Figure 1.

Connection between clonal behaviour and cellular constitution of the tumor. Differences in clonal behavior result in changes of the cellular constitution of colorectal cancer during normal tumor growth and after chemotherapy as well. In the case of unperturbed tumor growth the proportion of the persistent cell clone increases, short-term cells fade away, while the number of resting cells remains unchanged. Transient cells may appear but later they also fade away. After oxaliplatin therapy the number of the highly proliferative (hence chemotherapy sensitive) persistent cells significantly decreases, while the drug resistant resting cell clone contributes to tumor reappearance.