Identification of putative noncanonical driver mutations in patients with essential thrombocythemia.

Essential thrombocythemia (ET) cases without canonical JAK2, CALR, or MPL mutations, that is, triple-negative (TN) ET, have been found in 10%-20% of ET cases. Owing to the limited number of TN ET cases, its clinical significance remains unclear. This study evaluated TN ET's clinical characteristics and identified novel driver mutations. Among 119 patients with ET, 20 (16.8%) had no canonical JAK2/CALR/MPL mutations. Patients with TN ET tended to be younger and had lower white blood cell counts and lactate dehydrogenase values. We identified putative driver mutations in 7 (35%): MPL S204P, MPL L265F, JAK2 R683G, and JAK2 T875N were previously reported as candidate driver mutations in ET. Moreover, we identified a THPO splicing site mutation, MPL*636Wext*12, and MPL E237K. Four of the seven identified driver mutations were germline. Functional studies on MPL*636Wext*12 and MPL E237K revealed that they are gain-of-function mutants that increase MPL signaling and confer thrombopoietin hypersensitivity with very low efficiency. Patients with TN ET tended to be younger, although this was thought to be due to the inclusion of germline mutations, hereditary thrombocytosis. Accumulating the genetic and clinical characteristics of noncanonical mutations may help future clinical interventions in TN ET and hereditary thrombocytosis.

Development of a modified prognostic index for patients with aggressive adult T-cell leukemia-lymphoma aged 70 years or younger: possible risk-adapted management strategies including allogeneic transplantation.

Adult T-cell leukemia-lymphoma is a distinct type of peripheral T-cell lymphoma caused by human T-cell lymphotropic virus type I. Although allogeneic stem cell transplantation after chemotherapy is a recommended treatment option for patients with aggressive adult T-cell leukemia-lymphoma, there is no consensus about indications for allogeneic stem cell transplantation because there is no established risk stratification system for transplant eligible patients. We conducted a nationwide survey of patients with aggressive adult T-cell leukemia-lymphoma in order to construct a new, large database that includes 1,792 patients aged 70 years or younger with aggressive adult T-cell leukemia-lymphoma who were diagnosed between 2000 and 2013 and received intensive first-line chemotherapy. We randomly divided patients into two groups (training and validation sets). Acute type, poor performance status, high soluble interleukin-2 receptor levels (> 5,000 U/mL), high adjusted calcium levels (≥ 12 mg/dL), and high C-reactive protein levels (≥ 2.5 mg/dL) were independent adverse prognostic factors used in the training set. We used these five variables to divide patients into three risk groups. In the validation set, median overall survival for the low-, intermediate-, and high-risk groups was 626 days, 322 days, and 197 days, respectively. In the intermediate- and high-risk groups, transplanted recipients had significantly better overall survival than non-transplanted patients. We developed a promising new risk stratification system to identify patients aged 70 years or younger with aggressive adult T-cell leukemia-lymphoma who may benefit from upfront allogeneic stem cell transplantation. Prospective studies are warranted to confirm the benefit of this treatment strategy.

A decrease in newly diagnosed patients with adult T-cell leukemia/lymphoma in Kagoshima, a highly endemic area of HTLV-1 in southwestern Japan.

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell malignancy caused by human T-cell leukemia virus type-I (HTLV-1). This study investigated whether the number of newly diagnosed patients with ATL is decreasing in the background of a declining number of individuals infected by HTLV-1 in Kagoshima, Japan, one of the most endemic areas of HTLV-1 in the world. We retrospectively analyzed the number of newly diagnosed patients with ATL between January 2001 and December 2021 in three major hospitals. The number of newly diagnosed patients with B-cell non-Hodgkin lymphoma (B-NHL) in the same period was examined as an internal control. One thousand eighteen and 2,029 patients with ATL and B-NHL were registered, respectively. The age-adjusted incidence of ATL steadily increased between 2001 and 2012, whereas that between 2013 and 2021 decreased. Despite the limitation of its retrospective nature, this is the first report indicating a decrease in ATL patients in Japan.

Copper-transporting P-type ATPase, ATP7A, confers multidrug resistance and its expression is related to resistance to SN-38 in clinical colon cancer.

