Cyclin D1 expression in Rosai-Dorfman disease: a near-constant finding that is not invariably associated with mitogen-activated protein kinase/extracellular signal-regulated kinase pathway activation.

Activating mutations in the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway have been shown in nearly half of the cases of Rosai-Dorfman disease (RDD). Cyclin D1, a key cell cycle regulator, constitutes a major downstream target of the MAPK/ERK pathway. In this study, we aim to further understand the pathogenesis of RDD by assessing the lesional histiocytes for cyclin D1, p-ERK, Ki-67, and BCL-2 by immunohistochemistry. We assessed 35 samples of RDD and a control group of histiocyte-rich reactive lesions. Cyclin D1 was expressed in about 90% of cases of RDD. Cyclin D1 was positive in 25-95% (median, 85%) of lesional histiocytes, was moderately/strongly expressed in 97% of cyclin D1-positive cases, and was significantly higher than in control specimens. p-ERK was positive in 16 of 30 (53%) cases of RDD and was negative in all controls. All p-ERK-positive RDD cases had concurrent cyclin D1 expression, whereas more than a third of cyclin D1-positive cases were negative for p-ERK. Ki-67 was low in RDD (median, 3%). BCL-2 was positive in lesional histiocytes in nine of 10 RDD cases assessed. Overall, these findings point to unexpected, potential roles of these molecules in the pathogenesis of RDD. Overexpression of cyclin D1 in the absence of ERK phosphorylation in a subset of RDD cases opens the possibility of oncogenic mechanisms bypassing ERK and supports the notion that cyclin D1 overexpression in RDD is multifactorial. Moreover, the observed lack of correlation between cyclin D1 with Ki-67 proliferative index suggests that prosurvival actions of cyclin D1 are, at least in part, cell cycle independent. Finally, expression of BCL-2 and the low Ki-67 index suggest that RDD might be driven by antiapoptotic rather than proproliferative oncogenic mechanisms.

Chronic myeloid leukemia with insertion-derived BCR-ABL1 fusion: redefining complex chromosomal abnormalities by correlation of FISH and karyotype predicts prognosis.

Chromosomal insertion-derived BCR-ABL1 fusion is rare and mostly cryptic in chronic myeloid leukemia (CML). Most of these cases present a normal karyotype, and their risk and/or prognostic category are uncertain. We searched our database and identified 41 CML patients (20 M/21 F, median age: 47 years, range 12-78 years) with insertion-derived BCR-ABL1 confirmed by various FISH techniques: 31 in chronic phase, 1 in accelerated phase, and 9 in blast phase at time of diagnosis. Conventional cytogenetics analysis showed a normal karyotype (n = 19); abnormal karyotype with morphologically normal chromosomes 9 and 22 (n = 5); apparent ins(9;22) (n = 2) and abnormal karyotype with apparent abnormal chromosomes 9, der(9) and/or 22, der(22) (n = 15). The locations of insertion-derived BCR-ABL1 were identified on chromosome 22 (68.3%), 9 (29.3%), and 19 (2.4%). Complex chromosomal abnormalities were often overlooked by conventional cytogenetics but identified by FISH tests in many cases. After a median follow-up of 58 months (range 1-242 months), 11 patients died, and 3 lost contact, while the others achieved different cytogenetic/molecular responses. The locations of BCR-ABL1 (der(22) vs. non-der(22)) and the karyotype results (complex karyotype vs. noncomplex karyotype) by conventional cytogenetics were not associated with overall survival in this cohort. However, redefining the complexity of chromosomal abnormality by correlating karyotype and FISH findings, CML cases with simple chromosomal abnormalities had a more favorable overall survival than that with complex chromosomal abnormalities. We conclude that insertion-derived BCR-ABL1 fusions often involve complex chromosomal abnormalities which are overlooked by conventional cytogenetics, but can be identified by one or more FISH tests. We also suggest that the traditional cytogenetic response criteria may not apply in these patients, and the complexity of chromosomal abnormalities redefined by correlating karyotype and FISH findings can plays a role in stratifying patients into more suitable risk groups for predicting prognosis. (Word count: 292).

iAMP21 in acute myeloid leukemia is associated with complex karyotype, TP53 mutation and dismal outcome.

Acute myeloid leukemia (AML) with intrachromosomal amplification of chromosome 21 (iAMP21) is rare and has not been well characterized. We report 13 patients, 7 men and 6 women, with a median age of 65 years. Eleven patients presented with AML with myelodysplasia-related changes, and two patients had therapy-related AML. Cytopenias were detected in all patients (11 pancytopenia and two bi-lineage cytopenia). Myelodysplastic changes were observed in all 11 patients with adequate cells to evaluate. Myelofibrosis was present in ten patients. All patients had a complex karyotype, including abnormalities of chromosomes 5, 7, 17, and hsr(21)(q22), and ten patients showed TP53 deletion and/or mutation. Eleven patients received AML-based chemotherapy, one of whom also received hematopoietic stem cell transplant. By the end of the last follow-up, eight patients died with median survival of 3.2 months, four patients were alive with persistent AML, and one was in complete remission. The median overall survival was 6 months for all patients. We conclude that AML with iAMP21 is often associated with cytopenias, myelodysplasia, a complex karyotype, TP53 mutation/deletion, and a poor prognosis despite current therapies.

Data on MECOM rearrangement-driven chromosomal aberrations in myeloid malignancies.

