The presence of neuroblastoma cells in marrow grafts has been linked to the recurrence of the disease post bone marrow transplantation. To avoid this problem, different techniques have been developed to purge tumor cells from the graft. We studied the presence of neuroblasts in bone marrows (BM) of neuroblastoma patients undergoing autologous bone marrow transplantation (ABMT) before and after immunomagnetic purging and compared it to their presence in peripheral blood (PBL). The presence of neuroblasts was also measured in peripheral blood stem cells (PBSC) pheresed after G-CSF stem cell mobilization. We employed the immunofluorencense (IF) method utilizing polylysine-coated dishes or immunocytochemistry (IC) using avidin-biotin peroxidase techniques combined with anti-neuroblastoma monoclonal antibodies. These techniques are capable of identifying one tumor cell in 10 5 mononuclear BM or PBL cells. To further investigate tumor contamination, we tested marrows before and after purging, PBL at the time of marrow collection, and PBSC after G-CSF mobilization by RT-PCR targeting a neuroendocrine gene product (PGP 9.5); this technique is capable of identifying one neuroblastoma cell in 10 7 mononuclear cells. Our data show approximately one log decrease in tumor cell number in BM purged by immunomagnetic purging which was statistically significant (p < 0.0005). Compared to bone marrow, peripheral blood obtained at the time of the purge and PBSC obtained after G-CSF mobilization had a significantly lower contamination as detected by IF or IC (p < 0.01). RT-PCR analysis demonstrated that following purging two thirds of the marrows were still positive for the presence of neuroblasts; significant rates of contamination were observed for PBL and PBSC using RT-PCR. In conclusion, a significant proportion of marrow grafts still contained tumor cells after purging. Peripheral blood stem cell harvests had a lower level of tumor contamination as compared to purged marrow when tested by IF or IC. Both marrow and blood stem cell products had a high contamination rate detected by RT-PCR.
|Original language||English (US)|
|Number of pages||6|
|Journal||Cancer Research Therapy and Control|
|State||Published - 1999|
- Peripheral rule
ASJC Scopus subject areas
- Cancer Research