Clonality Analysis of Immunoglobulin Gene Rearrangement by Next-Generation Sequencing in Endemic Burkitt Lymphoma Suggests Antigen Drive Activation of BCR as Opposed to Sporadic Burkitt Lymphoma.

OBJECTIVES: Recent studies using next-generation sequencing (NGS) analysis disclosed the importance of the intrinsic activation of the B-cell receptor (BCR) pathway in the pathogenesis of sporadic Burkitt lymphoma (sBL) due to mutations of TCF3/ID3 genes. Since no definitive data are available on the genetic landscape of endemic Burkitt (eBL), we first assessed the mutation frequency of TCF3/ID3 in eBL compared with sBL and subsequently the somatic hypermutation status of the BCR to answer whether an extrinsic activation of BCR signaling could also be demonstrated in Burkitt lymphoma. METHODS: We assessed the mutations of TCF3/ID3 by RNAseq and the BCR status by NGS analysis of the immunoglobulin genes (IGs). RESULTS: We detected mutations of TCF3/ID3 in about 30% of the eBL cases. This rate is significantly lower than that detected in sBL (64%). The NGS analysis of IGs revealed intraclonal diversity, suggesting an active targeted somatic hypermutation process in eBL compared with sBL. CONCLUSIONS: These findings support the view that the antigenic pressure plays a key role in the pathogenetic pathways of eBL, which may be partially distinct from those driving sBL development.

Complete and long-lasting cytologic and molecular remission of FIP1L1-PDGFRA-positive acute eosinophil myeloid leukaemia, treated with low-dose imatinib monotherapy.

Myeloproliferative neoplasms associated with FIP1L1-PDGFR rearrangements represent a rare subset of myeloid and lymphoid malignancies, characterised by the presence of eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1 genes. The fusion product of such genes is a tyrosine kinase oncoprotein sensitive to imatinib, which to date results to be the standard of care for FIP1L1-PDGFRA-positive chronic myeloproliferative disorders with eosinophilia. However, the coexistence of FIP1L1-PDGFRA rearrangement associated with acute myeloid leukaemia is extremely rare. Here, we report a rare case of FIP1L1-PDGFRA-positive acute myeloid leukaemia, with marked peripheral blood and bone marrow eosinophilia, treated with low dose of imatinib monotherapy, achieving a rapid and long-lasting complete cytologic and molecular remission, without need for intensive chemotherapy.

Comparison of two real-time quantitative polymerase chain reaction strategies for minimal residual disease evaluation in lymphoproliferative disorders: correlation between immunoglobulin gene mutation load and real-time quantitative polymerase chain reaction performance.

We compared two strategies for minimal residual disease evaluation of B-cell lymphoproliferative disorders characterized by a variable immunoglobulin heavy chain (IGH) genes mutation load. Twenty-five samples from chronic lymphocytic leukaemia (n = 18) or mantle cell lymphoma (n = 7) patients were analyzed. Based on IGH variable region genes, 22/25 samples carried > 2% mutations, 20/25 > 5%. In the IGH joining region genes, 23/25 samples carried > 2% mutations, 18/25 > 5%. Real-time quantitative polymerase chain reaction was performed on IGH genes using two strategies: method A utilizes two patient-specific primers, whereas method B employs one patient-specific and one germline primer, with different positions on the variable, diversity and joining regions. Twenty-three samples (92%) resulted evaluable using method A, only six (24%) by method B. Method B poor performance was specifically evident among mutated IGH variable/joining region cases, although no specific mutation load above, which the real-time quantitative polymerase chain reaction failed was found. The molecular strategies for minimal residual disease evaluation should be adapted to the B-cell receptor features of the disease investigated.

R-COMP 21 for frail elderly patients with aggressive B-cell non-Hodgkin lymphoma: a pilot study.

We evaluated the toxicity and efficacy of nonpegylated liposomal doxorubicin (Myocet) when substituted for conventional doxorubicin in the CHOP-21 regimen in the treatment of frail elderly patients with aggressive non-Hodgkin lymphoma. Twenty frail patients (median age, 73 years), as defined by Balducci et al., with diffuse large B cell or grade IIIb follicular lymphoma, either at diagnosis (15 patients) or relapsed (five patients), were prospectively enrolled. Nine out of 20 (45%) had a World Health Organisation (WHO) performance status > or =2. Fifteen out of 20 patients (75%) had an International Prognostic Index (IPI) score > or =3. Thirteen out of 20 (65%) evaluable patients obtained a complete response. Five additional patients (25%) achieved a partial response. With a median follow-up of 24 months (range 18-27), 15/18 responding patients (83%) are alive and disease free, as well as 3/18 are alive with active disease. Toxicity was mainly hematological with grade 3/4 neutropenia in 26% of cycles and febrile neutropenia in 5%. However, 3/20 patients presented a grade III-IV WHO toxicity (one fatal pulmonary embolism, one congestive, and one ischemic heart failure) while receiving R-COMP chemotherapy. In conclusion, R-COMP-21 is an effective regimen with promising response rates for frail and elderly patients with aggressive non-Hodgkin lymphoma.

Mini-ICE effectively mobilises peripheral blood stem cells after fludarabine-based regimens in acute myeloid leukaemia.

Fludarabine-based cycles severely impair mobilisation and collection of peripheral blood stem cells (PBSC) in acute myeloid leukaemia (AML). In an effort of reversing this side-effect, we studied the action on mobilisation and collection of PBSC of a low-dose regimen: 5-d Mini-ICE (oral idarubicin and etoposide; subcutaneous cytosine arabinoside) administered after fludarabine-based regimens in seven adult AML patients. Leukapheresis were started when the CD34+ cell count was more than 10/microL. The median number of harvested CD34+ cells was 8.1 x 10(6)/kg (range 3.08-15.2). All the patients were successfully submitted to PBSC transplantation. Median times to neutrophil and platelet recovery were rapid with a normal transfusional support. We suggest that the Mini-ICE programme is feasible, well tolerated and effective in terms of PBSC mobilisation and collection in low-yield AML patients previously treated with fludarabine. It is well known that a negative effect on stem cell mobilisation and harvest is observed not only after fludarabine administration in AML or low-grade lymphomas, but also after cycles based on different agents, such as thalidomide in multiple myeloma. This preliminary experience, if confirmed on larger series and/or other haematological malignancies, could open new opportunities to perform autologous PBSC transplantation in heavily pretreated cases, allowing a full source of therapeutic options before the start of the mobilisation process.