GEN-13 PAIRED MUTATIONAL ANALYSIS IN SECONDARY NERVOUS SYSTEM LYMPHOMA AND PCNSL SYSTEMIC RELAPSE REVEALS DRIVER MUTATION CANDIDATES IN THE CENTRAL NERVOUS SYSTEM

Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma confined to the brain, eyes, and the spinal cord. The mechanism of central nervous system (CNS) tropism in PCNSL has not been fully elucidated. Diffuse large B cell lymphomas (DLBCLs) occasionally present with distant recurrence, which can involve inside and outside the CNS. Secondary central nervous system lymphomas (SCNSLs) are CNS relapse of systemic lymphoma. PCNSLs also rarely present with systemic relapse. We have previously reported in our study of whole exome sequencing that PCNSLs harbor frequent mutations in genes of B cell receptor pathway members and aberrant somatic hypermutation (aSHM) target genes. Although several genetic alterations were identified as more frequent in PCNSLs compared with systemic lymphomas, specific genetic alterations which serve as the driver for CNS tropism in PCNSLs has not been identified. In order to search for mutations which might serve as driver mutations in the CNS, we have performed targeted sequencing in paired samples from patients with recurrent lymphomas, either SCNSLs or PCNSL systemic relapses, using Ion Torrent multiplex PCR. Mutational profiles were compared between the primary and recurrent tumor. Six cases (four SCNSL cases and two PCNSL systemic relapse cases) were analyzed. Of note, in the SCNSL cases, several de novo mutations were enriched only among the recurrent CNS tumors. Among these mutations, BTG2 mutations were observed in 3/4 (75%), and B2M and KLHL14 mutations were observed in 2/4 (50%) cases. In the two PCNSL systemic relapse cases, KMT2D mutations were enriched only in the recurrent systemic tumors. It is suggested that these de novo mutations in the recurrent CNS tumors might serve as driver mutations in the CNS. Further analysis in larger cohorts, and functional studies are required in order to validate these findings.

NQPC-21 QOL EVALUATION IN THE TREATMENT COURSE OF CNS LYMPHOMA

Background

Primary central nervous system lymphoma (PCNSL) is the second common primary malignant brain tumor. Compared to glioma, the treatment period is often longer, but there have been few research reports on QOL evaluation during the treatment yet. In this study, we retrospectively examined the QOL scores obtained during and following treatment of PCNSL to determine the association between changes in the QOL score and response to treatment, with particular interest in the issue in the evaluation over time.

Methods

Patients with newly-diagnosed PCNSL who were treated and evaluated for QOL by EORTC QLQ-C30/BN-20 at our facility since April 2016 were included.

Results

A total of 69 patients were included, with a median age of 69, and a male to female ratio of 41:32. The median KPS was 70, and the median MMSE score was 29 points, indicating that a majority of the patients who could undergo the testing retained adequate cognitive function. There were 38 patients (55.1%) who maintained CR during the QOL evaluation period, and their QOL function scores tended to be maintained above the baseline. In contrast, 31 patients (44.9%) who relapsed during the QOL evaluation period showed a tendency to decline in global health at the time of recurrence or evaluation immediately before recurrence, with the worsened symptom score reflecting the localization of recurrence. Any associations of changes in QOL score with therapeutic methods were identified. Changes in QOL scores were rather frequently observed with exacerbation of comorbidities, perhaps due to a high incidence of PCNSL in the elderly patients.

Conclusions

EORTC QLQ-C30/BN-20 enabled QOL evaluation that might reflect treatment effect in PCNSL. The reporting rate to the questionnaire was low in patients with substantial brain dysfunction, and QOL evaluation may also be affected by comorbidities. Further investigation of influencing factors on QOL evaluation is warranted.

