Integrated molecular analysis of adult T cell leukemia/lymphoma

Adult T cell leukemia/lymphoma (ATL) is a peripheral T cell neoplasm of largely unknown genetic basis, associated with human T cell leukemia virus type-1 (HTLV-1) infection. Here we describe an integrated molecular study in which we performed whole-genome, exome, transcriptome and targeted resequencing, as well as array-based copy number and methylation analyses, in a total of 426 ATL cases. The identified alterations overlap significantly with the HTLV-1 Tax interactome and are highly enriched for T cell receptor-NF-κB signaling, T cell trafficking and other T cell-related pathways as well as immunosurveillance. Other notable features include a predominance of activating mutations (in PLCG1, PRKCB, CARD11, VAV1, IRF4, FYN, CCR4 and CCR7) and gene fusions (CTLA4-CD28 and ICOS-CD28). We also discovered frequent intragenic deletions involving IKZF2, CARD11 and TP73 and mutations in GATA3, HNRNPA2B1, GPR183, CSNK2A1, CSNK2B and CSNK1A1. Our findings not only provide unique insights into key molecules in T cell signaling but will also guide the development of new diagnostics and therapeutics in this intractable tumor.

Aberrant PD-L1 expression through 3'-UTR disruption in multiple cancers

Successful treatment of many patients with advanced cancer using antibodies against programmed cell death 1 (PD-1; also known as PDCD1) and its ligand (PD-L1; also known as CD274) has highlighted the critical importance of PD-1/PD-L1-mediated immune escape in cancer development. However, the genetic basis for the immune escape has not been fully elucidated, with the exception of elevated PD-L1 expression by gene amplification and utilization of an ectopic promoter by translocation, as reported in Hodgkin and other B-cell lymphomas, as well as stomach adenocarcinoma. Here we show a unique genetic mechanism of immune escape caused by structural variations (SVs) commonly disrupting the 3' region of the PD-L1 gene. Widely affecting multiple common human cancer types, including adult T-cell leukaemia/lymphoma (27%), diffuse large B-cell lymphoma (8%), and stomach adenocarcinoma (2%), these SVs invariably lead to a marked elevation of aberrant PD-L1 transcripts that are stabilized by truncation of the 3'-untranslated region (UTR). Disruption of the Pd-l1 3'-UTR in mice enables immune evasion of EG7-OVA tumour cells with elevated Pd-l1 expression in vivo, which is effectively inhibited by Pd-1/Pd-l1 blockade, supporting the role of relevant SVs in clonal selection through immune evasion. Our findings not only unmask a novel regulatory mechanism of PD-L1 expression, but also suggest that PD-L1 3'-UTR disruption could serve as a genetic marker to identify cancers that actively evade anti-tumour immunity through PD-L1 overexpression.

Tumour-immune microenvironment in duodenal-type follicular lymphoma

Despite duodenal-type follicular lymphoma (DTFL) being morphologically, immunophenotypically and genetically indistinguishable from nodal FL (nFL), this entity typically shows a significantly better prognosis. Here, we analysed the tumour immune microenvironments of diagnostic specimens from patients with DTFL (n = 30), limited-stage FL (LSFL; n = 19) and advanced-stage FL (ASFL; n = 31). The mean number of CD8⁺ tumour-infiltrating lymphocytes (TILs) in the neoplastic follicles was higher in DTFL (1,827/mm² ) than in LSFL (1,150/mm² ) and ASFL (1,188/mm² ) (P = 0·002, P = 0·002, respectively). In addition, CD8⁺ PD1^-  T cells with non-exhausting phenotype were more abundant in the peripheral blood (PB) of DTFL than in LSFL and ASFL, indicating that DTFL may exhibit a better and longer-lasting T cell-mediated immune response. Moreover, whereas FOXP3⁺ CTLA-4⁺ effector regulatory T cells (eTregs) were rarely observed in the neoplastic follicles of DTFL (mean: 12/mm² ), they were more abundant in LSFL (78/mm² ) and ASFL (109/mm² ) (P = 2·80 × 10^-5 , P = 4·74 × 10^-8 , respectively), and the numbers of eTregs correlated inversely with those of CD8⁺ TILs (r = -0267; P = 0·018). Furthermore, DTFL showed significantly fewer circulating FOXP3^hi CD45RA^- CD25^hi eTregs (0·146%) than ASFL (0·497%) and healthy controls (0·639%) (P = 0·0003, P = 6·79 × 10^-7 , respectively). These results suggest that the augmented anti-tumour immune reactions may contribute to a better prognosis on DTFL.

