Maria Ilaria Del Principe

Toward Optimization of Postremission Therapy for Residual Disease–Positive Patients With Acute Myeloid Leukemia

PURPOSE Despite the identification of several baseline prognostic indicators, the outcome of patients with acute myeloid leukemia (AML) is generally heterogeneous. The effects of autologous (AuSCT) or allogeneic stem-cell transplantation (SCT) are still under evaluation. Minimal residual disease (MRD) states may be essential for assigning patients to therapy-dependent risk categories. PATIENTS AND METHODS By multiparametric flow cytometry, we assessed the levels of MRD in 142 patients with AML who achieved complete remission after intensive chemotherapy. RESULTS A level of 3.5 x 10(-4) residual leukemia cells (RLCs) after consolidation therapy was established to identify MRD-negative and MRD-positive cases, with 5-year relapse-free survival (RFS) rates of 60% and 16%, respectively (P < .0001) and overall survival (OS) rates of 62% and 23%, respectively (P = .0001). Of patients (n = 77) who underwent a transplantation procedure (56 AuSCT and 21 SCT procedures); 42 patients (55%) were MRD positive (28 patients who underwent AuSCT and 14 patients who underwent SCT) and 35 patients (45%) were MRD negative (28 patients who underwent AuSCT and seven who underwent SCT). MRD-negative patients had a favorable prognosis, with only eight (22%) of 35 patients experiencing relapse, whereas 29 (69%) of 42 MRD-positive patients experienced relapse (P < .0001). In this high-risk group of 42 patients, we observed that 23 (82%) of 28 of those who underwent AuSCT experienced relapse, whereas six (43%) of 14 who underwent SCT experienced relapse (P = .014). Patients who underwent SCT also had a higher likelihood of RFS (47% v 14%). CONCLUSION A threshold of 3.5 x 10(-4) RLCs postconsolidation is critical for predicting disease outcome. MRD-negative patients have a good outcome regardless of the type of transplant they receive. In the MRD-positive group, AuSCT does not improve prognosis and SCT represents the primary option.

Molecular and clinical features of chronic lymphocytic leukaemia with stereotyped B cell receptors: Results from an Italian multicentre study

A fraction of chronic lymphocytic leukaemia (CLL) cases carry highly homologous B‐cell receptors (BCR), i.e. characterized by non‐random combinations of immunoglobulin heavy‐chain variable (IGHV) genes and heavy‐chain complementarity determining region‐3 (HCDR3), often associated with a restricted selection of IGVK/L light chains. Such ‘stereotyped’ BCR occur more frequently in CLL with unmutated (UM) than mutated (M) IGHV genes. We analysed 1426 IG rearrangements (from 1398 CLL cases) by a clustering driven by HCDR3 similarities. Molecular findings were correlated to time‐to‐treatment (TTT) and presence of known prognosticators. Sixty‐nine clusters (319 IG‐rearrangements, 22·4%) with stereotyped BCR were identified. Among 30 confirmed clusters (≥3 IG‐rearrangements/cluster), we found 14 novel clusters, of which 11 had M IG rearrangements (M clusters) and predominantly (8/11) used IGHV3 subgroup genes. Recurrent cluster‐biased amino acid changes were found throughout IGHV sequences of these ‘M clusters’. Regarding clinical outcome: (i) UM CLL from the IGHV1‐2/1‐3/1‐18/1‐46/7‐4‐1/IGKV1‐39 cluster had poorer prognosis than UM/M cases, or UM cases using the same IGHV genes but not in clusters; (ii) M CLL from the IGHV3‐21/IGLV3‐21 cluster had TTT similar to UM CLL, and shorter than M CLL expressing IGHV3‐21 but not in cluster. Altogether, our analysis identified additional molecular and clinical features for CLL expressing stereotyped BCR.

Consolidation and maintenance immunotherapy with rituximab improve clinical outcome in patients with B-cell chronic lymphocytic leukemia†

Rituximab in sequential combination with fludarabine (Flu) allowed patients with B‐cell chronic lymphocytic leukemia (B‐CLL) to achieve higher remission rates and longer response duration. Based on their recent experience in indolent non‐Hodgkin lymphomas, in this study, the authors attempted to demonstrate whether consolidation/maintenance therapy with rituximab could prolong the response duration in this patient population.