ACT-15 EFFICACY AND SAFETY OF SUBTOTAL RESECTION, 'FLAIRECTOMY' FOR RECURRENT GLIOBLASTOMA

Background

Aggressive resection of recurrent glioblastoma has been reported to prolong survival and should be considered for resectable recurrences. In recent years, expanded resection for primary glioblastoma, especially removal of the FLAIR hyperintensity region beyond the contrast-enhancing lesion (FLAIRectomy; FR), has been reported, but there are no reports of FR for recurrent glioblastomas. In this study, we examined the efficacy and safety of FR for recurrent glioblastoma.

Methods

Recurrent glioblastoma operated on at our institution from January 2014 to July 2022 were included. The extent of resection (EOR) of contrast-enhancing lesions and FLAIR hyperintensity lesion was measured. Progression-free survival (PFS), overall survival (OS), surgical morbidity, KPS, and MMSE were analyzed retrospectively. Removal of at least 20% of the FLAIR hyperintensity lesion was defined as FR.

Results

Thirty-five surgeries in 28 patients (age at surgery 15-81 years; median 54 years, male 20/female 15) were included. The EOR of the contrast-enhancing lesion was 96.6± 7.4%, with GTR in 28 cases and non-GTR in 7. The EOR of the lesion with FLAIR hyperintensity was 33.2±36.5% and FR was achieved in 15 cases (42.9%). The median preoperative KPS was 90 (50-100; mean 83.3 ) in the FR group and 80 (60-100; mean 81) in the non-FR group. Both PFS and OS from surgery at recurrence were significantly prolonged in the FR group (median PFS; 8.1 months vs. 4.6 months, p=0.032, median OS; 36.1 months vs. 15.9 months, p=0.009); there was no difference in PFS or OS between the GTR and non-GTR groups (p=0.33, 0.79). There were significantly fewer patients in the FR group having a decrease in KPS of 20 or more at 30/90 days postoperatively (p=0.037, 0.020).

Conclusion

In our retrospective analysis, FR prolongs PFS and OS without decreasing KPS for resectable recurrent glioblastoma. Further validation in prospective studies is warranted.

BIOM-27. PROGNOSTIC SIGNIFICANCE OF EXTENT OF RESECTION IN GLIOMA ACCORDING TO THE 2021 WHO CLASSIFICATION

BACKGROUND

In the updated 2021 WHO classification, diffuse gliomas were strictly reclassified by molecular statuses. In glioblastoma (GBM), the prognostic significance of the resection has been shown, but the excision rate to be achieved in the new classification has not been defined. Moreover, the correlation between the extent of resection (EOR) and the prognosis is still controversial for other gliomas.

METHODS

IDH 1/2 mutations and TERT promoter mutations were analyzed by Sanger sequencing, 1p/19q co-deletion by microsatellite or MLPA, and EGFR amplification and CDKN2A deletions by MLPA. The correlation between the resection rate and prognosis of each tumor type in the 2021/2016 WHO classification was analyzed retrospectively.

RESULTS

According to the 2021 classification, 293 patients with GBM, IDH-wild type, 68 with astrocytoma, IDH-mutant (2/3/4 22/26/20), and 58 with oligodendroglioma, IDH-mutant and 1p/19q co-deleted were identified. Based on the 2016 classification, they were diagnosed as 314 GBM, 106 astrocytoma (Gd II/III 37/69), and 59 oligodendroglioma. For GBM, IDH-wild type (2021 classification), a prolonged OS benefit was observed with >25% removal (p=0.042), whereas, more than 20% of tumor removal for patients with GBM (2016 classification) resulted in OS prolongation. EOR was a significant favorable prognostic factor for grade II/III astrocytoma by the 2016 classification, but not for astrocytoma, IDH-mutant (grade 2/3) in the 2021 classification. When analyzed only in patients with astrocytoma, IDH-mutant by the 2021 classification, EOR was not significantly prognostic, suggesting that poorer prognosis of patients with unresectable IDH-wild type astrocytomas (2016 classification) might have a negative impact on the outcome.

CONCLUSION

There was a strong correlation between EOR and prognosis in patients with GBM, and >25% removal was considered significant according to the 2021 classification. For astrocytoma in the 2021 classification, EOR did not show a prognostic significance, but further validation including grading effect is warranted.

