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Particle beam therapy (PT) is a potentially promising approach to the treatment of extrahepatic biliary cancer (EBC) because of its unique dose distribution using the Bragg peak. However, the superiority of PT to photon radiotherapy (XT) remains unclear. Therefore, we conducted a systematic review and meta-analysis to compare PT and XT for the treatment of EBC. The primary endpoint was overall survival (OS), which was pooled using a random-effects model. Nine articles comprising a total of 1558 patients (seven XT articles, n = 1488 patients; two PT articles, n = 70 patients) were screened. In addition, we compared the outcomes of XT and PT with the outcomes available from a prospective data registry (proton-net). The 1-year OS probability rates were 55, 65 and 72% for the XT group, PT group and PT registry, respectively. The 2-year OS probability rates were 26, 38 and 38% for the XT group, PT group and PT registry, respectively. The 3-year OS probability rates were 12, 35 and 18% for the XT group, PT group and PT registry, respectively. Although the difference between the 1-year OS rates of the XT group and PT registry was statistically significant, no other significant superiority was observed among these groups. In conclusion, the efficacy of PT was not superior to that of XT during this meta-analysis., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

Background: Plexiform neurofibromas (PN) are a manifestation of neurofibromatosis type 1 (NF1) that may cause morbidity and impact health-related quality of life (HRQoL). Selumetinib (ARRY-142886, AZD6244) is an orally available, selective, mitogen-activated protein kinase kinase 1/2 inhibitor approved for children with NF1 and symptomatic, inoperable PN in regions including the USA (aged ≥2 years), EU (≥3 years), and Japan (≥3 years). This open-label, single-arm, phase I study evaluated selumetinib in Japanese children with NF1 and symptomatic, inoperable PN., Methods: Eligible patients (aged 3-18 years) received oral selumetinib (25 mg/m 2 twice daily) continuously in 28-day cycles in a fasted state. Primary objectives were safety and tolerability. Secondary objectives included pharmacokinetics, efficacy, PN-related morbidities, and HRQoL., Results: Twelve patients (median age 13.3 years) were enrolled, received ≥1 selumetinib dose (data cutoff: cycle 13 day 1) with median follow-up of 11.5 months. All patients had baseline PN-related morbidities, most commonly disfigurement (91.7%) and pain (58.3%). Most frequently reported any-grade adverse events were dermatologic and gastrointestinal. Objective response rate was 33.3%; median duration of response was not reached. Most patients (83.3%) had target PN volume reduction versus baseline. No patients reported worsening of PN-related morbidities. Selumetinib was rapidly absorbed with moderate-to-high inter-patient variability in maximum plasma concentration and area under the concentration-time curve from time 0-6 hours., Conclusions: Consistent with results of the phase II SPRINT trial, 25 mg/m 2 selumetinib twice daily was well tolerated with a manageable safety profile in Japanese children with NF1 and symptomatic, inoperable PN., Competing Interests: SS’s institution received funding from AstraZeneca and received grants from Osaka University and ARTham Therapeutics. SS has also received grants for an endowed course from OITA City (Division of General Pediatrics and Emergency Medicine). SS is also a committee member of The Japanese Society of Hematology/Oncology and the Japan Children’s Cancer Group. KT has received grants or contracts from AstraZeneca, Novartis, and Ohara. KT has received payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing, or educational events from Chugai Pharmaceutical and Bayer. KT has also received payment for participating on an advisory board or Data Safety Monitoring Board from AstraZeneca and Bayer. KT holds a leadership or fiduciary role in the Japan Children’s Cancer Group and the Japan Society for Neuro-Oncology. MA reports no conflicts of interest. TO, AW, MS, MH, and KS report employment at AstraZeneca and own stock at AstraZeneca. YN has received consulting fees from AstraZeneca and has received payment or honoraria for lectures from AstraZeneca., (© The Author(s) 2023. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Primary CNS germ cell tumors (GCTs) are rare neoplasms predominantly observed in the pediatric and young adult populations. In line with the hypothesis that the primordial germ cell is the cell-of-origin, histopathological examinations for this pathology involve a diverse range of components mirroring the embryogenic developmental dimensions. Chemotherapy and radiotherapy are the mainstays of treatment, with surgery having a limited role for diagnosis and debulking of residual tissue after treatment. While better management has been achieved over recent decades by modifying radiation coverage and selecting appropriate chemotherapy, standardization of treatment remains challenging, partly due to the low volume of cases encountered in each institution. As the incidence is higher in East Asia, including Japan, the Japan Society for Neuro-Oncology established a multidisciplinary task force to create an evidence-based guideline for CNS GCTs. This guideline provides recommendations for multiple dimensions of clinical management for CNS GCTs, with particular focus on diagnostic measures including serum markers, treatment algorithms including surgery, radiotherapy, and chemotherapy, and under-investigated but important areas such as treatment for recurrent cases, long-term follow-up protocols, and long-term sequelae. This guideline serves the purpose of helping healthcare professionals keep up to date with current knowledge and standards of management for patients with this rare disease in daily clinical practice, as well as driving future translational and clinical research by recognizing unmet needs concerning this tumor., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Cerebrospinal fluid (CSF) cytology and spinal MR imaging are routinely performed for staging before treatment of intracranial germinoma. However, the interpretation of the results of CSF cytology poses 2 unresolved clinical questions: (1) Does positive CSF cytology correlate with the