399 BONE MARROW STEM CELLS EXPRESSING CD34 ARE MOBILIZED IN DIFFERENT HISTOTYPES OF LIVER CANCER

POSTERS carcinomas (10), germ cell tumors (6) and in undifferentiated childhood tumors: Wilms tumor (5), neuroblastoma (7), meduloblastoma (5), kidney rhabdoid tumor (1).Results: All the hepatoblastomas were positive for DLK.The staining was mostly focal covering 5-30% of the areas of tumors, the surrounding liver tissue remained negative.The reaction was present always in the epithelial component of the tumors but there was no preferential staining over the fetal or embryonic parts.The staining pattern was membranous and cytoplasmic.The differentiating cells of two ganglioneuroblastomas stained positively, no reaction was observed in any other tumors.Conclusions: DLK immunostaining seems to be a highly sensitive and specific marker for hepatoblastomas.If this primary observation can be confirmed DLK can be used as an immunohistochemical marker for hepatoblastomas.The biological function of DLK in hepatoblastomas requires further studies.However since DLK is a membrane receptor it can be considered a molecular target for therapeutical approaches.