A novel rare variant R292H in RTN4R affects growth cone formation and possibly contributes to schizophrenia susceptibility

Reticulon 4 receptor (RTN4R) plays an essential role in regulating axonal regeneration and plasticity in the central nervous system through the activation of rho kinase, and is located within chromosome 22q11.2, a region that is known to be a hotspot for schizophrenia (SCZ) and autism spectrum disorder (ASD). Recently, rare variants such as copy-number variants and single-nucleotide variants have been a focus of research because of their large effect size associated with increased susceptibility to SCZ and ASD and the possibility of elucidating the pathophysiology of mental disorder through functional analysis of the discovered rare variants. To discover rare variants with large effect size and to evaluate their role in the etiopathophysiology of SCZ and ASD, we sequenced the RTN4R coding exons with a sample comprising 370 SCZ and 192 ASD patients, and association analysis using a large number of unrelated individuals (1716 SCZ, 382 ASD and 4009 controls). Through this mutation screening, we discovered four rare (minor allele frequency <1%) missense mutations (R68H, D259N, R292H and V363M) of RTN4R. Among these discovered rare mutations, R292H was found to be significantly associated with SCZ (P=0.048). Furthermore, in vitro functional assays showed that the R292H mutation affected the formation of growth cones. This study strengthens the evidence for association between rare variants within RTN4R and SCZ, and may shed light on the molecular mechanisms underlying the neurodevelopmental disorder.

Rare genetic variants in CX3CR1 and their contribution to the increased risk of schizophrenia and autism spectrum disorders

CX3CR1, a G protein-coupled receptor solely expressed by microglia in the brain, has been repeatedly reported to be associated with neurodevelopmental disorders including schizophrenia (SCZ) and autism spectrum disorders (ASD) in transcriptomic and animal studies but not in genetic studies. To address the impacts of variants in CX3CR1 on neurodevelopmental disorders, we conducted coding exon-targeted resequencing of CX3CR1 in 370 Japanese SCZ and 192 ASD patients using next-generation sequencing technology, followed by a genetic association study in a sample comprising 7054 unrelated individuals (2653 SCZ, 574 ASD and 3827 controls). We then performed in silico three-dimensional (3D) structural modeling and in vivo disruption of Akt phosphorylation to determine the impact of the detected variant on CX3CR1-dependent signal transduction. We detected a statistically significant association between the variant Ala55Thr in CX3CR1 with SCZ and ASD phenotypes (odds ratio=8.3, P=0.020). A 3D structural model indicated that Ala55Thr could destabilize the conformation of the CX3CR1 helix 8 and affect its interaction with a heterotrimeric G protein. In vitro functional analysis showed that the CX3CR1-Ala55Thr mutation inhibited cell signaling induced by fractalkine, the ligand for CX3CR1. The combined data suggested that the variant Ala55Thr in CX3CR1 might result in the disruption of CX3CR1 signaling. Our results strengthen the association between microglia-specific genes and neurodevelopmental disorders.

Hepatitis B surface antigen reduction by switching from long-term nucleoside/nucleotide analogue administration to pegylated interferon

Hepatitis B surface antigen (HBsAg) reduction during nucleoside/nucleotide analogue (NA) therapy is slow and an alternative strategy for patients receiving ongoing NA to facilitate HBsAg reduction is required. We investigated whether switching to pegylated interferon (PEG-IFN) after long-term NA administration enhances HBsAg reduction. Forty-nine patients who switched from long-term NA to 48 weeks of PEG-IFN alfa-2a were studied. The mean duration of previous NA was 48 months (sequential group). A total of 147 patients who continued NA and matched for baseline characteristics were analysed for comparison (NA continuation group). The treatment response was defined as HBsAg reduction ≥1.0 logIU/mL at the end of PEG-IFN. HBsAg reduction at week 48 was 0.81±1.1 logIU/mL in the sequential group, which was significantly higher than that in the NA continuation group (0.11±0.3 logIU/mL, P < .001). The treatment response was achieved in 29% and 2% of the sequential group and NA continuation group (P < .001), and the odds ratio of sequential therapy for the treatment response was 19 compared with the NA continuation (P < .001). In patients tested positive for hepatitis B e antigen (HBeAg), HBeAg seroconversion was higher in the sequential group (44% vs 8%, P < .001). In HBeAg-negative patients, only patients in the sequential group achieved HBsAg loss. No patient needed to resume NA administration because of HBV DNA increase accompanied by alanine aminotransferase flares. In summary, sequential therapy with PEG-IFN after long-term NA enhances the reduction of HBsAg and may represent a treatment option to promote HBsAg loss.