presence of spinal lesion before treatment? and (2) Is craniospinal irradiation (CSI) necessary for patients with positive CSF cytology in the absence of spinal lesion?, Methods: Multicenter retrospective analyses were performed based on a questionnaire on clinical features, spinal MR imaging finding, results of CSF cytology, treatments, and outcomes which was sent to 86 neurosurgical and 35 pediatrics departments in Japan. Pretreatment frequencies of spinal lesion on MR imaging were compared between the patients with positive and negative cytology. Progression-free survival (PFS) rates were compared between patients with positive CSF cytology without spinal lesion on MR imaging treated with CSI and with whole brain or whole ventricular irradiation (non-CSI)., Results: A total of 92 germinoma patients from 45 institutes were evaluated by both CSF cytology and spinal MR images, but 26 patients were excluded because of tumor markers, the timing of CSF sampling or incomplete estimation of spinal lesion. Of the remaining 66 germinoma patients, spinal lesions were equally identified in patients with negative CSF cytology and positive cytology (4.9% and 8.0%, respectively). Eleven patients treated with non-CSI had excellent PFS comparable to 11 patients treated with CSI., Conclusion: CSI is unnecessary for germinoma patients with positive CSF cytology without spinal lesions on MR imaging., (© The Author(s) 2021. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Background: The Delphi consensus statements on the management of germ cell tumors (GCTs) failed to reach agreements on the statement that the cases with (i) pineal and neurohypophyseal bifocal lesion, (ii) with diabetes insipidus, and (iii) with negative tumor markers can be diagnosed as germinoma without histological verification. To answer this, multicenter retrospective analysis was performed., Methods: A questionnaire on clinical findings, histological diagnosis, and details of surgical procedures was sent to 86 neurosurgical and 35 pediatrics departments in Japan., Results: Fifty-one institutes reported 132 cases that fulfilled the 3 criteria. Tissue sampling was performed in 91 cases from pineal (n = 44), neurohypophyseal (n = 32), both (n = 6), and distant (n = 9) lesions. Histological diagnosis was established in 89 cases: pure germinoma or germinoma with syncytiotrophoblastic giant cells in 82 (92.1%) cases, germinoma and mature teratoma in 2 cases, and granulomatous inflammation in 2 cases. Histological diagnosis was not established in 2 cases. Although no tumors other than GCTs were identified, 3 (3.4%) patients had non-germinomatous GCTs (NGGCTs). None of the patients developed permanent complications after endoscopic or stereotactic biopsy. Thirty-nine patients underwent simultaneous procedure for acute hydrocephalus without permanent complications, and hydrocephalus was controlled in 94.9% of them., Conclusion: All patients who fulfilled the 3 criteria had GCTs or granulomatous inflammation, but not other types of tumors. However, no fewer than 3.4% of the patients had NGGCTs. Considering the safety and the effects of simultaneous procedures for acute hydrocephalus, biopsy was recommended in such patients., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: A prolonged interval between onset of symptoms and diagnosis of childhood brain tumor is associated with worse neurological outcomes. The objectives of this study are to determine factors contributing to diagnostic delay and to find an interventional focus for further reduction in the interval between symptom onset and diagnosis in Japan., Methods: We retrospectively analyzed 154 patients younger than 18 years with newly diagnosed brain tumors who visited our institution from January 2002 to March 2013., Results: The median age at diagnosis was 6.2 years and the median total diagnostic interval (TDI) was 30 days. Patients with low-grade tumors and cerebral midline tumor location had significantly long TDI. Durations between the first medical consultation and diagnosis (diagnostic interval, DI) were exceedingly longer for patients with visual, hearing, or smelling abnormalities as the first symptom (median, 303 days). TDI and DI of patients who visited ophthalmologists or otolaryngologist for the first medical consultation were significantly longer. Among these patients, longer DI was associated with worse visual outcome., Conclusion: Raising awareness of brain tumor diagnosis among ophthalmologists and otolaryngologists may reduce diagnostic delay and may improve the neurological impairment of children with brain tumors in Japan., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology and the European Association of Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study aimed to determine the maximum tolerance dose (MTD) and to estimate the recommended dose (RD) of concomitant S-1 with carbon-ion radiotherapy (RT) for sinonasal squamous cell carcinoma (SCC). Nine patients with sinonasal SCC received carbon-ion RT with escalating doses of S-1 according to phase I methods. Doses of 40, 60 and 80 mg/m2/day were administered twice daily in dose levels 1, 2 and 3, respectively, from days 1 to 14 and 22 to 35. Carbon-ion RT was administered at a dose of 70.4 Gy (relative biological effectiveness) in 32 fractions, 5 days a week. Two patients developed grade 3 acute dermatitis. However, none developed dose-limiting toxicities. Therefore, the MTD of S-1 could not be determined; the RD was estimated to be 80 mg/m2/day with concurrent carbon-ion RT. Partial response and stable disease were noted in 5 and 4 patients, respectively. The 2-year overall survival and local control rates were 56 and 74%, respectively. Overall, 2 patients developed ≥grade 3 late toxicities; among them, 1 patient developed grade 3 cataract and the other developed grade 4 cataract, optic nerve disorder and hearing impairment. To the best of our knowledge, this phase I study is the first clinical trial to evaluate concomitant S-1 with carbon-ion RT for sinonasal SCC. The MTD of S-1 could not be determined, and the RD was estimated to be 80 mg/m2/day. This study demonstrated a manageable safety profile for this combination. The observed outcomes may facilitate further evaluation of this novel therapy., (© The Author(s) 2020. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

