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Within the Campus ALL network we analyzed the incidence, characteristics, treatment and outcome of a central nervous system (CNS) relapse in 1035 consecutive adult acute lymphoblastic leukemia (ALL) patients treated frontline with pediatric-inspired protocols between 2009 and 2020. Seventy-one patients (6.8%) experienced a CNS recurrence, more frequently in T- (28/278; 10%) than in B-ALL (43/757; 5.7%) (p = 0.017). An early CNS relapse-< 12 months from diagnosis-was observed in 41 patients. In multivariate analysis, risk factors for early CNS relapse included T-cell phenotype (p = <0.001), hyperleucocytosis >100 × 10 9 /L (p<0.001) and male gender (p = 0.015). Treatment was heterogeneous, including chemotherapy, radiotherapy, intrathecal therapy and novel agents. A complete remission (CR) was obtained in 39 patients (55%) with no differences among strategies. After CR, 26 patients underwent an allogenic transplant, with a significant overall survival benefit compared to non-transplanted patients (p = 0.012). After a median observation of 8 months from CNS relapse, 23 patients (32%) were alive. In multivariate analysis, the time to CNS relapse was the strongest predictor of a lower 2-year post-relapse survival (p<0.001). In conclusion, in adult ALL the outcome after a CNS relapse remains very poor. Effective CNS prophylaxis remains the best approach and allogenic transplant should be pursued when possible., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Metaphase (M-) and array (A-) Comparative Genomic Hybridization (CGH) were used to investigate 40 cases of T- and 32 of B-cell acute lymphoblastic leukaemia (ALL) with normal/failed cytogenetics. M-CGH was performed in all cases and A-CGH in 10/12 T-ALL cases with uncertain/normal M-CGH results. M-CGH was abnormal in 38/72 cases, with a total of 110 imbalances (60 gains, 50 losses). 25/40 patients with T-ALL (62.5%) showed 77 imbalances, with at least 1 genomic imbalance and a mean of 3 aberrations/patient (range 1-12). 13/32 patients with B-ALL (40.6%) presented 34 imbalances, with a mean of 2.6 imbalances (range 1-8). A-CGH detected 4 more T-ALL cases with genomic imbalances. A-CGH identified NF1/17q11.2 deletion and interphase fluorescence in situ hybridization provided a 10.8% estimated overall incidence of NF1/17q11.2 deletion in T-ALL. In all but one case (6/7) with NF1 deletion, denaturing high-performance liquid chromatography and direct sequencing detected NOTCH1 gene mutations. Three or more imbalances in CGH-positive cases were significantly associated with resistance to treatment and death during or after induction therapy. We suggest that the work-up for ALL at diagnosis should include CGH investigations, particularly when cytogenetics is uninformative, because they may provide potentially valuable information with prognostic and therapeutic implications.

SBDS/7q11 gene mutations underlie the congenital Shwachman Diamond syndrome (SDS), characterized by bone marrow failure and high risk of haematological malignancies. In two cases of SDS with bone marrow failure and isolated del(20q) interphase fluorescence in situ hybridization (I-FISH) found no abnormalities in FHIT/3p14.2, IKZF1/7p13, D7S486/7q31, PTEN/10q23.3, WT1/11p13, ATM/11q23, D13S25/13q14, TP53/17p13, NF1/17q11, SMAD2/18q21, RUNX1/21q22. Fluorescence immunophenotype combined with I-FISH found del(20q) in a totipotent haematopoietic stem cell (CD34(+), CD133(+)) and downstream myelocyte (CD33(+), CD14(+), CD13(+)), erythrocyte (Glycophorin A(+)) and lymphocyte lineages (CD19(+), CD20(+), CD3(+), CD7(+)). These findings and clinical follow-ups confirm the benign course of SDS with isolated del(20q).

Two cases of T acute lymphoblastic leukaemia (T-ALL) with an identical t(4;11)(q21;p15) translocation were identified within a prospective study on the biological and clinical features of adult ALL patients enrolled into the therapeutic protocol ALL0496 of the GIMEMA Italian Group. In both cases, the molecular characterization showed an involvement of the NUP98 gene on 11p15 which rearranges with the RAP1GDS1 gene on 4q21. The morphological and immunological features of the leukaemic cells, as well as the clinical behaviour and response to induction therapy, were the same in both patients. Based on the available data, the t(4;11)(q21;p15) translocation involving the NUP98-RAP1GDS1 fusion gene emerges as a new highly specific genetic abnormality that characterizes a subset of T-ALL.

Acute myeloid disorders with rearrangements of 12p outside the ETV6 gene were characterized by fluorescence in situ hybridization (FISH) with a panel of DNA probes. Seven patients with de novo acute myeloid leukaemia (AML), one with secondary acute myeloid leukaemia (sAML), and one in the blast phase of chronic myeloid leukaemia (CML-BP) were enrolled in the study. All AML cases showed multiple karyotypic changes. Chromosome 5 and/or 7 deletions were the most frequent accompanying changes. FISH revealed amplification, cryptic translocation, and fragmentation of chromosome 12, not discernible at karyotypic level. Different karyotypic rearrangements of 12p showed a common molecular event. Among the seven cases in which breakpoints could be determined, six were telomeric and one centromeric to ETV6. In three AML cases a new recurrent breakpoint in the telomeric region was identified distally to locus D12S158 and to pac 922B22 which is the most telomeric probe available for 12p. Accompanying cryptic deletions were also detected in five patients and the commonly deleted region, of around 700 kb, included the ETV6 gene and the D12S391 locus.