Asthma-like Features and Clinical Course of Chronic Obstructive Pulmonary Disease. An Analysis from the Hokkaido COPD Cohort Study

RATIONALE

Some patients with chronic obstructive pulmonary disease (COPD) have asthma-like features, such as significant bronchodilator reversibility, blood eosinophilia, and/or atopy, even if they are not clinically diagnosed as having asthma. However, the clinical significance of asthma-like features overlapping with COPD remains unclear.

OBJECTIVES

The aim of this study was to assess the effect of asthma-like features on the clinical course of patients with COPD who were adequately treated and followed-up over 10 years.

METHODS

A total of 268 patients with COPD who had been clinically considered as not having asthma by respiratory specialists were included in this study. The asthma-like features included in this study were bronchodilator reversibility (ΔFEV₁, ≥12% and ≥200 ml), blood eosinophilia (≥300 cells/μl), and atopy (positive specific IgE for any inhaled antigen). The annual changes in post-bronchodilator FEV₁ and COPD exacerbations were monitored during the first 5 years, and mortality was followed during the entire 10 years of the study.

MEASUREMENTS AND MAIN RESULTS

Fifty-seven subjects (21%) had bronchodilator reversibility, 52 (19%) had blood eosinophilia, and 67 (25%) had atopy. Subjects with blood eosinophilia had significantly slower annual post-bronchodilator FEV₁ decline; bronchodilator reversibility and atopy did not affect the annual post-bronchodilator FEV₁ decline, and none of the asthma-like features was associated with development of COPD exacerbation. Even if subjects had two or more asthma-like features, they displayed annual post-bronchodilator FEV₁ declines and exacerbation rates similar to those of subjects with one or zero asthma-like features, as well as a lower 10-year mortality rate (P = 0.02).

CONCLUSIONS

The presence of asthma-like features was associated with better clinical course in patients with COPD receiving appropriate treatment.

Graft-Versus-Host Disease Following Liver Transplantation: Development of a High-Incidence Rat Model and a Selective Prevention Method

Graft-versus-host disease (GvHD) following liver transplantation (LT) is a rare but serious complication with no presently available animal model and no preventive measures. To develop a rat model of GvHD after LT (LT-GvHD), we preconditioned hosts with sublethal irradiation plus reduction of natural killer (NK) cells with anti-CD8α mAb treatment, which invariably resulted in acute LT-GvHD. Compared with those in the peripheral counterpart, graft CD4⁺ CD25^- passenger T cells showed lower alloreactivities in mixed leukocyte culture. Immunohistology revealed that donor CD4⁺ T cells migrated and formed clusters with host dendritic cells in secondary lymphoid organs, with early expansion and subsequent accumulation in target organs. For selectively preventing GvHD, donor livers were perfused ex vivo with organ preservation media containing anti-TCRαβ mAb. T cell-depleted livers almost completely suppressed clinical GvHD such that host rats survived for >100 days. Our results showed that passenger T cells could develop typical LT-GvHD if resistant cells such as host radiosensitive cells and host radioresistant NK cells were suppressed. Selective ex vivo T cell depletion prevented LT-GvHD without affecting host immunity or graft function. This method might be applicable to clinical LT in prediagnosed high-risk donor-recipient combinations and for analyzing immunoregulatory mechanisms of the liver.

High-resolution copy number variation analysis of schizophrenia in Japan

Recent schizophrenia (SCZ) studies have reported an increased burden of de novo copy number variants (CNVs) and identified specific high-risk CNVs, although with variable phenotype expressivity. However, the pathogenesis of SCZ has not been fully elucidated. Using array comparative genomic hybridization, we performed a high-resolution genome-wide CNV analysis on a mainly (92%) Japanese population (1699 SCZ cases and 824 controls) and identified 7066 rare CNVs, 70.0% of which were small (<100 kb). Clinically significant CNVs were significantly more frequent in cases than in controls (odds ratio=3.04, P=9.3 × 10^-9, 9.0% of cases). We confirmed a significant association of X-chromosome aneuploidies with SCZ and identified 11 de novo CNVs (e.g., MBD5 deletion) in cases. In patients with clinically significant CNVs, 41.7% had a history of congenital/developmental phenotypes, and the rate of treatment resistance was significantly higher (odds ratio=2.79, P=0.0036). We found more severe clinical manifestations in patients with two clinically significant CNVs. Gene set analysis replicated previous findings (e.g., synapse, calcium signaling) and identified novel biological pathways including oxidative stress response, genomic integrity, kinase and small GTPase signaling. Furthermore, involvement of multiple SCZ candidate genes and biological pathways in the pathogenesis of SCZ was suggested in established SCZ-associated CNV loci. Our study shows the high genetic heterogeneity of SCZ and its clinical features and raises the possibility that genomic instability is involved in its pathogenesis, which may be related to the increased burden of de novo CNVs and variable expressivity of CNVs.