Spontaneous necrosis is a defining feature of glioblastomas (GBMs), the most malignant glioma. Despite its strong correlations with poor prognosis, it remains unclear whether necrosis could be a possible cause or mere consequence of glioma progression. Here we isolated a particular fraction of necrotic products spontaneously arising from glioma cells, morphologically and biochemically defined as autoschizis-like products (ALPs). When administered to granulocyte macrophage colony-stimulating factor (GM-CSF)-primed bone marrow-derived macrophage/dendritic cells (Mφ/DCs), ALPs were found to be specifically engulfed by Mφs expressing a tumor-associated macrophage (TAM) marker CD204. ALPs from glioma stem cells (GSCs) had higher activity for the TAM development than those from non-GSCs. Of note, expression of the Il12b gene encoding a common subunit of IL-12/23 was upregulated in ALPs-educated Mφs. Furthermore, IL-12 protein evidently enhanced the sphere-forming activity of GBM patient-derived cells, although interestingly IL-12 is generally recognized as an antitumoral M1-Mφ marker. Finally, in silico analysis of The Cancer Genome Atlas (TCGA) transcriptome data of primary and recurrent GBMs revealed that higher expression of these IL-12 family genes was well correlated with more infiltration of M1-type TAMs and closely associated with poorer prognosis in recurrent GBMs. Our results highlight a role of necrosis in GSC-driven self-beneficial niche construction and glioma progression, providing important clues for developing new therapeutic strategies against gliomas., (©AlphaMed Press 2020.)