Targeted therapy for medullary and extramedullary relapse of FLT3-ITD acute myeloid leukemia following allogeneic hematopoietic stem cell transplantation

We report a case with extramedullary tumors affecting the supraclavicular region that presented as a relapse of acute myeloid leukemia (AML) with FLT3-ITD mutation after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Treatment with gilteritinib resulted in remarkable response with disappearance of both the medullary and extramedullary tumors. Subsequently, a 2nd allo-HSCT was performed in an attempt to cure his AML and complete molecular response has been sustained with gilteritinib resumption without worsening GVHD. Targeted therapy with gilteritinib for medullary and extramedullary relapse of FLT3-ITD AML could be effective and suitable as a bridging therapy for allo-HSCT.

The Impact of Hemodialysis and Liver Cirrhosis on the Plasma Concentrations of Tyrosine Kinase Inhibitors in a Patient with Chronic Myeloid Leukemia

We recently treated a chronic myeloid leukemia (CML) patient with liver and renal dysfunction, who was undergoing hemodialysis (HD). He was treated with 50 mg dasatinib (DAS) once daily just before HD. The maximum plasma concentration of DAS was 227 ng/mL on a non-HD day and 46.9 ng/mL on a HD day. He was subsequently treated with 200 mg bosutinib (BOS) once daily. The plasma concentration of BOS changed from 74.5 ng/mL before HD to 58.8 ng/mL after HD. Our results indicate that close monitoring of the plasma tyrosine kinase inhibitor concentrations should be considered in CML patients with organ impairment.

Low absolute lymphocyte count is a poor prognostic factor for untreated advanced follicular lymphoma treated with rituximab plus bendamustine: results of the prospective phase 2 CONVERT trial

The aim of this trial is to evaluate the utility of rituximab-bendamustine (R-B) for untreated advanced follicular lymphoma (FL) showing non-optimal response (nOR) to R-CHOP, and to identify clinical prognostic factors for FL patients receiving R-B. Patients who failed to achieve complete response/complete response unconfirmed (CR/CRu) [nOR-group] after 2 cycles of R-CHOP subsequently received 6 cycles of R-B. The primary endpoint was the 3-year progression-free survival (PFS) rate. Secondary endpoints included determination of prognostic factors. Fifty-six patients initially received R-CHOP, 43/56 patients (76.8%) were judged as nOR, and 33/43 patients (76.7%) completed 6 cycles of R-B. At a median follow-up of 50.6 months in the nOR-group, the 3-year PFS rate was 69.0%, and the 3-year overall survival (OS) rate was 92.7%. The most common toxicities associated with R-B were grade 3-4 lymphopenia (93.0%) and neutropenia (74.4%), both of which were manageable. A multivariate analysis including dose intensity, serum soluble interleukin-2 receptor, and FL international prognostic index-2 revealed low absolute lymphocyte count (<  869/μL) at diagnosis was an independent poor prognostic factor for both PFS and OS in the R-B-treated nOR-group. This result was further confirmed in validation cohorts including R-B-treated de novo (n = 40) and relapsed (n = 49) FL patients.