Cytogenetic and molecular diagnostic characterization combined to postconsolidation minimal residual disease assessment by flow cytometry improves risk stratification in adult acute myeloid leukemia

A total of 143 adult acute myeloid leukemia (AML) patients with available karyotype (K) and FLT3 gene mutational status were assessed for minimal residual disease (MRD) by flow cytometry. Twenty-two (16%) patients had favorable, 115 (80%) intermediate, and 6 (4%) poor risk K; 19 of 129 (15%) carried FLT3-ITD mutation. Considering postconsolidation MRD status, patients with good/intermediate-risk K who were MRD(-) had 4-year relapse-free survival (RFS) of 70% and 63%, and overall survival (OS) of 84% and 67%, respectively. Patients with good- and intermediate-risk K who were MRD(+) had 4-year RFS of 15% and 17%, and OS of 38% and 23%, respectively (P < .001 for all comparisons). FLT3 wild-type patients achieving an MRD(-) status, had a better outcome than those who remained MRD(+) (4-year RFS, 54% vs 17% P < .001; OS, 60% vs 23%, P = .002). Such an approach redefined cytogenetic/genetic categories in 2 groups: (1) low-risk, including good/intermediate K-MRD(-) with 4-year RFS and OS of 58% and 73%, respectively; and (2) high risk, including poor-risk K, FLT3-ITD mutated cases, good/intermediate K-MRD(+) categories, with RFS and OS of 22% and 17%, respectively (P < .001 for all comparisons). In AML, the integrated evaluation of baseline prognosticators and MRD improves risk-assessment and optimizes postremission therapy.

The addition of rituximab to fludarabine improves clinical outcome in untreated patients with ZAP-70-negative chronic lymphocytic leukemia†

Clinical trials of monoclonal antibodies in combination with chemotherapy have reported previously unattained response rates in patients with B‐cell chronic lymphocytic leukemia (B‐CLL); however, the analysis of ZAP‐70 protein and/or CD38 may explain better the discordant outcomes independent of treatment.

A scoring system based on the expression of six surface molecules allows the identification of three prognostic risk groups in B‐cell chronic lymphocytic leukemia

We have previously identified 12 surface antigens whose differential expression represented the signature of B‐cell chronic lymphocytic leukemia (B‐CLL) subsets with different prognosis. In the present study, expression data for these antigens, as determined in 137 B‐CLL cases, all with survivals, were utilized to devise a comprehensive immunophenotypic scoring system of prognostic relevance for B‐CLL patients. In particular, univariate z score was employed to identify the markers with greater prognostic impact, while maximally selected log‐rank statistics were chosen to define the optimal cut‐off points capable to split patients into two groups with different survivals. A weighted immunophenotypic scoring system was developed by integrating results from these analyses. Six antigens were selected: three positive prognosticators (CD62L, CD54, CD49c) and three negative prognosticators (CD49d, CD38, CD79b), with cut‐off values ranging from 30% to 50% of positive cells. By weighing the expression of each marker according to its statistical power, a complete scoring system, with point values comprised between 0 (complete absence of phenotypic conditions associated with good prognosis) and 9 (all the phenotypic conditions associated with good prognosis fulfilled), allowed to split the whole set of B‐CLL patients, into three distinctive prognostic groups (P = 4.78 × 10−11) with high‐ (score 0–3), intermediate‐ (score 4–6), and low‐ (score 7–9) risk of death. The three risk groups showed different distribution of cases as for Rais stages, IgVH mutations, and ZAP‐70 expression. The proposed immunophenotypic scoring system may be an additional useful tool in routine diagnostic/prognostic procedures for B‐CLL. J. Cell. Physiol. 207: 354–363, 2006.

ZAP‐70 expression in B‐cell chronic lymphocytic leukemia: Evaluation by external (isotypic) or internal (T/NK cells) controls and correlation with IgVH mutations

Expression of T cell specific zeta‐associated protein 70 (ZAP‐70) by B‐cell chronic lymphocytic leukemia (B‐CLL) cells, as investigated by flow cytometry, has both prognostic relevance and predictive power as surrogate for immunoglobulin heavy chain variable region (IgVH) mutations, although a standardization of the cytometric protocol is still lacking.