Cancer stem cells (CSCs) are believed to be maintained within a microenvironmental niche. Here we used polymer microarrays for the rapid and efficient identification of glioma CSC (GSC) niche mimicries and identified a urethane-based synthetic polymer, upon which two groups of niche components, namely extracellular matrices (ECMs) and iron are revealed. In cultures, side population (SP) cells, defined as GSCs in the rat C6 glioma cell line, are more efficiently sustained in the presence of their differentiated progenies expressing higher levels of ECMs and transferrin, while in xenografts, ECMs are supplied by the vascular endothelial cells (VECs), including SP cell-derived ones with distinctively greater ability to retain xenobiotics than host VECs. Iron is stored in tumor infiltrating host macrophages (Mφs), whose protumoral activity is potently enhanced by SP cell-secreted soluble factor(s). Finally, coexpression of ECM-, iron-, and Mφ-related genes is found to be predictive of glioma patients' outcome. Our polymer-based approach reveals the intrinsic capacities of GSCs, to adapt the environment to organize a self-advantageous microenvironment niche, for their maintenance and expansion, which redefines the current concept of anti-CSC niche therapy and has the potential to accelerate cancer therapy development. Stem Cells 2016;34:1151-1162., (© 2016 AlphaMed Press.)

Carbon ion therapy is a type of radiotherapy that can deliver high-dose radiation to a tumor while minimizing the dose delivered to organs at risk. Moreover, carbon ions are classified as high linear energy transfer radiation and are expected to be effective for even photon-resistant tumors. A 73-year-old man with glottic squamous cell carcinoma, T3N0M0, refused laryngectomy and received carbon ion therapy of 70 Gy (relative biological effectiveness) in 35 fractions. Three months after the therapy, the patient had an upper airway inflammation, and then laryngeal edema and pain occurred. Five months after the therapy, the airway stenosis was severe and computed tomography showed lack of the left arytenoid cartilage and exacerbation of laryngeal necrosis. Despite the treatment, 5 and a half months after the therapy, the laryngeal edema and necrosis had become even worse and the surrounding mucosa was edematous and pale. Six months after the therapy, pharyngolaryngoesophagectomy and reconstruction with free jejunal autograft were performed. The surgical specimen pathologically showed massive necrosis and no residual tumor. Three years after the carbon ion therapy, he is alive without recurrence. The first reported laryngeal squamous cell carcinoma case treated with carbon ion therapy resulted in an unexpected radiation laryngeal necrosis. Tissue damage caused by carbon ion therapy may be difficult to repair even for radioresistant cartilage; therefore, hollow organs reinforced by cartilage, such as the larynx, may be vulnerable to carbon ion therapy. Caution should be exercised when treating tumors in or adjacent to such organs with carbon ion therapy., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objective: To study the oncological outcome of the patients with unresectable locally advanced primary head and neck cancers invading the skull base, treated with particle radiotherapy., Methods: Fifty-seven patients with unresectable primary head and neck cancers invading the skull base received proton or carbon ion radiotherapy as definitive treatment at Hyogo Ion Beam Medical Center between 2003 and 2009. Forty-seven patients were treated with proton radiotherapy and 10 patients were treated with carbon ion radiotherapy. A retrospective review was performed with clinical charts and recorded imagings., Results: With a median follow-up of 32 months, the 3-year actual survival and local progression-free rates of all the patients were 61 and 56%, respectively. The 3-year actual survival rates of adenoid cystic carcinoma, squamous cell carcinoma, olfactory neuroblastoma, adenocarcinoma and malignant melanoma were 83, 44, 75, 0 and 38%, respectively. The 3-year actual local control rates of adenoid cystic carcinoma, squamous cell carcinoma, olfactory neuroblastoma, adenocarcinoma and malignant melanoma were 63, 31, 83, 50 and 0%, respectively. Distant metastasis was observed in 13 of 25 patients in adenoid cystic carcinoma, two of 14 patients in squamous cell carcinoma, one of six patients with olfactory neuroblastoma, two of four patients with adenocarcinoma, three of four patients with malignant melanoma and two of three patients with undifferentiated carcinoma. Mucositis and dermatitis were seen as acute toxicities. The most common late toxicity was visual disorder. Grades 2, 3 and 4 visual disorders were observed in seven, five and two patients, respectively., Conclusions: Proton and carbon ion radiotherapy resulted in satisfactory local control in patients with locally advanced unresectable primary head and neck cancers invading the skull base.

