Correction to: Cell dynamics during differentiation therapy with all-trans retinoic acid in acute promyelocytic leukemia.

In the original publication of the article, Table 2 was published incorrectly. The column names were swapped under the column heading "Prom (%)". The correct column names are PB and BM.

Cell dynamics during differentiation therapy with all-trans retinoic acid in acute promyelocytic leukemia.

The introduction of all-trans retinoic acid (ATRA) has made acute promyelocytic leukemia (APL) a curable disease; however, early death prior to the completion of treatment remains a problem. In quantitative evaluation of response to ATRA treatment, lymphocytes must be excluded as they do not originally have t(15;17). We categorized peripheral blood leukocytes by nuclear morphology into polymorphonuclear cells (PMNs) comprising segmented granulocytes, and non-polymorphonuclear cells (NPMs) which includes lymphocytes, monocytes, band cells, and immature myeloid cells. We consecutively evaluated the ratio of t(15;17)-positive cells using fluorescence in situ hybridization in eight newly diagnosed patients with APL. We confirmed the differentiation of APL cells until cytogenetic complete remission; the association of a decrease of t(15;17)-positive NPMs and an increase of t(15;17)-positive PMNs was followed by a decrease of t(15;17)-positive PMNs. The kinetic pattern of t(15;17)-positive NPMs and PMNs was consistent in most patients, irrespective of leukocyte counts at diagnosis, additional chromosomal changes, and ATRA with or without chemotherapies. Kinetic analysis enables us to evaluate treatment response and the recovery of normal hematopoiesis in individuals.

[MALT lymphoma with t (X;14) (p11.2;q32) developing during the course of cutaneous leukocytoclastic angitis].

A 73-year-old man with left parotid gland swelling over 2 months was referred to our hospital in March 201X. Purpura on the lower legs had been recurrent for >20 years. Biopsy of the parotid gland demonstrated diffuse infiltration of abnormal lymphocytes that were negative for CD10 and positive for CD19, CD20, and κ-chain. The Ki-67 positivity was <10%; lymphoepithelial lesions were observed. The patient was diagnosed with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Chromosome analysis revealed t (X;14) (p11.2;q32), and fluorescence in situ hybridization (FISH) of metaphase spreads showed three signals of the immunoglobulin heavy chain (IGH) gene on the derivative chromosomes X and 14, besides the normal chromosome 14. CT findings of parotid glands were suggestive of Sjogren syndrome, and biopsy of the purpura on the leg demonstrated leukocytoclastic vasculitis. In the literature, only seven patients with lymphoma and t (X;14) translocation have been reported. Of these, five patients had MALT lymphoma, one had nodal marginal zone lymphoma, and one had diffuse large B-cell lymphoma. In all patients, lymphoma evolved from previous autoimmune diseases. It is suggested that MALT lymphoma with the t (X;14) translocation forms a new entity of lymphoma.

Acute myeloid leukemia with t (3;8) (q26.2;q24), a simple variant of 3q26.2/EVI1 translocation.

A 70-year-old man with pancytopenia was referred to our hospital. His bone marrow comprised 75.4% leukemic blast cells and increased micromegakaryocytes. The leukemic cells were positive for myeloperoxidase and expressed CD2, CD13, CD33, CD34, CD56, CD117, HLA-DR, and MYC. Chromosomal analysis revealed 45,XY,t (3;8) (q26.2;q24),-7[6]/46,XY[14]. Fluorescence in situ hybridization revealed the rearrangement of the ecotropic viral integration site 1 (EVI1) gene. Thus, the patient was diagnosed as having acute myeloid leukemia (AML) with maturation, according to the WHO classification; he achieved complete cytogenetic remission after two courses of combination chemotherapy using anthracyclines and cytarabine. The t (3;8) translocation is a rare simple variant of the 3q26.2/EVI1 translocation, which is an adverse prognostic factor of AML. Clarifying the clinical features of leukemia in patients with simple variant translocations facilitates the development of therapies.