ML-12 Clinical impact and management of skin-related disorders during treatment of relapsed PCNSL by tirabrutinib

BACKGROUNDS: Tirabrutinib is a second-generation Bruton’s tyrosine kinase (BTK) inhibitor, approved by the Japanese Pharmaceutical and Medical Devices Agency (PMDA) for relapsed and refractory PCNSL in March 2020. Skin-related disorder (SRD)s are the most prevalent adverse events in tirabrutinib, which accounted for 54.5% in a phase I/II trial. While the use of tirabrutinib is increasingly considered in clinical practice, the prevalence and clinical impact of tirabrutinib-related SRDs in real-world practice remains unclear. METHODS: Relapsed PCNSL patients treated with tirabrutinib at the author’s institution were identified, and divided into those with SRDs (SRD group), and without SRDs (non-SRD group). Response rate and progression-free survival (PFS) were retrospectively analyzed and compared between the two groups. RESULTS: Eleven patients were identified (median age: 73 [range: 50–83], median KPS: 70 [range: 40–90]), which included six (54.5%) from the SRD group and five (45.5%) from the non-SRD group. Response rate was 100% in the SRD group and 60% in the non-SRD group. Median PFS was 2.8 months in the SRD group and 36.3 months in the non-SRD group, which yielded no significant difference (p=0.446). While antihistamine prophylaxis using fexofenadine was performed in seven patients, among them SRDs were observed in three (27.3%). SRDs lead to tirabrutinib interruption (for seven days or more) in two (18.2%), dose reduction in three (27.3%), and discontinuation in two (18.2%) patients. Four patients in whom tirabrutinib was interrupted or discontinued due to SRDs had shorter PFS, compared with the two patients from the SRD group in whom tirabrutinib was continued (median PFS: 2.3 and 29.6 months, respectively) (p=0.049). CONCLUSIONS: SRDs substantially lead to tirabrutinib interruption or discontinuation, which could result in early PD. Since fexofenadine prophylaxis seems ineffective for preventing SRDs, other antihistamines should be considered. Establishment of the optimal management of tirabrutinib-related SRDs is warranted.

ML-18 High-dose chemotherapy supported by autologous stem cell transplant in relapsed and refractory primary CNS lymphoma

While whole brain radiation therapy (WBRT) has been performed as consolidation therapy in primary central nervous system lymphoma (PCNSL), high-dose chemotherapy supported by autologous stem cell transplant (HDC/ASCT) is widely investigated today as an alternative treatment strategy, given the high risk for radiation-induced neurotoxicity in WBRT. Various conditioning regimens have been investigated in phase II trials, which report non-inferiority of HDC/ASCT in efficacy and preservation of neurocognitive function in comparison with WBRT. Besides its promising efficacy, treatment-related deaths are reported in 11% in patients treated by a conditioning regimen using thiotepa, busulfan and cyclophosphamide (TBC), which raises a concern for safety. Among several conditioning regimens, analysis using registry data of Japan Society for Hematopoietic Cell Transplantation has revealed that the use of conditioning regimens containing thiotepa was a positive factor for longer PFS. According to the result of a phase I trial in Japan which investigated HDC/ASCT using thiotepa and busulfan (BuTT), thiotepa was approved by the pharmaceuticals and medical devices agency (PMDA) on March 2020. In comparison with the TBC regimen, cyclophosphamide is omitted, and the dose of thiotepa is lower (250 mg/m², 3 days in TBC; 5 mg/kg, 2 days in BuTT) in BuTT, therefore BuTT could be less toxic in comparison with TBC, and no treatment-related deaths were observed in the phase I study in Japan. Further investigation on the efficacy and safety of BuTT in actual clinical practice is warranted. We have constituted a multi-disciplinary team in our institution in order to perform HDC/ASCT using BuTT in relapsed/refractory PCNSL. Treatment indications are as follows; 65 years old or younger, previously treated by rituximab, methotrexate, procarbazine and vincristine (R-MPV), good organ function and neurological status. Future directions along with preliminary treatment results will be discussed at the meeting.

