[What are tumor markers, and what is their value?]

For almost each malignant tumour of the different organ systems there is now a suitable marker substance available permitting the surveillance of the diagnosed cancer patient in the posttherapeutic phase. However, in the evaluation of the marker values certain basic rules have to be respected, which include that markers should be used selectively, that only the kinetics of the curve resulting from the single marker measurements is informative and that due to a lack of tumour specificity markers cannot be used for primary diagnosis. For this reason negative serum marker levels will never exclude the presence of a malignant growth.