Abstract P4-21-14: A randomized phase II trial of trastuzumab + capecitabine versus lapatinib + capecitabine in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and taxanes: WJOG6110B/ELTOP

Background: In patients with HER2-positive metastatic breast cancer (MBC) who progressed on trastuzumab (H)-based therapy, both continuing H beyond progression and switching to lapatinib (L) in combination with chemotherapy are valid options. However, it is unclear which strategy is more effective and how we can select a proper strategy in each patient.

Methods: We conducted an open label, multicenter, randomized phase II trial to comparatively evaluate efficacy and safety of H + capecitabine (X) (HX) or L + X (LX) in women with HER2-positive MBC who were previously treated with taxanes and progressed on H-containing regimens. Patients treated with more than two chemotherapy regimens for MBC were excluded. Those treated with pertuzumab and/or T-DM1 were allowed to enroll in this study. Patients with brain metastases were also included if they are asymptomatic. Patients received H (4mg/kg loading then 2mg/kg weekly or 8mg/kg loading then 6mg/kg every 3 weeks) and X (2500 mg/m2/day on days 1-14 every 3weeks) in HX arm and L (1250 mg/day) and X (2000 mg/m2/day on days 1-14 every 3weeks) in LX arm until progression or intolerable toxicity. The primary endpoint was progression-free survival (PFS) and secondary endpoints included overall survival (OS), objective response rate (ORR), proportion of subjects progressing with brain metastases as site of first progression, and safety.We also assessed biomarkers in tumor tissues and circulating cell-free DNA.

Results: Between May 2011 and December 2014, 86 patients (43 in HX arm and 43 in LX arm) were enrolled in this study. Median age was 58 years (range 34-81), ECOG performance status was 0 (63%), 1 (35%), or 2 (2%), 63% had hormone receptor-positive disease, 15% had brain metastases, 56% had relapsed after primary surgery, and 23% had received adjuvant or neo-adjuvant trastuzumab. Median follow-up time was 44.6 months. Median PFS was 6.1 months in HX arm and 7.1 months in LX arm (hazard ratio 0.81 90% CI 0.55-1.21; p=0.39), median OS was 31.0 months in HX arm and not reached in LX arm (hazard ratio 0.58 95% CI 0.26-1.31; p=0.18), ORR was 40% in HX arm and 41% in LX arm (p=1.00), disease control rate was 73% in HX arm and 92% in LX arm (p=0.038), and proportion of subjects progressing with brain metastases as site of first progression was 5% in HX arm and 5% in LX arm. Grade 3-4 toxicities included hand-foot syndrome (21% in HX arm and 21% in LX arm) and diarrhea (9% in HX arm and 16% in LX arm). In subgroup analyses, PFS benefit in LX arm compared to HX arm was significantly larger among patients who had received previous systemic treatment for metastatic disease for less than 1 year (interaction p=0.007). Subgroup analyses by biomarkers will be presented at the meeting.

Conclusions: In women with HER2-positive MBC previously treated with trastuzumab and taxanes, lapatinib + capecitabine tended to yield better PFS and OS than trastuzumab beyond progression + capecitabine, although they were not statistically significant.Background: In patients with HER2-positive metastatic breast cancer (MBC) who progressed on trastuzumab (H)-based therapy, both continuing H beyond progression and switching to lapatinib (L) in combination with chemotherapy are valid options. However, it is unclear which strategy is more effective and how we can select a proper strategy in each patient.

Methods: We conducted an open label, multicenter, randomized phase II trial to comparatively evaluate efficacy and safety of H + capecitabine (X) (HX) or L + X (LX) in women with HER2-positive MBC who were previously treated with taxanes and progressed on H-containing regimens. Patients treated with more than two chemotherapy regimens for MBC were excluded. Those treated with pertuzumab and/or T-DM1 were allowed to enroll in this study. Patients with brain metastases were also included if they are asymptomatic. Patients received H (4mg/kg loading then 2mg/kg weekly or 8mg/kg loading then 6mg/kg every 3 weeks) and X (2500 mg/m2/day on days 1-14 every 3weeks) in HX arm and L (1250 mg/day) and X (2000 mg/m2/day on days 1-14 every 3weeks) in LX arm until progression or intolerable toxicity. The primary endpoint was progression-free survival (PFS) and secondary endpoints included overall survival (OS), objective response rate (ORR), proportion of subjects progressing with brain metastases as site of first progression, and safety.We also assessed biomarkers in tumor tissues and circulating cell-free DNA.