NQPC-5 Does high-dose methotrexate-based chemotherapy for relapsed primary CNS lymphoma increase a risk of leukoencephalopathy with prior whole brain radiotherapy?

Backgrounds: Standard care for primary central nervous system lymphoma (PCNSL) comprises high-dose (HD) methotrexate (MTX) -based chemotherapy with or without consolidation whole brain radiotherapy (WBRT). HD-MTX administration following WBRT has been suggested to increase a risk of leukoencephalopathy. However, given that there are no other agents with efficacy similar to or better than MTX, patients with relapsed PCNSL may often be treated with regimens containing HD-MTX if the initial MTX treatment achieved a long-term complete remission. Here, we retrospectively analyzed prevalence and an extent of white mater damages in association with prior WBRT in patients with relapsed PCNSL treated with HD-MTX based therapy. Patients & methods: Among 79 patients with relapsed/refractory PCNSL in a total of 162 patients with newly-diagnosed PCNSL treated in our institution from April, 2000 to February, 2021, 35 patients were identified with evaluable KPS, MMSE, and Fazekas scale data at both baseline and follow-up periods. Of the 35 patients, 22 were treated with chemotherapy at a relapse (10 with prior WBRT, while 12 without WBRT), and were included in this preliminary study. Results: In the WBRT group (male/female: 5/5), median age was 65 years (range, 45–73), initial median KPS was 70 (40–90), and median WBRT dose was 27 Gy (23.4–40). Median progression-free survival (mPFS) was 11.8 months, and median overall survival (mOS) was not reached. In the non-WBRT group (M/F 8/4), median age 75 (62–84), initial mKPS 80 (50–90), mPFS 16.2 m, and mOS not reached. Initial KPS and MMSE score tended to be worse in WBRT group, presumably due to enrichment of patients with poorer performance status and more comorbidities. A decline in the Fazekas score was not associated with MMSE deterioration.Conclusions: The preliminary analysis was not informative enough, and further extensive imaging analysis will be exploited.

Liquid biopsy of cerebrospinal fluid for MYD88 L265P mutation is useful for diagnosis of central nervous system lymphoma

The current standard of diagnosing central nervous system (CNS) lymphoma is stereotactic biopsy, however the procedure has a risk of surgical complication. Liquid biopsy of the CSF is a less invasive, non-surgical method that can be used for diagnosing CNS lymphoma. In this study, we established a clinically applicable protocol for determining mutations in MYD88 in the CSF of patients with CNS lymphoma. CSF was collected prior to the start of chemotherapy from 42 patients with CNS lymphoma and matched tumor specimens. Mutations in MYD88 in 33 tumor samples were identified using pyrosequencing. Using 10 ng each of cellular DNA and cell-free DNA (cfDNA) extracted from the CSF, the MYD88 L265P mutation was detected using digital PCR. The conditions to judge mutation were rigorously determined. The median Target/Total value of cases with MYD88 mutations in the tumors was 5.1% in cellular DNA and 22.0% in cfDNA. The criteria to judge mutation were then determined, with a Target/Total value of 0.25% as the cutoff. When MYD88 mutations were determined based on these criteria, the sensitivity and specificity were 92.2% and 100%, respectively, with cellular DNA; and the sensitivity and specificity were 100% with cfDNA. Therefore, the DNA yield, mutated allele fraction, and accuracy were significantly higher in cfDNA compared with that in cellular DNA. Taken together, this study highlights the importance of detecting the MYD88 L265P mutation in cfDNA of the CSF for diagnosing CNS lymphoma using digital PCR, a highly accurate and clinically applicable method.

