Molecular markers in cancer diagnosis.

Clonal genetic alterations are a hallmark of human cancer pathogenesis. These genetic alterations may include specific gene mutations that drive the cancer process or phenotypic changes such as microsatellite instability that may be caused by specific genetic events. Identification of clonal cell populations that share a specific genetic alteration is virtually synonymous with the detection of cancer. These clonal cells can be detected among a large population of normal cells from limited clinical samples by DNA amplification techniques. Because of their unprecedented sensitivity and specificity, these approaches offer new hope for the early diagnosis of human cancer.