. Tests on six of the eight MCV-positive tumors confirmed that viral DNA was integrated within the tumor genome in this monoclonal pattern, suggesting that infection with MCV could be a trigger for tumor formation. The Pittsburgh team subsequently has confirmed these results with additional tumor specimens.

Clues from elsewhere in the biomedical literature point to the existence of MCV, which has a genetic structure that is closely related to an African green monkey virus found in Germany in the 1970s. Researchers have found antibody evidence from blood tests that indicates some 15 percent to 25 percent of adults are infected with the still undiscovered human relative of this monkey virus. If MCV turns out to be this long-sought infection, then more than 1 billion people worldwide could already be infected.

But again, look to the example of HPV, said Dr. Moore. Although up to 50 percent of sexually active young women are infected with HPV, a small proportion may actually get cervical cancer.

Even if MCV is proven to play a role in MCC, Dr. Chang also cautioned that the virus is likely to be just a part of a much larger picture.

Now we need to find out how it works, she said. Once the virus integrates, it could express an oncoprotein, or it could knock out a gene that suppresses tumor growth. Either way, the results are bound to be interesting.

This is the second tumor-associated virus discovered by Drs. Moore and Chang, a husband-and-wife research team who also discovered Kaposis sarcoma-associated herpesvirus (KSHV) in 1993. KSHV, which causes Kaposis sarcoma, is the most common malignancy in AIDS patients and the most common cancer in Africa. To find KSHV, Drs. Moore and Chang used a different method to physically subtract human genetic sequences from Kaposis sarcoma tumors, leaving fragments of viral DNA.

Viruses, and some bacteria and parasites, are estimated to cause at least 20 percent of cancers worldwide. Over the past 40 years, few cancer-causing viruses have been confirmed in humans, including KSHV. Most of these viruses express cancer-causing proteins, called oncoproteins, in infected cells. Polyomaviruses, including MCV, possess an oncoprotein that has been shown to cause cancer after infection in animals. If MCV is confirmed to play a role in human cancer, it will be the eighth human tumor virus discovered.


Contact: Michele Baum
University of Pittsburgh Schools of the Health Sciences

Related medicine news :

1. Antibody Engineering Company f-star Appoints Three Pioneers in Antibody Engineering and Development to its Newly Established Scientific Advisory Board
2. New therapeutic options for newly diagnosed multiple myeloma patients
3. Thalidomide Added to Standard Therapy Prolongs Overall Survival in Newly Diagnosed Multiple Myeloma Patients Over Age 75
4. Newly HIV-Infected Gay Men Select Other Infected Partners
5. Striking shift seen among newly HIV-infected men regarding partners
6. Hidden Costs Plague Owners Occupying Newly Constructed Buildings; New Program Can Help Avoid Major Issues
7. Corrected & Replaced - Natural Nutrition Expands Revenue Capabilities with Newly Installed State of the Art Nutrition Bar Line
8. Natural Nutrition Expands Revenue Capabilities with Newly Installed State of the Art Nutrition Bar Line
9. Newly Published Study in Leading Medical Journal Further Confirms the Brava Systems Non-Surgical Breast Enhancement Effectiveness
10. Higher death rates in kidney patients with newly recognized disease
11. Common abdominal pain may be due to a potentially treatable newly recognized inflammatory reaction
Post Your Comments:
(Date:11/30/2015)... ... , ... While powdered supplements and drinks can reduce food preparation time, locating ... Va., has found an easy to keep track of the scoop. , He developed ... in a canister or other container handy and readily accessible. As such, it prevents ...
(Date:11/30/2015)... (PRWEB) , ... November 30, 2015 , ... ... just publishing magazines and websites specializing in independent living, assisted living and all ... paramount, and Alzheimer’s awareness and research remains a top priority. ...
(Date:11/30/2015)... Morton Grove, IL (PRWEB) , ... November 30, 2015 , ... ... milestone for an emerging pharmaceutical company. Because it is so important to this key ... titled “Success Factors in your IND Filing” on December 4th at 11am EST. , ...
(Date:11/30/2015)... ... November 30, 2015 , ... ... of critical importance to the medical schools of the future. To reach an ... suite at the 2015 ChangeMedEd conference in Chicago, organized by the American Medical ...
(Date:11/30/2015)... ... November 30, 2015 , ... ... are pleased to announce their strategic partnership at the Radiological Society of ... Service, Inc., and Winscribe, global providers of cutting-edge dictation and speech-enabled documentation ...
Breaking Medicine News(10 mins):
(Date:11/30/2015)... , Nov. 30, 2015  Precision Image ... services, is pleased to announce a dramatic expansion ... imaging services. Building on its ISO-9001:2008 certification for ... implemented comprehensive Core Lab protocols and procedures. This ... of research activities.  Their Core Lab services include ...
(Date:11/30/2015)... Sectra (STO: SECT B) ... into a multi-year agreement to provide Breast Imaging PACS ... Breast Care to increase collaboration with sub-specialists around the ... --> Sectra (STO: SECT B) ... into a multi-year agreement to provide Breast Imaging PACS ...
(Date:11/29/2015)... Nov. 29, 2015 CIVCO Medical Solutions ... at the Radiological Society of North ... Chicago November 29 – December 4, ... to offer customers unrivaled versatility, enhanced user experience ... --> ...
Breaking Medicine Technology: