New Threat Identified in Liver Cancer Development

Researchers in Paris recently identified the role a previously unsuspected virus plays in the development of a rare type of liver cancer. The virus was previously not thought to be harmful to humans, however, now scientists realize the potential threat the virus poses to the liver, especially in patients with hepatitis C virus (HCV).

There are over 8,000 new cases of liver cancer reported each year with men as the main target of the disease. Among the different types of liver cancer, hepatocellular carcinoma usually occurs in a liver that has already been damaged by illnesses such as alcoholism, obesity, hepatitis B and HCV. The latter can cause irreversible lesions, leading to cirrhosis.

Patients with cirrhosis go through multiple tests to detect liver cancer, however, in 5 percent of liver cancer cases, the patient had no prior diagnosis of cirrhosis. In patients with this cancerous anomaly, it remains a mystery to scientists as to what causes the cancer to grow in the first place.

In a recent study, the genome of tumor cells in 11 patients were evaluated. In these patients, the scientists observed the insertion of a viral DNA segment from adeno-associated virus type 2, known as AAV2.

The virus was previously thought to be harmless to humans until now. In order to confirm the involvement of the virus in the development of liver cancer, scientists compared tumor tissues with normal tissues.

Findings from the study indicate that the integration of viral DNA was found more often in tumor cells than in healthy cells in the 11 patients observed. Of these 11 patients, 8 had no diagnosis of cirrhosis and 6 presented no known risk factors for liver cancer.

The scientists also found that in the malignant cells, the virus targets genes that are crucial to cell proliferation while inserting its DNA into the genome of the patients’ cells. The presence of AAV2, therefore, is positively associated with the over-expression of these genes which, according to the researchers, may initiate tumor growth.

“AAV2 is often used as a vector in gene therapy. Although the insertion of its DNA into tumor promoting genes is rare, and probably a chance event, precautions must be taken regarding the use of this virus,” the authors of the study explained.

As the findings of this study are revealed to the public, more scientists realize the threat posed to patients by the AAV2 virus and its correlation to the development of liver cancer. Now that scientists understand this process better, they can work on drugs that target the virus to prevent liver cancer from developing in patients.