Some Tonsil Cancer Patients May Avoid Chemotherapy

Clinical researchers at Princess Margaret Hospital (PMH) have confirmed that patients with oropharyngeal squamous cell cancer (“tonsil cancer”) harbour a common type of human papilloma virus (HPV16), but also that such cancers are very sensitive to radiation. For some patients, this may mean successful treatment with radiation alone and avoiding the side effects of chemotherapy.

“This represents the power of personalized medicine. By using a relatively simple molecular test to evaluate the tumour, we can customize the treatment plan, produce an excellent outcome, and maintain the patient’s quality of life,” says principal investigator Dr. Fei-Fei Liu, PMH radiation oncologist, Head of the Division of Applied Molecular Oncology, Ontario Cancer Institute, and Dr. Mariano Elia Chair in Head & Neck Cancer Research, University Health Network.

The findings were published on November 2 in the Journal of Clinical Oncology (JCO 231670). Read more

HPV Vaccine Clears Viral Infection And May Reduce Cancerous Lesions

A new vaccine designed to stimulate an immune response against a cancer-causing human papillomavirus (HPV-16) can eliminate chronic infection by the virus and may cause regression of precancerous genital lesions in women who receive the vaccine.

According to a report published in the November 5 issue of the New England Journal of Medicine (2009;361:1838-47), the vaccine successfully induced HPV-specific immune responses in 100% of patients with advanced vulvar intraepithelial neoplasia (VIN3), a life-threatening disease that in the majority of cases results from HPV infection and for which there is as yet no satisfactory standard therapy.

Among the women who participated in the study, the majority (79%) experienced measurable regression of their VIN3 lesions within 1 year of vaccination. Nine of the women (47%) experienced complete disappearance of lesions and were still symptom-free two years following vaccination. The virus was undetectable in four of five women whose disease had regressed completely after the first year.

According to researchers who conducted the phase II study at the Leiden University Medical Center in Leiden, The Netherlands, spontaneous regression of HPV-16 positive VIN3 lesions is very rare, occurring in less than 1.5% of patients. The induction of HPV-specific T-cell immune responses following vaccination, and the researchers’ observation that stronger vaccine-induced immune responses correlated with better clinical outcome indicate that the vaccine is the most likely cause of the high response rate among the patients treated in the study. Read more

Targeting “Normal” Cells In Tumors Slows Growth

Targeting the normal cells that surround cancer cells within and around a tumor is a strategy that could greatly increase the effectiveness of traditional anti-cancer treatments, say researchers at The Wistar Institute.

In the Journal of Clinical Investigation published online November 16, they demonstrate the critical role for fibroblast activation protein (FAP), expressed by one type of these so-called “stromal” cells, in promoting tumor growth in mice. Genetically deleting or therapeutically targeting FAP significantly reduced the rate of tumor growth in mice by interrupting or blocking important signaling pathways and biological processes required for tumor growth, the Wistar team found.

“It’s like taking away the soil from a seed that wants to grow,” says senior author Ellen Puré, Ph.D., a professor in the Molecular and Cellular Oncogenesis Program at Wistar. “These results provide a proof-of-principle that targeting and modifying a tumor’s microenvironment may be an effective approach to treating solid tumors.”

Tumors are a complex mix of neoplastic cancer cells and normal cells – inflammatory and immune cells, endothelial cells, fibroblasts, pericytes, and others, collectively known as stromal cells. In addition, a web-like extracellular matrix is created by the stromal cells, and its structure is important for supporting and nurturing tumor growth through molecular signaling pathways. Read more

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