We and others have shown that the copper transporters ATP7A and ATP7B play a role in cellular resistance to cis-diaminedichloroplatinum (II) (CDDP). In this study, we found that ATP7A transfection of Chinese hamster ovary cells (CHO-K1) and fibroblasts isolated from Menkes disease patients enhanced resistance not only to CDDP but also to various anticancer drugs, such as vincristine, paclitaxel, 7-ethyl-10-hydroxy-camptothecin (SN-38), etoposide, doxorubicin, mitoxantron, and 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11). ATP7A preferentially localized doxorubicin fluorescence to the Golgi apparatus in contrast to the more intense nuclear staining of doxorubicin in the parental cells. Brefeldin A partially and monensin completely altered the distribution of doxorubicin to the nuclei in the ATP7A-expressing cells. ATP7A expression also enhanced the efflux rates of doxorubicin and SN-38 from cells and increased the uptake of SN-38 in membrane vesicles. These findings strongly suggested that ATP7A confers multidrug resistance to the cells by compartmentalizing drugs in the Golgi apparatus and by enhancing efflux of these drugs, and the trans-Golgi network has an important role of ATP7A-related drug resistance. ATP7A was expressed in 8 of 34 (23.5%) clinical colon cancer specimens but not in the adjacent normal epithelium. Using the histoculture drug response assay that is useful for the prediction of drug sensitivity of clinical cancers, ATP7A-expressing colon cancer cells were significantly more resistant to SN-38 than ATP7A-negative cells. Thus, ATP7A confers resistance to various anticancer agents on cancer cells and might be a good index of drug resistance in clinical colon cancers.

VCAP-AMP-VECP as a preferable induction chemotherapy in transplant-eligible patients with aggressive adult T-cell leukemia-lymphoma: a propensity score analysis.

A dose-intensified multi-agent chemotherapy regimen called VCAP-AMP-VECP was investigated in Japan as front-line therapy for patients with adult T-cell leukemia-lymphoma (ATL). Although a prospective randomized controlled study showed that VCAP-AMP-VECP was superior to CHOP, the trial was rather small and no subsequent studies confirmed the benefit of VCAP-AMP-VECP over CHOP. We conducted a retrospective analysis of transplant-eligible patients with ATL who received only VCAP-AMP-VECP or CHOP, incorporating inverse probability of treatment weighting (IPTW) using propensity scoring. Overall, 947 and 513 patients were treated with VCAP-AMP-VECP and CHOP, respectively. The median follow-up of surviving patients was 1006 days. The crude probabilities of 2-year overall survival (OS) for patients in the VCAP-AMP-VECP and CHOP groups were 31.2% and 24.6%, respectively (P < 0.001). Stratified by risk group according to the modified ATL-prognostic index score at diagnosis, the crude probabilities of 2-year OS in the VCAP-AMP-VECP and CHOP groups were 39.8 and 45.0% in the low-risk group (P = 0.69), 32.2 and 21.6% in the intermediate-risk group (P < 0.001), and 17.2 and 6.2% in the high-risk group (P = 0.005). Our current analysis suggests that VCAP-AMP-VECP regimen is a preferable front-line therapy in patients with aggressive ATL in intermediate- and high-risk groups.

Aggressive NK cell leukaemia after splenectomy: association with CD95-resistant memory T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome.

We describe a 44-yr-old Japanese woman with persistent polyclonal T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome (HPS). T cells bearing alphabeta T-cell receptors (TCR) expressed increased amounts of CD95 and of CD45RO, which are phenotypically memory T cells. The TCR repertoire was broad and diverse. Regardless of CD95 expression, these cells were resistant to CD95-mediated apoptosis. Aggressive natural killer cell leukaemia (ANKL) without an association with Epstein-Barr virus was detected 1 month after therapeutic splenectomy that followed 3 yr of immunosuppressive therapy against HPS. The immunophenotype of these leukaemia cells was CD56, CD16(dim), CD7, CD45RA and they expressed some CD2, CD8 and HLA-DR. Moreover, hyperdiploid clones with complex chromosomal abnormalities were also detected. Latent NK-cell malignancy seemed to cause the CD95-resistant memory T-cell proliferation and splenectomy resulted in overt ANKL progression. There should be careful consideration of the risks versus benefits of splenectomy in HPS, in light of the possibility of fatal leukaemia/lymphoma progression.

