Molecular Diagnostics of Cancer

The first consistent chromosomal abnormality to be described in a tumor cell was the Philadelphia chromosome (1 ), but it was not until the advent of high resolution chromosome banding (2 ,3 ) that the occurrence of other abnormalities in malignant cells could be fully investigated. Since then, much detailed information has been derived concerning the incidence and nature of molecular abnormalities in human malignancies. Some changes seem to be highly correlated with particular malignancies, whereas others are more general in their incidence. An individual malignancy can often have more than one alteration, with secondary changes superimposed on an original primary event. Many chromosomal translocations, in which genetic material is exchanged between chromosomes, have been documented. Other types of chromosomal alterations can include interstitial deletions, monosomy, trisomy, aneuploidy and the appearance of chromosomes so rearranged as to be unrecognizable. At the submicroscopic level, point mutations in several genes have been documented in tumor cells.