Acute myeloid leukemia with t(3;21)(q13;q22), a novel simple variant of the 21q22/RUNX1 translocation.

A 69-year-old man diagnosed with leukocytosis was referred to our hospital in July 201X. The patient was diagnosed as having a myelodysplastic/myeloproliferative neoplasm. However, he presented with leukemia 2 months later. Chromosomal analysis of a bone marrow sample documented that this patient had a normal karyotype. The patient was successfully treated with idarubicin and cytarabine, and he underwent three courses of consolidation therapy. However, he suffered a relapse in May of the following year. A cytogenetic analysis revealed the presence of a t (3;21) (q13;q22) translocation, and fluorescence in situ hybridization of metaphase spreads detected three signals corresponding to the runt related transcription factor 1 (RUNX1) on the derivative chromosomes 3 and 21, besides the normal chromosome 21. Chromosomal translocations in leukemia often involve genes encoding transcription factors, and the RUNX1 is a common target for such translocations. To the best of our knowledge, this is a novel variant of the RUNX1 translocation. Identifying genes associated with translocations in leukemia contributes to novel insights into the mechanisms of disease progression and chemotherapy resistance and also facilitates the development of molecularly targeted therapies.

PAX5-positive plasma cell myeloma with t(9;14;11)(p13;q32;q13), a novel complex variant translocation of t(11;14)(q13;q32) and t(9;14)(p13;q32).

We describe herein the case of a 64-year-old man with a diagnosis of plasma cell myeloma (PCM). A chromosome analysis based on G-banding and spectral karyotyping revealed the following complex karyotype: 46,XY,del(3)(p?), t(4;15)(q31;q24),t(9;14;11)(p13;q32;q13),add(15)(q24),add(18)(q21). Fluorescence in situ hybridization (FISH) detected one signal each for the immunoglobulin heavy chain (IGH) and cyclin D1 (CCND1) genes, and three fusion signals of IGH and CCND1. FISH analysis of metaphase spreads revealed fusion signals on the derivative chromosomes 9, 11, and 14. Immunohistochemical analysis identified abnormal expression of CCND1 and PAX5. PAX5-positive PCM is rare because the down-regulation of PAX5 is essential for the terminal differentiation of B cells into plasma cells. To the best of our knowledge, this is the first reported case of a novel complex variant translocation of t(11;14)(q13;q32) and t(9;14)(p13;q32).

Cytogenetic Study and Analysis of Protein Expression in Plasma Cell Myeloma with t(11;14)(q13;q32): Absence of BCL6 and SOX11, and Infrequent Expression of CD20 and PAX5.

The t(11;14)(q13;q32) translocation is the most common chromosomal translocation in plasma cell myeloma (PCM), but the cytogenetic and immunophenotypic features of PCM with t(11;14)(q13;q32) remain to be fully elucidated. To address the issue, we retrospectively analyzed 21 newly diagnosed PCM patients with the t(11;14)(q13;q32) translocation in our institute. CD20 is a B-cell-specific transmembrane protein that is the topic of much focus as a potential target in immunotherapy. We observed a low incidence of CD20 expression (2 of 21 patients, 11%), although the expression of CD20 was previously reported to be associated with t(11;14)(q13;q32). PAX5 is an essential transcriptional factor involved in B-cell development and commitment, and is down-regulated upon plasma cell differentiation. We observed one patient (6%) with expression of PAX5. The expression of CD19, CD56, and CD138 was detected in one (0.7%), nine (60%), and 13 patients (87%), respectively. Cyclin D1, CD38, and BCL2 were detected in all patients; on the other hand, neither BCL6 nor SOX11 was detected in any of the evaluated patients. Abnormalities of chromosome 13 were detected in six patients (38%), but deletion of TP53 was not observed in any of the evaluated patients. Our results suggest the absence of BCL6 and SOX11 expression, and infrequent expression of CD20, PAX5, and CD56 in PCM with t(11;14)(q13;q32), in contrast to the findings of earlier reports.