An interdisciplinary approach to populations at high risk of cancer

Investigation and management of patients at high risk of developing cancer

Recent developments in cancer genetics have revealed genes that render individuals susceptible to cancer. These families have a unique set of new problems and benefits that must be thought through for the potential good to be accrued from these discoveries. Individual patients seek early diagnosis and prevention strategies that challenge the limits of current knowledge. Some available methods have not yet been evaluated. There is a need for the evidence to support plans of care, and consistency is required from one centre to the next in the advice given. These familial cancers are often different from the more common sporadic cases, and so traditional treatments need to be tested again in the context of the new genetic knowledge. Three groups of cancers, breast, ovary and colon, have been used to illustrate the issues surrounding these high risk families, their investigation and care. In applying new strategies to these patients, ethical issues arise that are new to the medical world, and must be considered by the lay public. It is up to the medical profession, patients and society to use this knowledge to give benefit to a vulnerable group, and not to give unaffordable hopes and unnecessary anxieties.

p53: functions, mutations and sarcomas

The p53 gene is the most commonly altered gene in a multitude of human cancers. The alterations can be acquired somatically or transmitted through the germ-line. Bone and soft tissue sarcomas are frequently found to have acquired abnormalities in the p53 and mdm-2 genes. In soft tissue sarcoma, the amplification of the mdm-2 gene and the binding of its oncogene product to wild-type p53 protein functionally inactivates normal p53-regulated growth. Inherited mutations of the p53 gene are associated with the rare Li-Fraumeni familial cancer syndrome. Various tumor types arise in these families, with sarcomas of the bone and soft tissues and carcinoma of the breast being the most frequently observed. Transgenic mice with highly expressed mutated p53 have a higher incidence of tumors, including predominantly osteosarcomas and soft tissue sarcomas. In close similarity with the Li-Fraumeni syndrome, homozygously p53-null mice (transgenic mice carrying two non-functional p53 allele) are developmentally normal however they are susceptible to spontaneous tumor formation. This article reviews briefly the structure, function, and dysfunction of the p53 tumor-suppressor gene with particular focus on its role in the development of bone and soft tissue sarcoma.