Tumor Cells Detected in Retrieved Thrombus: Cancer-associated Stroke

A 51-year-old man with a history of renal cell carcinoma presented with sudden aphasia, right hemiparesis, and dysesthesia. MRA showed left middle cerebral artery occlusion, and he was diagnosed with acute ischemic stroke and treated with intravenous recombinant tissue plasminogen activator and endovascular thrombectomy. The pathological diagnosis of the retrieved thrombus was consistent with the already-known pathological findings of the primary renal cell carcinoma. Therefore, a diagnosis of cerebral embolism caused by tumor cells was made. The pathological findings of the retrieved thrombi were important in determining the cause of ischemic stroke.

GCT-34. ELUCIDATION OF THE MECHANISMS OF TUMORIGENESIS IN INTRACRANIAL GERM CELL TUMOR BY WHOLE GENOME SEQUENCE

Intracranial germ cell tumors (iGCT) are heterogenous group of primary brain tumors that consist of various subtype, and driver genetic alterations in iGCTs remain largely unknown. We have previously reported in a study of whole exome sequence that iGCTs frequently harbored mutations in the KIT gene and its downstream MAPK/PI3K pathway, regardless of tumor subtype. However, no mutations were detected in about one-quarter of germinomas and half of non-germinomatous germ cell tumors. A genome-wide methylation profiling revealed that only germinomas exhibited extreme DNA hypomethylation among iGCTs. Moreover, in mixed iGCT tumors which contained more than one tumor subtypes, each component exhibited distinct methylation status depending on the subtype, while they shared the same mutations. These data suggested that not only mutations in the coding region as previously reported, but also genetic alterations in regulatory regions including promoters and enhancers as well as non-coding RNA genes may be involved in the tumorigenesis of iGCTs. In order to comprehensively search for driver gene alterations, we performed whole genome sequence in 18 paired tumor blood samples from iGCT tumors (16germinomas and two yolk sac tumors (YST)) registered in the Intracranial Germ Cell Tumor Genome Analysis Consortium. In a preliminary analysis of four cases, YSTs harbored a significantly higher number of structural abnormalities, compared with germinomas. Of note, 62 structural abnormalities were clustered within the small genomic region of 95Mb at 1q21-44 in one YST case, suggesting a possibility of chromothripsis. A full analysis of somatic alterations is underway and will be reported.

ML-02 Chemotherapy for patients with relapsed or refractory primary CNS lymphoma

BACKGROUNDS: Standard of care for patients with primary CNS lymphoma (PCNSL) has been high-dose methotrexate (HD-MTX)-based multiagent immunochemotherapy, particularly with R-MPV-A with or without whole-brain radiotherapy (WBRT), however, the optimal treatment for relapsed/refractory (r/r)PCNSL has not been established yet. Approval of a second-generation BTK inhibitor, tirabrutinib, for r/rPCNSL in Japan in March 2020, prompted us to evaluate retrospectively efficacy of R-MPV-A for r/rPCNSL to compare their activities. PATIENTS: Histologically proven PCNSL patients treated at relapse in our institution from April 2000 to November 2019 were analyzed. Outcomes were compared between those treated with RMPVA or other regimens. RESULTS: Among 148 PCNSL patients identified, 73 had at least one relapse, of whom 47 received salvage chemotherapy including 23 treated with RMPVA, 14 with HD-MTX monotherapy, and 11 with DeVIC (DEX, etoposide, ifosfamide, CDBCA). Median age/KPS were 69 yo (20–87)/ 80 (40–100), 27 patients had received prior WBRT. RMPVA was given at the first relapse in 11 patients, median number of RMPV cycles was 8 (1–4 cycles: 10; 8 cycles 13). CR/CRu were achieved in 19 (83%), response rate was 87%, while there were two PDs (9%). After median follow-up of 21.9 months, the median PFS after salvage RMPVA was 13.0 m (95%CI: 9.1–16.9), 1-year overall survival (OS) was 82%, median OS was 70.0 m (95%CI: 12.9–127.1), which were longer than those in 24 patients with salvage treatment other than RMPVA (mPFS 4.4 m, P=0.054; mOS 13.6 m, P=0.009). Median PFS and OS for HD-MTX monotherapy were 5.1m and 36.6 m, while those for DeVIC were 4.4 m and 9.1 m, respectively. Treatment was generally well-tolerated but there was one treatment-related death. CONCLUSIONS: Salvage RMPVA at relapses was active and associated with longer survival compared with other regimens, necessitating further development of salvage regimens incorporating tirabrutinib in the future studies.