Results: Between May 2011 and December 2014, 86 patients (43 in HX arm and 43 in LX arm) were enrolled in this study. Median age was 58 years (range 34-81), ECOG performance status was 0 (63%), 1 (35%), or 2 (2%), 63% had hormone receptor-positive disease, 15% had brain metastases, 56% had relapsed after primary surgery, and 23% had received adjuvant or neo-adjuvant trastuzumab. Median follow-up time was 44.6 months. Median PFS was 6.1 months in HX arm and 7.1 months in LX arm (hazard ratio 0.81 90% CI 0.55-1.21; p=0.39), median OS was 31.0 months in HX arm and not reached in LX arm (hazard ratio 0.58 95% CI 0.26-1.31; p=0.18), ORR was 40% in HX arm and 41% in LX arm (p=1.00), disease control rate was 73% in HX arm and 92% in LX arm (p=0.038), and proportion of subjects progressing with brain metastases as site of first progression was 5% in HX arm and 5% in LX arm. Grade 3-4 toxicities included hand-foot syndrome (21% in HX arm and 21% in LX arm) and diarrhea (9% in HX arm and 16% in LX arm). In subgroup analyses, PFS benefit in LX arm compared to HX arm was significantly larger among patients who had received previous systemic treatment for metastatic disease for less than 1 year (interaction p=0.007). Subgroup analyses by biomarkers will be presented at the meeting.

Conclusions: In women with HER2-positive MBC previously treated with trastuzumab and taxanes, lapatinib + capecitabine tended to yield better PFS and OS than trastuzumab beyond progression + capecitabine, although they were not statistically significant.

Citation Format: Takano T, Tsurutani J, Takahashi M, Yamanaka T, Sakai K, Ito Y, Fukuoka J, Kimura H, Kawabata H, Tamura K, Matsumoto K, Aogi K, Sato K, Nishio K, Nakagawa K, Saeki T. A randomized phase II trial of trastuzumab + capecitabine versus lapatinib + capecitabine in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and taxanes: WJOG6110B/ELTOP [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-14.

Abstract P2-05-24: Prognostic value of circulating PIK3CA mutations revealed with digital PCR in patients with HER2-positive advanced breast cancer: Results of West Japan Oncology Group study 6110BTR

This abstract was withdrawn by the authors.

Distribution of Serotonergic Neurons in the Central Nervous System: A Peroxidase-Antiperoxidase Study with Anti-Serotonin Antibodies

Distribution of serotonin (5-HT) neurons in the central nervous system (CNS) of various vertebrates was investigated with a highly sensitive immunohistochemical technique. Antibodies were raised in rabbits against an antigen prepared by coupling 5-HT to bovine thyroglobulin. 5-HT neurons were found to be distributed more widely and densely than has been heretofore described. Serotonergic neuronal somata are organized according to certain basic patterns, but there are interspecific differences with regard to the distribution of 5-HT fibers. The processes of 5-HT neurons form a dense plexus by ramification and anastomosis in almost all areas of the CNS, including the ventricular surfaces. In the light of our observations, Golgi's reticular theory may have to be revised.

MR Imaging of Monostotic Fibrous Dysplasia of the Clivus

We describe the MR appearance of a case of monostotic fibrous dysplasia confined to the clivus. The lesion showed intermediate signal intensity on T2-weighted images which is uncommon among clival diseases.

Gynandroblastoma of postmenopausal women: a case report

Gynandroblastoma, an extremely rare ovarian tumour that usually consists of both Sertoli stromal cell and granulosa cell tumours, often produces both androgenic and estrogenic effects. The authors herein report a case of gynandroblastoma with the longest disease-free period reported to date. A 66-year-old woman without metrorrhagia or hirsutism presented with abdominal pain and slightly elevated serum estradiol levels. Her uterus was enlarged, and endometrial curettage performed to reduce endometrial thickness prior to laparotomy led to a diagnosis of atypical endometrial hyperplasia. She was diagnosed of ovarian tumour. The pathology report revealed that the right ovarian tumour was a "gynandroblastoma". Such lesions are classified as borderline malignant. Postoperative adjuvant therapy was not administered in this case because only a few recurrent or fatal cases have been reported. The lesion was classified as pTlaN0M0 according to Union for International Cancer Control (UICC). The patient is alive and has been disease-free for 77 months post-surgery.