Polycomb-group (PcG) complex 1 acts as an E3 ubiquitin ligase both for histone H2A to silence transcription and for geminin to regulate its stability. Scmh1 is a substoichiometric component of PcG complex 1 that provides the complex with an interaction domain for geminin. Scmh1 is unstable and regulated through the ubiquitin-proteasome system, but its molecular roles are unknown, so we generated Scmh1-deficient mice to elucidate its function. Loss of Scmh1 caused derepression of Hoxb4 and Hoxa9, direct targets of PcG complex 1-mediated transcriptional silencing in hematopoietic cells. Double knockdown of Hoxb4 and Hoxa9 or transduction of a dominant-negative Hoxb4N→A mutant caused geminin accumulation. Age-related transcriptional downregulation of derepressed Hoxa9 also leads to geminin accumulation. Transduction of Scmh1 lacking a geminin-binding domain restored derepressed expression of Hoxb4 and Hoxa9 but did not downregulate geminin like full-length Scmh1. Each of Hoxb4 and Hoxa9 can form a complex with Roc1-Ddb1-Cul4a to act as an E3 ubiquitin ligase for geminin. We suggest that geminin dysregulation may be restored by derepressed Hoxb4 and Hoxa9 in Scmh1-deficient mice. These findings suggest that PcG and a subset of Hox genes compose a homeostatic regulatory system for determining expression level of geminin.
As a different entity of diffuse large B-cell lymphoma (DLBCL) according to the current World Health Organization classification,1 primary mediastinal large B-cell lymphoma (PMBL) is different from DLBCL in terms of clinical, immunohistochemical and genetic features.2 Despite a remarkable advance with first-line treatment of PMBL patients in the rituximab era,3, 4, 5, 6, 7 10–30% of patients still experience progression or relapse. Although patients with relapsed or refractory PMBL are often treated with high-dose therapy followed by autologous stem cell transplantation (HDT/ASCT) after salvage treatment, the progression-free survival (PFS) at 5 years of 27% is unsatisfactory compared with DLBCL in the pre-rituximab era.8, 9, 10 Moreover, information regarding outcomes after HDT/ASCT for relapsed or refractory PMBL is limited in the rituximab era. Therefore, clarifying the current role of HDT/ASCT is vital to establish the optimal treatment strategy.
Distinguishing between central nervous system lymphoma (CNSL) and CNS infectious and/or demyelinating diseases, although clinically important, is sometimes difficult even using imaging strategies and conventional cerebrospinal fluid (CSF) analyses. To determine whether detection of genetic mutations enables differentiation between these diseases and the early detection of CNSL, we performed mutational analysis using CSF liquid biopsy technique.In this study, we extracted cell-free DNA from the CSF (CSF-cfDNA) of CNSL (N = 10), CNS infectious disease (N = 10), and demyelinating disease (N = 10) patients, and performed quantitative mutational analysis by droplet-digital PCR. Conventional analyses were also performed using peripheral blood and CSF to confirm the characteristics of each disease.Blood hemoglobin and albumin levels were significantly lower in CNSL than CNS infectious and demyelinating diseases, CSF cell counts were significantly higher in infectious diseases than CNSL and demyelinating diseases, and CSF-cfDNA concentrations were significantly higher in infectious diseases than CNSL and demyelinating diseases. Mutation analysis using CSF-cfDNA detected MYD88L265P and CD79Y196 mutations in 60% of CNSLs each, with either mutation detected in 80% of cases. Mutual existence of both mutations was identified in 40% of cases. These mutations were not detected in either infectious or demyelinating diseases, and the sensitivity and specificity of detecting either MYD88/CD79B mutations in CNSL were 80% and 100%, respectively. In the four cases biopsied, the median time from collecting CSF with the detected mutations to definitive diagnosis by conventional methods was 22.5 days (range, 18-93 days).These results suggest that mutation analysis using CSF-cfDNA might be useful for differentiating CNSL from CNS infectious/demyelinating diseases and for early detection of CNSL, even in cases where brain biopsy is difficult to perform.