ML-21 Tirabrutinib monotherapy for relapsed/refractory primary central nervous system lymphoma

Backgrounds & purpose: Prognosis of patients with primary central nervous system lymphoma (PCNSL) remains poor despite multiagent immunochemotherapy, and standard of care for relapsed or refractory (r/r) PCNSL has not been established. Recent progresses on molecular genetics and biology of PCNSL have led to development of novel molecular targeted therapies, especially targeting Bruton’s tyrosine kinase (BTK), located in the B-cell receptor and Toll-like receptor signaling pathways. Tirabrutinb, a second generation BTK inhibitor, was approved for r/rPCNSL in March 2020 in Japan. Methods: Patients with r/rPCNSL treated with tirabrutinib since December 2017 were eligible for this retrospective study. Tirabrutinib was given orally at doses 320–480 mg/day daily until progression or unacceptable toxicity. Results: A total of 7 patients were enrolled (6 relapses, 1 refractory), 4 males, median age was 73 (range, 54–80 years), and median KPS was 70 (70–90). Three patients had received prior whole brain radiotherapy. Median number of prior therapies was 1 (1–2). Best overall response rate was 57.1%; 42.9% with a complete response (CR/CRu), 14.3% with a partial response (PR), while there were 3 PDs (42.9%). Four patients experienced PD and estimated median progression-free survival (mPFS) was 29.6 months. All patients were alive at the data cutoff with median follow up of 21.4 months (2–30.4). Common adverse events (AEs) include grade 4 neutropenia (n=1), grade 3 lymphopenia (n=3), and hepatic dysfunction (n=1). Toxic rash was observed in four patients (grade 3 in one, grade 2 in three) leading to discontinuation of tirabrutinib in two patients, while others continued on TIR with dose reduction and steroid use. The median time to rash presentation was 28 days (12–28). Conclusions: Tirabrutinib was well tolerated with frequent minor to moderate skin rash emerging within one month and active for r/rPCNSL. Long-term efficacy and safety profile need to be determined with a larger cohort.

ML-08 Safety and efficacy of consolidation cytarabine for newly-diagnosed primary central nervous system lymphoma

Backgrounds: While consolidation therapies which incorporate whole brain radiotherapy (WBRT) and/ or chemotherapies such as high dose (HD)- cytarabine are commonly applied following induction chemotherapies in primary central nervous system lymphoma (PCNSL), the optimal treatment for consolidation therapy has not been established. We aimed to investigate the safety and efficacy of consolidation cytarabine with a dose modification policy in PCNSL. Patients and methods: PCNSL patients initially treated by R-MPV (rituximab, methotrexate, procarbazine and vincristine) and subsequently treated either by WBRT of 24Gy followed by cytarabine (WBRT-AraC group), or cytarabine alone (AraC group) were identified. WBRT was deferred in patients 71 years old or younger who had obtained a complete response (CR) after R-MPV. Cytarabine was dose-modified according to age groups (3 g/m2 in patients 70 years old or younger, 2 g/m2 in patients aged 71–75 years, 1 g/m2 in patients aged 76–80 years). Toxicity profiles, progression-free survival (PFS), overall survival (OS) were analyzed. Results: Twenty-five patients were identified (median age: 69 [range: 34–80], median KPS:70 [range: 40–90]), including 11 patients from the WBRT-AraC group, and 14 patients from the AraC group. Median PFS was unreached in the WBRT-AraC group, and 41.8 months in the AraC group. Median OS was unreached in both groups. The overall rate of grade 3/4 hematologic toxicities was high (92%), but mostly manageable without major complications. Fourteen patients received 3 g/m2, 4 patients received 2 g/m2, 7 patients received 1 g/m2 of cytarabine, and the rate of grade 4 leukopenia/ thrombocytopenia was 64%/57%, 25%/50%, and 29%/29%, respectively. Discussion: HD-cytarabine consolidation therapy with dose modification according to age groups for PCNSL was feasible and well-tolerated in patients 80 years of age or younger. The efficacy of HD-cytarabine was undetermined and further investigation is warranted.

