( To most the mere mention of the word ...)Turning viruses into allies against cancer

Through genetic engineering, viruses are being re-programmed to take advantage of their natural abilities to infiltrate, commandeer, replicate and destroy, but only in tumor cells and not surrounding healthy tissue.

Several of these "oncolytic" (cancer-killing) viruses are in varying stages of development, including modifications of the virus that causes measles and another, the herpes simplex virus, responsible for those lip blisters known as cold sores.

In studies presented this week at the 96th meeting of the American Association for Cancer Research (AACR), researchers describe their latest studies with their engineered versions of these viruses.

Cold Sore Virus Modified to Halt Growth and Spread of a Variety of Tumors: Abstract 5292

A modified herpes simplex virus, built with a potent immune stimulant to thwart the spread of cancer cells, is being tested in patients with a variety of tumor types, including melanoma, breast, head and neck, and colorectal cancer.

In early clinical studies, the engineered virus -- developed by Biovex Ltd. under the trade name OncoVEX -- showed promise of causing necrosis (death) of tumors cells in most patients.

"Tumor necrosis was evidenced clinically and/or by histology in biopsies taken about two weeks after the final dose in a number of patients," said Jennifer Hu, M.B.B.S., a clinical research fellow at Hammersmith Hospital (Imperial College) in London, who conducted much of the study. "In some cases necrosis was considerable."

Like other oncolytic viruses, the modified herpes simplex virus used in these studies was engineered to attack tumors cells without harming surrounding healthy tissue. This virus also was further altered to
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Source:American Association for Cancer Research