Two cases of secondary acute myeloid leukemia accompanying adult T-cell leukemia/lymphoma.

We identified 2 cases of secondary acute myeloid leukemia (AML) following adult T-cell leukemia/lymphoma (ATL) in patients who had previously received chemotherapy. Both cases were thought to represent therapy-related AML because the patients had previously received combination chemotherapy including epipodophyllotoxin, anthracycline, and alkylating agents for the ATL. The cases were diagnosed as AML M4 with eosinophilia and AML M2, with the chromosomal abnormalities inv(16)(p13q22) and t(8;21)(q22;q22), respectively. In our hospital, only these 2 cases of secondary AML accompanying ATL were identified among 90 cases of acute- or lymphoma-type ATL diagnosed from October 1999 to July 2006. The frequency of coexisting AML and ATL is lower than that reported for acute leukemia coexisting with other lymphoid malignancies. The low frequency of secondary leukemia with ATL may be associated with the short survival times of ATL patients.

A new cytogenetic abnormality, t(2;7)(q33;q36), in acute promyelocytic leukemia.

We report the case of a patient with acute promyelocytic leukemia (APL) carrying a novel chromosomal abnormality, t(2;7)(q33;q36). The 54-year-old woman was morphologically diagnosed with APL through bone marrow aspiration. The proportion of blast cells in bone marrow was 78%, including cells displaying Auer rods and faggot cells. Chromosomal analysis revealed the karyotype 46,XX,t(2;7)(q33;q36)[17]/46,XX[3]. The t(15;17) was not detected with conventional cytogenetic analysis. However, reverse transcriptase-polymerase chain reaction revealed the presence of a PML/RARA fusion gene. Cells displaying t(2;7)(q33;q36) disappeared after complete remission was achieved, using induction chemotherapy. Although several additional chromosomal abnormalities have been reported, this t(2;7)(q33;q36) without the classic t(15;17) represents a novel chromosomal abnormality associated with APL.

Adult T-cell leukemia in a liver transplant recipient that did not progress after onset of graft rejection.

A liver allograft recipient developed acute-type adult T-cell leukemia (ATL) during tacrolimus treatment, 2 years after undergoing transplantation for subacute fulminant hepatitis. Both donor and recipient were asymptomatic carriers of human T-cell lymphotropic virus type I (HTLV-I), but the ATL cells originated from the recipient. Tacrolimus treatment was discontinued, and combination chemotherapy was administered. The patient achieved complete remission, but the transplanted liver was acutely and chronically rejected. The patient did not respond to rescue therapy with tacrolimus, prednisolone, and mycophenolate mofetil and died of hepatic failure. Liver biopsies showed CD4+ ATL cell infiltration at the onset of ATL but not at the terminal stage. Moreover, Southern blotting revealed clonal integration of HTLV-I into the host genome of lymphoma cells at onset but not at the terminal stage. ATL after liver transplantation has not been previously described. The clinical course of the posttransplantational ATL was atypical, because it did not progress after the onset of rejection.

Acute Myeloid Leukemia Diagnosed 5 Years after Adult T-Cell Leukemia/Lymphoma.

A case of secondary acute myeloid leukemia (AML) was identified following adult T-cell leukemia/lymphoma (ATL), for which combination chemotherapy had been administered, including epipodophyllotoxin, anthracycline, and alkylating agents. AML with maturation was diagnosed by the cytological findings, cell surface markers, and chromosomal abnormalities. We previously reported two cases of AML accompanied by ATL. In this case of AML after chemotherapy for ATL, we considered that the AML was probably associated with previous chemotherapy for ATL. Although the ATL remained in remission, the therapy-related AML with complex chromosomal abnormalities proved resistant to chemotherapy, and the patient died from complications associated with AML.

A novel c-kit positive biphenotypic acute leukemia cell line, TMBL-1, carrying a p53 point mutation.