ML-06 Diagnostic value of liquid biopsy for CNS lymphoma by detection of specific gene mutations in the cerebrospinal fluid

Backgrounds & Purpose: Central nervous system lymphoma (CNSL) is the second most common primary malignant brain tumor. Brain biopsy is indispensable to confirm the diagnosis of CNSL, but has a potential risk of inducing hemorrhagic complications in the brain. Therefore, liquid biopsy using the cerebrospinal fluid (CSF) has attracted an attention as a less invasive diagnostic method. In this study, we established a digital PCR-based method to detect MYD88 mutations in CSF and evaluated its efficacy. Methods: Matched CSF and biopsy samples from CNSL patients collected before the start of chemotherapy were used. Cellular DNA and cell free DNA (cfDNA) of CSF were separately extracted from the pellet and the supernatant fraction of CSF, respectively. Presence of the MYD88 L265P mutation was examined in each fraction by the digital PCR. The mutational status obtained by liquid biopsy was compared with that of the matched biopsy specimen examined by pyrosequencing. Result: A total of 36 paired samples were used. When the cutoff value of Target/Total ratio was 0.25%, sensitivity, specificity, and area under the curve (AUC) of the digital PCR detection using cellular DNA were 92.9%, 100%, and 0.95, respectively, while they were 100%, 100%, and 1.00 using cfDNA. Conclusion: We showed that the digital PCR method was highly sensitive and specific in detecting MYD88 mutations in the CSF. We propose that CSF liquid biopsy may serve a clinically applicable surrogate to make a diagnosis of CNSL.

CTNI-65. COMBINED RITUXIMAB, METHOTREXATE, PROCARBAZINE, VINCRISTINE, AND CYTARABINE (R-MPV-A) TREATMENT FOR PATIENTS WITH RELAPSED PRIMARY CNS LYMPHOMA

BACKGROUNDS

Standard of care for patients with primary CNS lymphoma (PCNSL) has been high-dose methotrexate (HD-MTX)-based multiagent immunochemotherapy including an induction R-MPV with consolidation whole-brain radiotherapy (WBRT) and HD-cytarabine to achieve complete remission, however, the optimal treatment for relapsed/refractory (r/r) PCNSL has not been established yet, besides the recent approval of a BTK inhibitor, tirabrutinib, in Japan. We evaluated retrospectively efficacy of R-MPV-A for r/rPCNSL.

PATIENTS

Histologically proven PCNSL patients treated at relapse in our institution from April 2000 to November 2019 were analyzed. Outcomes were compared between those treated with RMPVA or other regimens.

RESULTS

Among 148 PCNSL patients identified, 73 had at least one relapse, of whom 47 received salvage chemotherapy including 23 treated with RMPVA either at the first relapse (11) or at the second or later relapse (12). Median age/KPS of this salvage RMPVA group were 71 (42–87)/80 (40–100). Nine patients were pretreated with the first-line RMPVA. HD-cytarabine was given to 13 patients. Median number of RMPV cycles was 8 (1–4 cycles: 10; 8 cycles 13). CR/CRu were achieved in 19 (83%), response rate was 87%, while there were two PDs (9%). After median follow-up of 21.9 months, the median PFS after salvage RMPVA was 13.0 m (95%CI: 9.1–16.9), 1-year overall survival (OS) was 82%, median OS was 70.0 m (95%CI: 12.9–127.1), which were longer than those in 24 patients with salvage treatment other than RMPVA (mPFS 4.4 m, P=0.054; mOS 13.6 m, P=0.009). Among patients with salvage RMPVA, HD-cytarabine was associated with better PFS (P=0.066), and complete responses were significantly correlated with longer OS. Treatment was generally well-tolerated but there was one treatment-related death.

