PRESENCE OF TUMOR-CELLS IN BONE-MARROW BUT NOT IN BLOOD IS ASSOCIATEDWITH ADVERSE PROGNOSIS IN PATIENTS WITH EWINGS TUMOR

Purpose: Gene fusions that result from the chromosome translocations o bserved in Ewing's tumor (ET) provide tumor-specific markers that can be used to detect the presence of tumor cells in peripheral blood (PB) , bone marrow (BM), and stem cell collection (SCC), These markers were used to evaluate, at diagnosis, a series of 67 ET patients. Patients and Methods: RNA was extracted from nucleated cells from ph and BM and a nested reverse- transcriptase polymerase chain reaction (RT-PCR) wa s performed to search for EWS-FLI-1 or MIS-ERG fusion transcripts that resulted from the t(11;22) or t(21;22) tanslocations, respectively. R esults: At diagnosis, 16 of 62 (26%) patients had circulating tumor ce lls. This was not correlated with any clinical parameter. In contrast, Ewing's cells were detected by RT-PCR in BM in 14 of 43 (33%) patient s and were associated with the presence of clinically detectable metas tases and ct statistically significant unfavorable outcome in univaria te analysis. There was no correlation between the RT-PCR results in PB and in BM. Conclusion: These results suggested that the monitoring of BM but not of PB by RT-PCR might constitute an important criterion fo r the staging, at diagnosis, of patients with ET. Further studies shou ld appreciate the relationship or independence of this marker toward o ther classical prognostic factors in ET, particularly to the presence of clinically detectable metastases. (C) 1998 by American Society of C linical Oncology.