Basal-cell carcinoma
Basal-cell cancer is a very common skin cancer. It is much more common in fair-skinned individuals with a family history of basal-cell cancer and increases in incidence closer to the equator or at higher altitude. There are approximately 800,000 new cases yearly in the United States alone. Up to 30% of Caucasians develop basal-cell carcinomas in their lifetime. In Canada, the most common skin cancer is basal-cell carcinoma (as much as one third of all cancer diagnoses), affecting 1 in 7 individuals over a lifetime.
Cancer immunoprevention
Immunoprevention of tumors caused by viruses or other infectious agents aims at preventing or curing infection before the onset of cancer. Effective vaccines are available for use in humans.
Some tumor types in humans and in animals are the consequence of viral infections. In humans the most frequent viral tumors are liver cancer (also called hepatocellular carcinoma), arising in a small proportion of patients with chronic infection by hepatitis B virus (HBV) or hepatitis C virus (HCV), and carcinoma of the uterine cervix (also called cervical cancer), caused by human papilloma virus (HPV). Altogether these two tumors make 10% of all human cancers, affecting almost one million new patients each year worldwide.
The HBV vaccine, now in worldwide use, was shown to reduce the incidence of liver carcinoma. Cancer immunoprevention by the HBV vaccine can be thought of as a beneficial side effect of vaccine developed and used to prevent hepatitis B. This is not the case with HPV vaccines, which were primarily developed for cancer prevention. Clinical trials showed that HPV vaccines can prevent HPV infection and carcinogenesis almost completely; these results led to vaccine approval by regulatory agencies in USA and Europe.