Mosaicism in tumor cytogenetics

By definition a tumor disease represents a mosaicism with respect to the entire organism but in addition most tumors also show mosaicism within themselves. This status of mosaicism is usually called intratumoral heterogeneity and is an essential factor which is of relevance for diagnostic as well as for therapeutic strategies. To be able to analyze the genetic changes of a tumor it has to be ensured that a sufficient number of tumor cells is analyzed and not only normal tissue. This is achieved in the diagnostic work-up of the different neoplasias with various approaches depending on the diagnostic method used and the type of neoplasia. Methods are used which either enrich the malignant cells stimulating them to targeted proliferation or the method is carried out with sufficient sensitivity to also detect small clones.