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Here, we describe the immunoglobulin and T cell receptor (Ig/TCR) molecular rearrangements identified as a leukemic clone hallmark for minimal residual disease assessment in relation to TP53 mutational status in 171 Ph-negative Acute Lymphoblastic Leukemia (ALL) adult patients at diagnosis. The presence of a TP53 alterations, which represents a marker of poor prognosis, was strictly correlated with an immature DH/JH rearrangement of the immunoglobulin receptor ( p < 0.0001). Furthermore, TP53 -mutated patients were classified as pro-B ALL more frequently than their wild-type counterpart (46% vs. 25%, p = 0.05). Although the reasons for the co-presence of immature Ig rearrangements and TP53 mutation need to be clarified, this can suggest that the alteration in TP53 is acquired at an early stage of B-cell maturation or even at the level of pre-leukemic transformation.

Acute lymphoblastic leukemia (ALL) is curable in about 40-50% of adult patients, however this is subject to ample variations owing to several host- and disease-related prognostic characteristics. Currently, the study of minimal residual disease (MRD) following induction and early consolidation therapy stands out as the most sensitive individual prognostic marker to define the risk of relapse following the achievement of remission, and ultimately that of treatment failure or success. Because substantial therapeutic advancement is now being achieved using intensified pediatric-type regimens, MRD analysis is especially useful to orientate stem cell transplantation choices. These strategic innovations are progressively leading to greater than 50% cure rates.

The therapeutic role of mediastinal radiotherapy and stem cell transplantation (SCT) in lymphoblastic lymphoma (LL) remains controversial. In a risk-oriented design, we adopted a flexible treatment program in which (1) patients with persistent mediastinal abnormality, evaluated by post-induction computed chest tomography, received mediastinal irradiation; and (2) those with persistence of minimal residual disease (MRD), evaluated by MRD analysis of the bone marrow, underwent SCT. Twenty-eight out of 30 patients (T-lineage, n = 24; B-lineage, n = 6) achieved a complete response. Of 21 patients with mediastinal mass, 13 (62%) achieved a complete response after chemotherapy alone, while 6 (28.5%) required additional irradiation. Eleven patients were evaluated for MRD: 6 were negative and 5 positive. On the basis of MRD findings and clinical risk characteristics, 14 patients underwent SCT, 13 received maintenance chemotherapy, and 1 had local radiotherapy. Five patients relapsed. Among the 14 non-irradiated patients with T-LL, the mediastinal recurrence rate was only 7%. After a median follow-up of 3.9 years, 21 patients who responded were alive without recurrence (75%). The projected 5-year survival, disease-free survival, and relapse rate were 72%, 77%, and 18%, respectively. This program induced high remission and survival rates, indicating the feasibility and the benefits potentially associated with a selective, response-oriented policy of mediastinal irradiation and a concurrent MRD-based strategy to assign adult LL patients to SCT.

Clinical risk classification is inaccurate in predicting relapse in adult patients with acute lymphoblastic leukemia, sometimes resulting in patients receiving inappropriate chemotherapy or stem cell transplantation (SCT). We studied minimal residual disease (MRD) as a predictive factor for recurrence and as a decisional tool for postconsolidation maintenance (in MRD(neg)) or SCT (in MRD(pos)). MRD was tested at weeks 10, 16, and 22 using real-time quantitative polymerase chain reaction with 1 or more sensitive probes. Only patients with t(9;22) or t(4;11) were immediately eligible for allogeneic SCT. Of 280 registered patients (236 in remission), 34 underwent an early SCT, 60 suffered from relapse or severe toxicity, and 142 were evaluable for MRD at the end of consolidation. Of these, 58 were MRD(neg), 54 MRD(pos), and 30 were not assessable. Five-year overall survival/disease-free survival rates were 0.75/0.72 in the MRD(neg) group compared with 0.33/0.14 in MRD(pos) (P = .001), regardless of the clinical risk class. MRD was the most significant risk factor for relapse (hazard ratio, 5.22). MRD results at weeks 16 to 22 correlated strongly with the earlier time point (P = .001) using a level of 10(-4) or higher to define persistent disease. MRD analysis during early postremission therapy improves risk definitions and bolsters risk-oriented strategies. ClinicalTrials.gov identifier: NCT00358072.

Background and Objectives: The molecular analysis of minimal residual disease (MRD) may provide information on the risk of recurrence in patients with acute lymphoblastic leukemia (ALL). The aim of this study was to correlate the kinetics of MRD clearance after allogeneic transplantation with the clinical outcome of adults with ALL., Design and Methods: MRD was evaluated by real-time quantitative polymerase chain reaction (RQ-PCR) using probes derived from fusion chimeric genes (BCR/ABL and MLL/AF4) (n=22) or rearrangements of the T-cell receptor or immunoglobulin genes (n=21). Forty-three adult patients with ALL were studied to correlate the kinetics of MRD clearance before and after allogeneic hematopoietic stem cell transplantation., Results: At 36 months, the overall survival of patients who underwent transplantation in hematologic remission (n= 37) was 80% for those who were PCR-negative before transplantation (n= 12) compared to 49% for PCR-positive patients (n= 25)(p=0.17). For the same patients the cumulative incidence of relapse was 0% and 46%, respectively (p=0.027). Moreover, the relapse rate of patients who were PCR-negative at day +100 after transplantation was remarkably low (7%) compared to that among patients who were PCR-positive (80%, p=0.0006)., Interpretation and Conclusions: The kinetics of MRD clearance may help to identify patients at high risk of leukemia relapse after allogeneic stem cell transplantation. Patients not achieving an early molecular remission after transplantation require prompt and appropriate pre-emptive treatments such as infusions of donor lymphocytes or new experimental drugs.