The purpose of this study was to evaluate the treatment outcomes of stereotactic body radiotherapy (SBRT) for Stage I small-cell lung cancer (SCLC). From April 2003 to September 2009, a total of eight patients with Stage I SCLC were treated with SBRT in our institution. In all patients, the lung tumors were proven as SCLC pathologically. The patients' ages were 58-84 years (median: 74). The T-stage of the primary tumor was T1a in two, T1b in two and T2a in four patients. Six of the patients were inoperable because of poor cardiac and/or pulmonary function, and two patients refused surgery. SBRT was given using 7-8 non-coplanar beams with 48 Gy in four fractions. Six of the eight patients received 3-4 cycles of chemotherapy using carboplatin (CBDCA) + etoposide (VP-16) or cisplatin (CDDP) + irinotecan (CPT-11). The follow-up period for all patients was 6-60 months (median: 32). Six patients were still alive without any recurrence. One patient died from this disease and one died from another disease. The overall and disease-specific survival rate at three years was 72% and 86%, respectively. There were no patients with local progression of the lesion targeted by SBRT. Only one patient had nodal recurrence in the mediastinum at 12 months after treatment. The progression-free survival rate was 71%. No Grade 2 or higher SBRT-related toxicities were observed. SBRT plus chemotherapy could be an alternative to surgery with chemotherapy for inoperable patients with Stage I small-cell lung cancer. However, further investigation is needed using a large series of patients.

Purpose: S-1 is an oral fluoropyrimidine. The purpose of this study was to review the clinical outcomes of S-1 with concurrent radiotherapy for patients with oropharyngeal cancer., Materials and Methods: Between 2002 and 2007, 38 patients with oropharyngeal cancer treated concurrently with S-1 and definitive radiotherapy were reviewed. The clinical stage was Stage I in 4 patients, Stage II in 7, Stage III in 7, and Stage IV in 20. S-1 was administered orally twice daily for 4 consecutive weeks followed by a 2-week drug withdrawal. The initial dose of S-1 was 65 mg/m(2)/day. All patients were treated using three-dimensional conformal radiotherapy with a median total dose of 65.1 Gy (range, 60.0-71.0 Gy). Clinical outcomes and major acute toxicities were analyzed based on medical records and clinical follow-up., Results: With a median follow-up time of 33 months, the 3-year estimates of local-regional control, distant metastases-free survival, disease-free survival, and overall survival for all patients were 75%, 80%, 65%, and 80%, respectively. The 3-year estimates of local-regional control according to stage were 100% for Stages I and II, 86% for Stage III, and 56% for Stage IV. The rate of ≥ Grade 3 acute mucositis was 32%, and the rate of ≥ Grade 3 hematological toxicities was 8%. No other severe toxicities were observed., Conclusions: Concurrent chemoradiotherapy with S-1 was found to be effective, especially for early disease. The treatment-related toxicities were acceptable, and the incidence of myelotoxicity was low. Further study must be carried out to compare with other chemotherapy regimens.

In this study, we evaluated the feasibility, efficacy and toxicity of concurrent chemoradiotherapy with S-1 (tegafur-gimeracil-oteracil potassium) for T2N0 glottic carcinoma. A total of 23 patients with T2N0 glottic carcinoma received chemoradiotherapy with S-1. Radiotherapy consisted of five daily fractions of 2 Gy per week, to a total median dose of 70 Gy. S-1 was administered 65 mg/m(2) per day for 4 weeks, beginning on the day therapy was started, followed by 2 weeks off the drug and twice a day until the end of radiotherapy. Initial local control rate of the primary tumor was achieved in all patients. The median follow-up period for all patients was 38 months. The 3-year local control rate was 95.4%. Regarding adverse reactions, grade 3 mucositis upon clinical examination, mucositis upon functional/symptomatic examination, dysphagia, hepatic toxicity and anemia were observed in 13, 2, 2, 1 and 1 patients, respectively. This chemoradiotherapy did not result in grade 4 acute toxicity or severe late toxicity. Chemoradiotherapy with S-1 was feasible, well tolerated and effective. This therapy is suggested as a possible regimen for improving local control of T2N0 glottic carcinoma.