Expression of Mutated IGHV3-23 Genes in Chronic Lymphocytic Leukemia Identifies a Disease Subset with Peculiar Clinical and Biological Features

Purpose: B-cell chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease whose outcome can be foreseen by investigating the mutational status of immunoglobulin heavy chain variable (IGHV) genes. Moreover, a different prognosis was reported for CLL expressing specific IGHV genes in the context or not of stereotyped B-cell receptors. Here we investigated novel associations between usage of specific IGHV genes and clinical features in CLL. Experimental Design: Among 1,426 CLL-specific IG-rearrangements, stereotyped B-cell receptor clusters never utilized the IGHV3-23 gene. Given this notion, this study was aimed at characterizing the IGHV3-23 gene in CLL, and identifying the properties of IGHV3-23–expressing CLL. Results: IGHV3-23 was the second most frequently used (134 of 1,426) and usually mutated (M; 109 of 134) IGHV gene in our CLL series. In the vast majority of M IGHV3-23 sequences, the configuration of the 13 amino acids involved in superantigen recognition was consistent with superantigen binding. Clinically, M IGHV3-23 CLL had shorter time-to-treatment than other M non–IGHV3-23 CLL, and multivariate analyses selected IGHV3-23 gene usage, Rai staging, and chromosomal abnormalities as independent prognosticators for M CLL. Compared with M non–IGHV3-23 CLL, the gene expression profile of M IGHV3-23 CLL was deprived in genes, including the growth/tumor suppressor genes PDCD4, TIA1, and RASSF5, whose downregulation is under control of miR-15a and miR-16-1. Accordingly, relatively higher levels of miR-15a and miR-16-1 were found in M IGHV3-23 compared with M non–IGHV3-23 CLL. Conclusions: Altogether, expression of the IGHV3-23 gene characterizes a CLL subset with distinct clinical and biological features. Clin Cancer Res; 16(2); 620–8

Signature of B‐CLL with different prognosis by Shrunken centroids of surface antigen expression profiling

With the aim of identifying the immunophenotypic profile of B‐cell chronic lymphocytic leukemia (B‐CLL) subsets with different prognosis, we investigated by flow cytometry the expression of 36 surface antigens in 123 cases, all with survivals. By analyzing results with unsupervised (hierarchical and K‐means clustering) algorithms, three distinct immunophenotypic groups (I, II, and III) were identified, group I (51/123) with longer survivals, as compared to the group II (36/123) and III (36/123). The immunophenotypic signatures of these groups, as determined by applying the nearest Shrunken centroids method as class predictor, were characterized by the coordinated and differential expression of 12 surface markers, that is, group I: above‐average expression of CD62L, CD54, CD49c, and CD25, below‐average expression of CD38; group II: above‐average expression of CD38, CD49d, CD29, and CD49e; and group III: below‐average expression of the above markers, overexpression of CD23, CD20, SmIg, and CD79b. As opposed to groups II–III, group I B‐CLLs lacked expression of ZAP‐70 and activation‐induced cytidine deaminase in the majority of cases, while more frequently had mutated IgVH genes and IgVH mutations consistent with antigen‐driven selection. Our findings contribute to improve the immunophenotypical identification of disease subsets with different prognosis and suggest a set of surface antigens to be employed as prognosticators in routine diagnostic/prognostic procedures.

Monitoring of minimal residual disease in acute myeloid leukemia

Purpose of review In acute myeloid leukemia, minimal residual disease (MRD) detection is recognized as a critical diagnostic tool to assess the quality of response after induction therapy and to outline postremissional programs based on the individual risk of relapse. The most popular methods to investigate MRD are multiparametric flow cytometry (MPFC) and polymerase chain reaction, since these techniques have proven sensitive and specific enough to allow MRD to be studied serially. In the present review we will focus on the use of MPFC for monitoring of MRD, addressing the main technical and clinical issues. Recent findings Lack of standardization among different laboratories, immunophenotypic stability, identifications of thresholds and time-points during follow-up represent the major subjects of confrontation whose definitive solution might rely on the application of new technologies and dedicated statistical approaches. Summary Studies of MRD should provide us the opportunity to generate comprehensive prognostic algorithms which take into account conventional parameters, such as cytogenetic and genetic profile, and those strictly inherent to the quality of response, such as determination of residual leukemia. This will greatly enhance development of personalized therapeutic approaches, avoiding the situation of under or over drug exposure.