Data in this article presents the results of conventional cytogenetics and fluorescence in situ hybridization (FISH) analyses in 129 patients with confirmed MECOM rearrangement (https://doi.org/10.1016/j.cancergen.2019.03.002) [1]. Generally, the MECOM rearrangement has arisen through translocation, inversion, and insertion and/or unknown mechanism. In addition to the typical chromosomal aberrations, inv(3)(q21q26.2) and t(3; 3)(q21; q26.6) [2-4], over 50% of cases presented here exhibit a wide spectrum of MECOM rearrangement-driven, atypical chromosomal aberrations, including inv(3) with breakpoint other than 3q21; t(1; 3); t(2; 3); t(3; 6); t(3; 8); t(3; 12); t(3; 17); t(3; 21) as well as an insertion of 3q26.2 into different chromosomes. These cases are thoroughly characterized by karyotyping, interphase-, metaphase-, map-back FISH and whole chromosomal painting (WCP) analyses.

Myeloid neoplasms with t(16;21)(q24;q22)/RUNX1-RUNX1T3 mimics acute myeloid leukemia with RUNX1-RUNX1T1.

Chromosome translocation t(16;21)(q24;q22)/RUNX1-RUNX1T3 is an infrequent but recurrent chromosomal abnormality identified in myeloid neoplasms, with only 25 cases have been reported to date. Here, we report eight cases (six women and two men) of myeloid neoplasms associated with t(16;21)(q24;q22): five with therapy-related myeloid neoplasms, two with relapsed acute myeloid leukemia (AML), and one with blast phase of chronic myeloid leukemia. Morphologic and immunophenotypic features include granulocytic dysplasia, blasts with prominent perinuclear hof, large orange-pink granules, long and slim Auer rods, and aberrant expression of CD19. Six patients received AML-based regimens, and five achieved complete remission after initial induction therapy. Our study suggests that myeloid neoplasm with t(16;21)/RUNX1-RUNX1T1 resembles AML with t(8;21)(q22;q22)/RUNX1-RUNX1T1, in regard to morphology, immunophenotype, and response to therapy. Therefore, the clinical management of AML with t(8;21) may provide the best model for patients with myeloid neoplasms with t(16;21).

Poor outcomes associated with +der(22)t(9;22) and -9/9p in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia receiving chemotherapy plus a tyrosine kinase inhibitor.

In patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) treated with chemotherapy plus a tyrosine kinase inhibitor (TKI), the prognostic impact of additional chromosomal abnormalities (ACAs) is not well-established. We evaluated the prognostic impact of individual ACAs in 152 patients with Ph+ ALL receiving first-line intensive chemotherapy plus either imatinib (n = 36), dasatinib (n = 74), or ponatinib (n = 42). ACAs were identified in 118 patients (78%). Compared to outcomes of patients without ACAs, ACAs were not associated with differences in either relapse-free survival (RFS; P = 0.42) or overall survival (OS; P = 0.51). When individual ACAs were evaluated, +der(22)t(9;22) and/or -9/9p in the absence of high hyperdiploidy (HeH) was present in 16% of patients and constituted a poor-risk ACA group. Patients with one or more poor-risk ACAs in the absence of HeH had significantly shorter RFS (5-year RFS rate 33% versus 59%, P = 0.01) and OS (5-year OS rate 24% versus 63%, P = 0.003). Poor-risk ACAs were prognostic in patients who received imatinib and dasatinib but not in those who received ponatinib. By multivariate analysis, this poor-risk ACA group was independently associated with worse RFS (HR 2.03 [95% CI 1.08-3.30], P = 0.03) and OS (HR 2.02 [95% CI 1.10-3.71], P = 0.02). Patients with Ph+ ALL who have +der(22)t(9;22) and/or -9/9p in the absence of HeH have relatively poor outcomes when treated with chemotherapy plus a TKI.

Immunoglobulin gene expression in umbilical cord blood-derived CD34⁺ hematopoietic stem/progenitor cells.

Recently, immunoglobulin (Ig) expression was reported in a variety of non-B lineage cells, including myeloid cells. We assessed whether hematopoietic stem/progenitor cells (HSC/HPCs) can express Ig. With Gene Expression Omnibus (GEO) microarray database analysis, we found that IGHM was expressed with the highest frequency and level in umbilical cord blood CD34(+) HSC/HPCs, followed by IGK@, IGHE, IGHD, IGHG1, and IGHA1, while IGL@ was nearly not expressed. Ig expression was further confirmed by molecular experiments and immunofluorescence. Moreover, HSC/HPCs-derived Ig displayed restricted/biased usages and VHDJH rearrangement patterns. These results suggest that Igs, especially IgM, may have a role in CD34(+) HSC/HPCs function.

Absence of terminal deoxynucleotidyl transferase expression identifies a subset of high-risk adult T-lymphoblastic leukemia/lymphoma.

Terminal deoxynucleotidyl transferase (TdT) can be downregulated in minimal residual disease of T-acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) after chemotherapy. TdT-negative T-ALL/LBL cases are rare and have not been well characterized. We studied the clinicopathologic features of de novo T-ALL/LBL patients treated at our institution during 2003-2011, with an emphasis on immunophenotype and survival of TdT-negative versus TdT-positive cases. Absence of TdT expression was defined as <10% lymphoblasts positive. Seven (12%) TdT-negative cases were identified from a cohort of 59 de novo T-ALL/LBL. The TdT-negative and TdT-positive cases were similar with regard to gender, percentage of patients with a high leukocyte count (>100 × 10(9)/l), central nervous system involvement, and an abnormal karyotype. However, patients with TdT-negative T-ALL/LBL had a significantly higher rate of disease progression and shorter overall survival. Although not statistically significant, TdT-negative T-ALL/LBL cases were associated with an older median age and higher percentage of 'early T precursor' (ETP) immunophenotype than TdT-positive cases. Absence of TdT expression identifies a subset of high-risk T-ALL/LBL that overlaps with, but is not identical to, the ETP leukemia, providing additional prognostic value.