S7. Cancer prevention: Scientific anticipations and clinical hopes

摘要

Tumors arise through a series of genetic changes which include activation of protoocogenes and inactivation of tumor suppressor genes. There are many new technologies to identify rare cells containing genetic mutations in an excess background of normal cells. Theoretically, the identification of a clonal population of cells sharing an early genetic or epigenetic marker for malignant transformation would lead to valuable intermediate endpoints and could diagnose premalignant lesions amenable to chemoprevention. Ideally, these alterations would occur early in the tumor cascade, prior to the development of a clinically significant tumor. High throughput genomic approaches are describing many possible markers that must be precisely placed in histopathologic tumor models and tested in appropriate populations to better define their value. As an epithelial tumour grows, cancer cells are sloughed off the organ epithelium into body fluids such as blood plasma, urine or saliva.