Tumor load in patients with follicular lymphoma post stem cell transplantation may correlate with clinical course

Abstract

Summary:The purpose of this study was to evaluate if the tumor load, as determined by a real-time quantitative PCR (RQ-PCR) assay, correlated with the clinical course of follicular lymphoma patients after stem cell transplantation (SCT). Cryopreserved bone marrow and/or peripheral blood samples obtained at different time intervals after SCT from 11 patients (seven allogeneic, T-cell depleted/four autologous) were tested for tumor load, as defined by t(14;18) positive cells/total cells, using RQ-PCR. None of the six patients who remained in remission had samples with a tumor load 40.01% after SCT, although fluctuating tumor loads of p0.01% were observed in three of these patients. In contrast, four of the five patients (three allogeneic/two autologous) with relapsed/progressive disease had increasing tumor loads of 40.01% after SCT (0/6 vs 4/5, Po0.02, Fisher's exact). Our results suggest that RQ-PCR measurable tumor load 40.01% after SCT may correlate with relapsed/progressive disease. Prospective studies with greater numbers of cases are indicated to better determine the critical tumor load that predicts poor outcome after SCT with RQ-PCR.

Commercial LightCycler®-based quantitative real-time PCR compared to nested PCR for monitoring of Bcl-2/IgH rearrangement in patients with follicular lymphoma

“…Quantitative PCR may offer additional benefits as it may (a) allow for the identification of patients with an increase in MRD after therapy, being at an increased risk of relapse [33][34][35] and (b) stratify patients according to the initial tumour load in BM, thereby predicting response to therapy and long-term outcome [36]. Our results suggest that the relatively low sensitivity of the LigthCycler assay may be disadvantageous for the prediction of early relapse after therapy.…”

Concurrent presence of both patient and donor t(14;18) in a follicular lymphoma patient after undergoing allogeneic BMT: implications for minimal residual disease detection post-transplant

“…Our group and others have recently shown that monitoring levels of minimal residual disease (MRD), by using real-time quantitative PCR (RQ-PCR) for t(14;18) + lymphocytes, may predict relapse in FL patients post-BMT before overt clinical relapse. 4,5 In these studies, clinical relapse is usually preceded by a gradual increase in the quantity of t(14;18) + neoplastic lymphocytes post-BMT, while long-term clinical remission is associated with negative or stable low levels of (14;18) + lymphocytes. Distinguishing between patient and donor origin of t(14;18) + clones in these studies is confounded by the observation that approximately 23-50% of normal healthy individuals have detectable t(14;18) positive cells in their peripheral blood (PB).…”

“…5 The PCR products were then subjected to agarose gel electrophoresis to visualize their size (Figure 1). Amplification of t(14;18) at the MBR was observed using DNA isolated from donor PB (Figure 1 'D').…”

The implication of follicular lymphoma patients receiving allogeneic stem cell transplantation from donors carrying t(14;18)-positive cells

“…This RQ-PCR assay was developed to detect and quantitate cells carrying t(14;18) (BCL-2/IGH fusion) at the major breakpoint region (MBR) and reported in detail previously. 16 The RQ-PCR assay showed the sensitivity of detecting a single cell carrying t (14;18) in the background of 40 000 normal cells (ie a tumor load of 0.0025%). The linear measuring range of the standard curve of quantitation of the assay was between tumor loads of 0.01 to 10%.…”

“…[12][13][14][15] We have recently reported that monitoring the tumor load of t(14;18) cells by real-time quantitative PCR (RQ-PCR) may predict the outcome of FL patients after allo-SCT. 16 Patients with tumor loads of greater than one t(14;18) cell per 10K total cells post transplantation have a higher risk of clinical relapse than those without. The monitoring of minimal residual disease (MRD) by RQ-PCR allows for the development of strategies, such as donor lymphocyte infusions to be employed at a stage of molecular relapse in patients whose RQ-PCR results suggest a high likelihood of subsequent clinical relapse.…”