[Metastatic enhancement: biological mechanisms and therapeutic implications]

In experimental models chemotherapeutic agents enhance spontaneous metastases. Vascular toxicity and myelotoxicity may account for this phenomenon. However, drugs may act directly on tumor cells. Clonogenic resistant cells are involved in the metastatic process facilitation. Fundamental biological mechanisms are evoked to explain these observations. Mutagenicity and its consequences on gene expression or regulation are another hypothesis. Clinical investigations are necessary to confirm the results obtained from animal models.