We established and characterized a c-kit positive cell line from the bone marrow of a patient with biphenotypic acute leukemia (BAL). The cell line, designated TMBL-1, carried a His-175 mutant p53. The immunophenotype of the primary leukemia cells at diagnosis was cytoplasmic CD3+, CD7+, CD13+, CD33-, interleukin-7 (IL-7) receptor+ and c-kit -. However, leukemia cells in relapse and TMBL-1 cells were CD33+ and c-kit +. Immunophenotypically, TMBL-1 is a BAL cell line that coexpresses T-lymphoid and myeloid markers which fulfill the criteria of the European Group for the Immunological Characterization of Leukemia. Stem cell factor (SCF), a key regulator of hematopoiesis signaling through c-kit, enhanced the proliferation of TMBL-1 cells. Direct sequencing revealed the conversion at codon 175 of the p53 gene in the TMBL-1 cells. Primary leukemia cells in relapse also carried the same point mutation but not at diagnosis. Moreover, TMBL-1 cells are sensitive to paclitaxel, which could induce p53-independent apoptosis. The biphenotypic features and p53 mutation may be associated with progression to a more malignant type. This cell line may provide new information on the role of SCF in the overlapping area between early T-lymphoid/myeloid cells, and help in the design of new therapies targeted towards p53 mutations.

Uncommon cases of immature-type CD56+ natural killer (NK)-cell neoplasms, characterized by expression of myeloid antigen of blastic NK-cell lymphoma.

Immature-type CD56(+) natural killer (NK)-cell neoplasms are classified as either myeloid/NK-cell precursor acute leukemia or blastic NK-cell lymphoma. We identified two cases of immature-type CD56(+) NK-cell neoplasms that were not categorizable as either of these entities. The first case involved a 74-year-old woman presenting with skin eruptions and pancytopenia due to bone marrow necrosis. Skin biopsy specimen revealed CD4(+), CD7(-), CD34(-), CD43(+), CD56(+), CD68(+), muramidase (lysozyme)(+), and myeloperoxidase (MPO)(-), and immunophenotyping of peripheral blood showed CD4(+), CD7(-), CD13(+), CD33(+), CD34(-), CD43(+), CD56(+), cytoplasmic (cy)CD68(+), CD123(+), and HLA-DR(+). The second case involved a 62-year-old man who had bilateral optic nerve tumor and presented with malignant cells in peripheral blood. Cell surface markers of malignant cells showed CD4(+), CD7(-), CD13(+), CD33(+), CD34(-), CD43(+), CD56(+), cyCD68(+), and HLA-DR(+). The phenotypes of tumor cells in both cases were compatible with blastic NK-cell lymphoma, except for the expression of myeloid antigen. Clinical presentations of these cases showed characteristics of both blastic NK-cell lymphoma and myeloid/NK-cell precursor acute leukemia.

Adult T-cell leukemia/lymphoma in a 21-year-old man.

Adult T-cell leukemia/lymphoma (ATL) is malignancy of mature T cells that caused by infection with human T-cell leukemia virus type I (HTLV-I). Leukemogenesis of ATL cells considered to involve a multistep oncogenic process, resulting in a very long latency period. But, we report here the case of a 21-year-old man having suffered from recurrent stomatititis who has already developed acute-type ATL. ATL generally occurs after a long latency period, and the present case in a young man is thus very rare.

Overexpression of survivin in primary ATL cells and sodium arsenite induces apoptosis by down-regulating survivin expression in ATL cell lines.

Patients with acute- or lymphoma-type adult T-cell leukemia (ATL) have a poor outcome because of the intrinsic drug resistance to chemotherapy. Protection from apoptosis is a common feature involved in multidrug-resistance of ATL. IAP (inhibitor of apoptosis) family proteins inhibit apoptosis induced by a variety of stimuli. In this study, we investigated the expression of IAP family members (survivin, cIAP1, cIAP2, and XIAP) in the primary leukemic cells from patients with ATL. We found that survivin was overexpressed in ATL, especially in acute-type ATL. Sodium arsenite was shown to down-regulate the expression of survivin at both the protein and RNA levels in a time- and dose-dependent manner, thus inhibiting cell growth, inducing apoptosis, and enhancing the caspase-3 activity in ATL cells. Nuclear factor-kappaB (NF-kappaB) enhances the transcriptional activity of survivin. Sodium arsenite suppressed the constitutive NF-kappaB activation by preventing the IkappaB-alpha degradation and the nuclear translocation of NF-kappaB. These findings suggest that survivin is an important antiapoptotic molecule that confers drug resistance on ATL cells. Sodium arsenite was shown to down-regulate the expression of survivin through the NF-kappaB pathway, thus inhibiting cell growth and promoting apoptosis of ATL cells.