Decreased expression of T-cell-associated immune markers predicts poor prognosis in patients with follicular lymphoma

We previously examined the utility of rituximab-bendamustine (RB) in patients with follicular lymphoma (FL) exhibiting less than optimal responses to 2 cycles of the R-CHOP chemotherapy regimen. The aim of this study was to identify molecular biomarkers that can predict prognosis in RB-treated patients in the context of the prospective cohort. We first analyzed the mutational status of 410 genes in diagnostic tumor specimens by target capture and Sanger sequencing. CREBBP, KMT2D, MEF2B, BCL2, EZH2, and CARD11 were recurrently mutated as reported before, however none was predictive for progression-free survival (PFS) in the RB-treated patients (n = 34). A gene expression analysis by nCounter including 800 genes associated with carcinogenesis and/or the immune response showed that expression levels of CD8⁺ T-cell markers and half of the genes regulating Th1 and Th2 responses were significantly lower in progression of disease within the 24-mo (POD24) group (n = 8) than in the no POD24 group (n = 31). Collectively, we selected 10 genes (TBX21, CXCR3, CCR4, CD8A, CD8B, GZMM, FLT3LG, CD3E, EOMES, GZMK), and generated an immune infiltration score (IIS) for predicting PFS using principal component analysis, which dichotomized the RB-treated patients into immune IIS^high (n = 19) and IIS^low (n = 20) groups. The 3-y PFS rate was significantly lower in the IIS^low group than in the IIS^high group (50.0% [95% CI: 27.1-69.2%] vs. 84.2% [95% CI: 58.7-94.6%], P = .0237). Furthermore, the IIS was correlates with absolute lymphocyte counts at diagnosis (r = 0.460, P = .00355). These results suggest that the T-cell-associated immune markers could be useful to predict prognosis in RB-treated FL patients. (UMIN:000 013 795, jRCT:051 180 181).

Expression of telomerase reverse transcriptase in peripheral T-cell lymphoma

Telomere length is maintained by the activation of telomerase, which causes continuous cell division and proliferation in many carcinomas. A catalytic reverse transcriptase protein (TERT) encoded by the TERT gene plays a critical role in the activation of telomerase. We performed a molecular and pathological analysis of the TERT against three different peripheral T‐cell lymphoma (PTCL) subtypes: PTCL, not otherwise specified (PTCL‐NOS), angioimmunoblastic T‐cell lymphoma (AITL), and adult T‐cell leukemia/lymphoma (ATLL). Immunohistochemical analysis demonstrated TERT expression in 31% of AITL, 11% of PTCL‐NOS, and 5% of ATLL. Among them, AITL frequently showed high TERT expression with statistical significance. TERT promoter mutation analysis and genomic copy number evaluation were performed. TERT promoter mutation was observed in two cases of PTCL‐NOS (2/40) and not in other PTCLs. Genome copy number amplification was detected in 33% of PTCL‐NOS, 33% of AITL, and 50% of ATLL cases. We evaluated the relationship between the analyzed TERT genomic abnormalities and protein expression; however, no apparent relationship was observed. Furthermore, immunostaining showed TERT expression in the PTCL cytoplasm, suggesting the existence of mechanisms other than the maintenance of telomere length. Statistical analysis of the effect of TERT expression on the prognosis in PTCL cases revealed that TERT expression tended to have a poor prognosis in PTCL‐NOS. Since TERT expression was not an independent factor in multivariate analysis, further research will be needed to clarify the poor prognosis of PTCL‐NOS in TERT expression.

