<qa>  What is the term for a field effect of carcinogenesis?Many malignancies of the female genital tract may arise in more than one location, either synchronously or metachronously, giving rise to the concept of a field effect of carcinogenesis. By collecting tissue from multiple epithelial sites sampled by the physician it is possible to compare the molecular changes seen in preinvasive to those that occur in invasive neoplasia for differential expression profiles of potential markers. If protein markers are identified in cells present in the diseased tissue we can check the patients serum and urine to see if the proteins can be detected. This information will enable us to screen and possibly identify these protein markers in patient serum and urine to correlate with the presence of a premalignant or malignant state. 