Morphology of cells in the specimens on hematoxylin-eosin staining is shown. MYC expression is shown in lymph node specimens from patient 3. LPF, MPF, and HPF denote low-power, middle-power, and high-power fields, respectively. (PPTX 1063Â kb)
Cancer metastasis is the leading cause of death in patients with any type of solid cancer. To develop effective cancer treatments, it is essential to understand the molecular mechanisms underlying cancer metastasis. Previously we established peritoneal metastasis cell models derived from human scirrhous gastric cancer patients. In this article, we focus on the CELSR1 gene, which is involved in Wnt signaling but whose association with peritoneal metastasis is still unclear. We unveiled gene alterations and the prognostic relevance of the CELSR1 gene in cancer patients by analyzing public resources for cancer genomic and patient cohorts. RT-qPCR and immunoblot analyses revealed that CELSR1 expression was significantly elevated in our cell lines, which had high peritoneal metastatic property, compared with their parental cell lines, which had lower peritoneal metastatic property. Some of the gene alterations in the coding region of CELSR1 were observed in our metastatic cell lines, but they were not associated with the metastatic property or with patient prognosis. Knockdown of CELSR1 via the shRNA technique significantly decreased migration and invasion in the cell lines having high peritoneal metastatic property, whereas the knockdown did not significantly affect proliferation. These results show that CELSR1 plays an important role in peritoneal metastasis and that CELSR1 is a novel peritoneal metastasis-associated gene. The results also suggest that CELSR1 is a proper molecular target for therapy against peritoneal metastasis of scirrhous gastric cancers.
Ocular adnexal mucosa-associated lymphoid tissue-type lymphoma (OAL) is a distinct category of indolent B-cell non-Hodgkin's lymphoma.1 OAL is commonly found in clinical stage IE or IIE at diagnosis, and is associated with a favorable prognosis.2, 3, 4, 5 However, patients often require treatment because of cosmetic problems, discomfort or pain. Although local irradiation therapy has been frequently used as a treatment option for OAL, it is associated with high risks of complications, such as dry eye, cataract, decreased visual acuity, conjunctivitis, conjunctival ulcer, retinopathy, optic neuropathy and cancer.2,6, 7, 8, 9, 10 The repeated administration of rituximab, weekly four times, is an effective alternative associated with high response rates and lower risks of complications. However, a high rate of relapse has reportedly been a marked concern with this modality.2,11,12 Accordingly, an optimal treatment strategy with fewer adverse effects and sustainable efficacy is required to treat patients with OAL because such patients show a more favorable prognosis. Here, we retrospectively compared the efficacy and adverse effects of the monthly administration of rituximab with that of radiotherapy as the initial treatment for OAL. We showed that monthly rituximab may be more useful in view of the better event-free survival (EFS) and fewer adverse effects on treating patients with OAL, compared with radiotherapy and weekly infusion four times of rituximab.
Table 1 shows the characteristics of patients diagnosed with OAL in our department between 2008 and 2013. Informed consent for each treatment was obtained from all patients. Responses were assessed by whole-body computed tomography, FDG-positron emission tomography, magnetic resonance imaging and ophthalmologic tests after the completion of eight cycles of rituximab monotherapy. Ten patients with OAL received rituximab alone at 375 mg/m2 per day intravenously every 4 weeks for up to eight cycles. Alternatively, seven OAL patients received local irradiation of a single eye or both eyes as a historical control in our hospital. As shown in Table 1, the median age was 70 (36–79 years) in the group treated with rituximab alone, and 73 (43–82 years) in the group receiving irradiation. Proportions of females and CSIIE patients were not significantly different between the two groups (P=1.0 for females; P=0.33 for CSIIE by Fisher's exact test). All rituximab-treated patients (n=10) achieved and maintained complete remission during the clinical follow-up (6–29 months). There were no critical adverse events associated with the monthly infusion of rituximab. As all patients achieved complete remission and were alive during the follow-up period, EFS, defined as survival without evidence of disease progression or relapse, was calculated by Kaplan–Meier methods according to the treatment modalities.