Humanized NOD/Shi-scid/interleukin-2Rgamma(null) (NOG) mice with full T cell development had significantly longer life span after Epstein-Barr virus (EBV) infection, compared with those with minimal T cell development. Removing CD3(+) or CD8(+) T cells from EBV-infected humanized mice by administration of anti-CD3 or anti-CD8 antibodies reduced their life span. CD8(+) T cells obtained from EBV-infected mice suppressed the outgrowth of autologous B cells isolated from uninfected mice and inoculated with EBV in vitro. These results indicate that humanized NOG mice are capable of T cell-mediated control of EBV infection and imply their usefulness as a tool to evaluate immunotherapeutic and prophylactic strategies for EBV infection.

The functional human immune system, including T, B, and natural killer lymphocytes, is reconstituted in NOD/Shi-scid/IL-2Rgamma(null) (NOG) mice that receive hematopoietic stem cell transplants. Here, we show that these humanized mice can recapitulate key aspects of Epstein-Barr virus (EBV) infection in humans. Inoculation with approximately 1 x 10(3) TD(50) (50% transforming dose) of EBV caused B cell lymphoproliferative disorder, with histopathological findings and latent EBV gene expression remarkably similar to that in immunocompromised patients. Inoculation with a low dose of virus (

The homobasidiomycete Coprinus cinereus exhibits remarkable photomorphogenesis during fruiting-body development. Under proper light conditions, fruiting-body primordia proceed to the maturation phase in which basidia in the pileus undergo meiosis, producing sexual spores, followed by stipe elongation and pileus expansion for efficient dispersal of the spores. In the continuous darkness, however, the primordia do not proceed to the maturation phase but are etiolated: the pileus and stipe tissues at the upper part of the primordium remain rudimentary and the basal part of the primordium elongates, producing "dark stipe." In this study we genetically analyzed five strains that produce dark stipes even if light conditions promoting the maturation are given and then characterized one of them, Uar801 (dst1-1). The dst1 gene was cloned as a DNA fragment that rescues the dst1-1 mutation. Dst1 is predicted to be a protein of 1175 amino acids that contains two PAS domains, a coiled-coil structure, and a putative, glutamine-rich, transcriptional activation domain (AD). One of the PAS domains exhibits significant similarity to the LOV domains of known blue-light receptors, suggesting that Dst1 is a blue-light receptor of C. cinereus. The dst1-1 mutation is predicted to truncate the putative AD in the C-terminal region.

Protoporphyrinogen oxidase (Protox), an enzyme that catalyzes the common step of chlorophyll and heme biosynthetic pathways, was purified from spinach chloroplasts. The molecular weight of purified protein was estimated to be approximately 60,000 by SDS-PAGE. Protox activity was stimulated by addition of FAD, suggesting that chloroplast Protox requires FAD as a cofactor. Furthermore, the Protox-inhibiting herbicide, S23142, specifically inhibited the purified Protox activity at an IC50 value of 1 nM.

Splicing of mRNA precursors (pre-mRNAs) occurs in a multimolecular complex, termed spliceosome, which is comprised of pre-mRNA, small nuclear ribonucleoprotein particles (snRNPs), and other protein factors including spliceosome-associated proteins (SAPs). SAP49 is thought to be a subunit of the essential splicing factor SF3b and is involved in U2 snRNP function in mammalian cells. We have isolated a Caenorhabditis elegans cDNA encoding an RNA-binding protein with two RNA recognition motifs (RRMs) which shows extensive similarity to the human SAP49. The primary transcript for this C. elegans SAP49 homologue (cSAP49) seems to contain at least two additional cistrons and can be processed into three different mature mRNAs by trans-splicing. The cSAP49 mRNA, like other mRNAs in the same polycistronic unit, is expressed in most of the developmental stages, consistent with its putative essential function for mRNA splicing. By means of an in vitro RNA selection system, we demonstrate that cSAP49 possesses specific RNA-binding activity which resides in its second RRM.