Micrometastases in pediatric oncology

Metastatic relapse in children with solid tumors is mainly caused by system ic pretreatment dissemination of occult tumor cells. Therefore the initial detection of undetected metastases could have a clinical impact on the prog nosis (i.e. new initial staging) and therapy for children with cancer At la ter stage it is useful to determine the presence and change in the number o f residual malignant cells in order to adjust and/or select adjuvant therap ies and techniques (i.e. autologous bone marrow transplantation, leukaphere sis...), Over the past decade, sensitive immunocytochemical and molecular a ssays have been developped which permit the identification of disseminated cancer cell Actually tumor cell contamination can be detected in bone marro w or in peripheral blood of children with following cancers: neuroblastoma, Ewing tumor, alveolar rhabdomyosarcoma, PNETs. In this review, focus is on the recent technical achievements in the detection of occult cancer cells in bone marrow and in blood and a discussion of their usefulness for clinic al trials.