Comprehensive genetic profiling reveals frequent alterations of driver genes on the X chromosome in extranodal NK/T-cell lymphoma

Extranodal NK/T-cell lymphoma (ENKTCL) is an Epstein-Barr virus (EBV)-related neoplasm with male dominance and a poor prognosis. A better understanding of the genetic alterations and their functional roles in ENKTCL could help improve patient stratification and treatments. Here, we performed comprehensive genetic analysis of 177 ENKTCL cases to delineate the landscape of mutations, copy number alterations (CNAs), and structural variations, identifying 34 driver genes including six previously unappreciated ones, namely HLA-B, HLA-C, ROBO1, CD58, POT1, and MAP2K1. Among them, CD274 (24%) was the most frequently altered, followed by TP53 (20%), CDKN2A (19%), ARID1A (15%), HLA-A (15%), BCOR (14%), and MSN (14%). Chromosome X (chrX) losses were the most common arm-level CNAs in females (~40%), and alterations of four X-linked driver genes (MSN, BCOR, DDX3X, and KDM6A) were more frequent in males and females harboring chrX losses. Among X-linked drivers, MSN was the most recurrently altered, and its expression was lost in approximately one-third of cases using immunohistochemical analysis. Functional studies of human cell lines demonstrated that MSN disruption promoted cell proliferation and NF-κB activation. Moreover, MSN inactivation increased sensitivity to NF-κB inhibition in vitro and in vivo. In addition, recurrent deletions were observed at the origin of replication in the EBV genome (6%). Finally, by integrating the 34 drivers and 19 significant arm-level CNAs, non-negative matrix factorization and consensus clustering identified two molecular groups with different genetic features and prognosis irrespective of clinical prognostic factors. Together, these findings could help improve diagnostic and therapeutic strategies in ENKTCL.

Changes of Gastrin Levels in Autoimmune Thyroid Disorders

The relationship between thyroid disorders and gastric pathophysiology has been studied mainly from standpoints of gastric histology and gastric acid output capacity. Though anti-gastric antibody has been thought to play a part in this relationship, there have been no clear conclusions obtained about that. Since blood gastrin levels are easily measurable by radioimmunoassay today, the relationship between thyroid disorders and gastric pathophysiology has drawn attention again from a standpoint of gastrin levels. Seino et al. have reported about hypergastrinemia in hyperthyroidism, speculating that beta-adrenergic hyperresponsiveness of gastrin-producing cells could be the mechanism of hypergastrinemia. However, there are other reports which mentioned feedback mechanism between gastrin and gastric acid or interaction of gastrointestinal hormones as the main mechanism of hypergastrinemia. In this study, the problem of gastrin in Graves' disease and chronic thyroiditis were studied by measurement of fasting serum gastrin levels and gastric juice excretion in view of feedback mechanism between gastrin-producing cells and parietal cells which are the target cells of gastrin. Following results were obtained. Fasting serum gastrin levels in Graves' disease were 236.2 +/- 39.1 (mean +/- SE) pg/ml for 39 hyperthyroid patients and 126.3 +/- 23.9 pg/ml for 35 euthyroid patients. These levels were significantly higher than those of sex and age-matched control subjects with P less than 0.001 and P less than 0.05, respectively. Fasting serum gastrin levels in serial studies of 13 patients with Graves' disease were 222.3 +/- 56.7 pg/ml before treatment and 167.3 +/- 56.6 pg/ml at the time of euthyroid state after a mean observation period of 6.6 +/- 1.1 months. Fasting serum gastrin levels at the time of euthyroid state decreased significantly when compared with fasting serum gastrin levels before treatment (P less than 0.05). Fasting serum gastrin levels in chronic thyroiditis were 160.7 +/- 51.1 pg/ml for 24 hypothyroid patients and 96.4 +/- 24.7 pg/ml for 31 euthyroid patients. Each of these levels had no significant differences when compared with sex and age-matched control subjects. Fasting serum gastrin levels in serial studies of 10 patients with chronic thyroiditis were 81.1 +/- 18.0 pg/ml at the time of hypothyroid state and 91.5 +/- 15.2 pg/ml at the time of euthyroid state after a mean observation period of 7.1 +/- 2.1 months. Fasting serum gastrin levels before treatment had no significant differences when compared with fasting serum gastrin levels in euthyroid state.(ABSTRACT TRUNCATED AT 400 WORDS)