Table 1
Characteristics of patients diagnosed with OAL
EFS with the monthly administration of rituximab was sustained for a prolonged period (Figure 1). Two of eight patients relapsed in 24–26 months after the completion of radiotherapy. All patients treated with irradiation complained of dacryoadenitis, conjunctivitis, visual acuity loss or cataract. EFS of the patients receiving irradiation and monthly rituximab monotherapy is shown in Figure 1. These results demonstrated that EFS rates with the monthly administration of rituximab and that of radiotherapy were comparable (P-value=0.37).
Figure 1
EFS with monthly administration of rituximab and radiotherapy. EFS of patients receiving irradiation and rituximab therapy is shown. Dotted and solid lines indicate EFS in patients with radiotherapy or rituximab alone, respectively.
The recent availability of rituximab has improved the EFS, progression-free survival (PFS) and overall survival of patients with B-cell non-Hodgkin's lymphoma. The frequency and severity of its side effects are non-significant during mono-treatment. Thus, rituximab is currently one of the prerequisite drugs for patients with B-cell non-Hodgkin's lymphoma, especially for the aged. It was reported that four weekly cycles of rituximab at doses of 375 mg/m2 as induction therapy were significantly effective in patients with OAL, but early recurrence was common.2,11,12 Ardeshna et al.13 reported that four weekly rituximab doses of 375 mg/m2 followed by maintenance therapy every couple of months for 2 years improved PFS compared with induction therapy alone for advanced and asymptomatic follicular lymphoma, which belongs to indolent lymphoma, in which mucosa-associated lymphoid tissue-type lymphoma is classified. Notably, it is of interest that the 2-year PFS in the rituximab induction group was equivalent to the 4-year PFS in the maintenance group, and furthermore, the 4-year PFS in the former was almost the same as the 6-year PFS in the latter,13 suggesting that the duration of exposure to even a low concentration of rituximab is more critical than its concentration. The alternative modality of radiotherapy is a promising tool for OAL, as the local control rate was reportedly extremely high (85–100%).2,6, 7, 8, 9, 10,14,15 However, the risk of distant relapse is high at 10–25% and there are frequent adverse effects, such as long-term toxicity causing cataract (30–50%), xerophthalmia (20–40%), ischemic retinopathy, optic atrophy, corneal ulceration and neovascular glaucoma, as well as immediate toxicity including conjunctivitis, conjunctival ulcer and dry eyes.2,6, 7, 8, 9, 10,14,15 Patients with OAL receiving local irradiation also suffer from dry eye, cataract and conjunctivitis based on our experience. As OAL is associated with quite a favorable prognosis, therapeutic options that preserve the quality-of-life of patients with less adverse effects are chosen. Thus, we decided on the monthly administration of rituximab and obtained desirable results regarding the efficacy, EFS and reduced adverse effects in patients receiving monthly rituximab treatment. Another intriguing phenomenon is that the efficacy of rituximab may vary depending on the treatment schedule. Manipulation of the increased number of effector cells, such as NK cells and monocytes expressing Fcγ receptor, which binds to the Fc of rituximab, might be useful for patients with B-cell non-Hodgkin's lymphoma cells regarding the efficacy of rituximab. Taken together, our treatment modality may provide a more beneficial treatment outcome with less adverse effect.
Lymphomatoid granulomatosis (LyG) is a rare, B-cell derived, lymphoproliferative disorder that often presents as pulmonary nodular lesions with a histopathology of lymphatic invasion of the vascular wall. The development of LyG may be associated with reactivation of the Epstein-Barr virus under an immunosuppressive state. We herein report a case of Grade 3 LyG that developed during methotrexate therapy for rheumatoid arthritis and regressed following the withdrawal of the drug.
