Detection and Significance of Minimal Residual Disease from Solid Tumor Malignancies in Stem Cell Autografts
I. INTRODUCTION The increasing use of autologous stem cell transplantation (ASCT) as a means of hematopoietic reconstitution following high-dose chemotherapy (HDC) has heightened the concern about tumor contamination of autologous grafts. Post-ASCT relapse may be due to persistence of disease, the infusion of clonogenic tumor cells, or a combination of the two. Although no study to date has demonstrated that infused tumor cells in contaminated ASCT grafts are solely responsible for posttransplant relapse, the presence of gene-marked, infused tumor cells at sites of disease relapse has been documented in three malignancies (1-3). The presence of tumor cells in autologous grafts is also correlated with poor post-ASCT clinical outcome in a variety of solid-tumor malignancies (4-8). Thus, the sensitive and specific identification of minimal residual disease (MRD) in ASCT grafts is of great concern.