Minimal residual disease at the time of peripheral blood stem cell harvestin patients with advanced neuroblastoma

Background. Despite treatment with high-dose myeloblative chemotherapy and peripheral blood stem cell (PBSC) rescue, a high proportion of children wit h neuroblastoma relapse and die. Re-infusion of PBSC contaminated with tumo ur at the time of autologous transplantation may play a significant role in this relapse. In this study the frequency of tumour contamination in PB fr om children with neuroblastoma has been investigated. Procedure. Minimal re sidual disease was measured using RT-PCR for tyrosine hydroxylase (TH) mRNA in PBSCs from patients with advanced neuroblastoma. PBSCs from 18 patients in complete clinical remission were studied. Results. Studies in other can cers have suggested minimal contamination of PBSCs with tumour cells; TH mR NA was detected by RT-PCR in 50% (9/18) of PBSC harvests. Seventy-seven per cent (7/9) of patients with TH mRNA in PBSC died of disease compared to 44% (4/9) who were TH mRNA-negative. Conclusions. Therefore, the presence of T H mRNA in PBSCs appeared to be associated with an unfavourable outcome, alt hough this was not statistically significant. In summary, RT-PCR for TH mRN A is a sensitive method for the identification of tumour cells in PBSC harv est. The presence of TH mRNA in PBSC harvest may reflect disease status and be associated with an unfavourable outcome, although long-term clinical ou tcome studies in a larger patient cohort are required. Med. Pediatr. Oncol. 36:213-219, 2001. (C) 2001 Wiley-Liss, Inc.