CONCLUSIONS

Salvage RMPVA at relapses was active and associated with longer survival compared with other regimens, necessitating further development of salvage regimens incorporating tirabrutinib in the future studies.

The features and trends of out-of-hospital cardiac arrests in Japanese working generation: long-term aspects of a prospective, nationwide, population-based registry

Background

Despite sudden cardiac death (SCD) in working generation is a crucial issue in terms of public health, social and economic significance, the long-term SCD condition in working generation is unclear.

Purpose

This study aimed to clarify the features and long-term trends of SCD in working generation from 2005 through 2016 in Japan, using a prospective, nationwide, population based out-of-hospital cardiac arrest (OHCA) registry.

Methods

We performed data analysis of the nation-wide registry in Japan who experienced OHCA during the 12 years. Working generation was defined as 20 to 69 years and we analyzed only definitive cardiogenic OHCA as an approximation of SCD.

Results

The number of definitive cardiogenic OHCA of working generation during the period was 66,214 and 31% of the events in whole population was working generation. Definitive cardiogenic OHCA in working generation in terms of both number and percentage of the population had been decreased from 6522 (0.07‰) in 2005 to 4910 (0.06‰) in 2016, bystander cardiopulmonary resuscitation (CPR) and usage of automated external defibrillator (AED) ratio increased from 32.7% in 2005 to 49.6% in 2016, and 0.3% in 2005 to 14.7% in 2016 respectively, and the survival rate after one-month improved year by year, from 12.8% in 2005 to 34.0% in 2016 (picture below). Among non-medical bystanders, CPR was most often performed by colleagues in this generation, while AED use rate by colleague was smaller, and the time from witness to initial defibrillation was significantly longer than by passerby. Good prognosis was observed in terms of one-month survival ratio and neurological outcome for those undergoing CPR by colleague and passerby compared with other bystanders. For 12 years, although the degree varies, all non-medical bystander had same tendency; bystander CPR and usage of AED ratio increased, and the survival rate after one-month and neurological outcome improved year by year.

Conclusions

Not only the number but the incidence of cardiogenic OHCA in working generation has been decreased in Japan. The positive prognosis of this generation may be related to CPR by colleagues.

Figure 1. OHCA number & 1-month survival rate

Funding Acknowledgement

Type of funding source: None

Consecutive single-institution case series of primary central nervous system lymphoma treated by R-MPV or high-dose methotrexate monotherapy

OBJECTIVE

The optimal regimen for use of high dose-methotrexate-based chemotherapy in primary central nervous system lymphoma is still under debate. We conducted a retrospective study to evaluate the treatment outcome of a combination immunochemotherapy consisting of rituximab, methotrexate, procarbazine and vincristine followed by with or without whole brain radiotherapy and consolidation cytarabine, in comparison with high dose-methotrexate monotherapy followed by full dose whole brain radiotherapy.

METHODS

Newly diagnosed primary central nervous system lymphoma patients treated with either rituximab, methotrexate, procarbazine and vincristine or high dose-methotrexate in Kyorin University Hospital were identified, and the response rates and survival were compared. Toxicities, post-treatment transition of Mini-Mental State Examination, Karnofsky performance status score, Fazekas scale and prognostic factors were analysed in the rituximab, methotrexate, procarbazine and vincristine group.

RESULTS

Ninety-five patients treated with rituximab, methotrexate, procarbazine and vincristine (n = 39) or high dose-methotrexate (n = 56) were analysed. The complete response/complete response unconfirmed rate was significantly higher in the rituximab, methotrexate, procarbazine and vincristine group (74.4 vs. 15.4%, P < 0.001). Accordingly, both median progression-free survival and overall survival were significantly longer in the rituximab, methotrexate, procarbazine and vincristine group (median progression-free survival: unreached vs. 14.75 months, P < 0.001) (median overall survival: unreached vs. 63.15 months, P = 0.005). Although the rate of grade 3/4 hematologic toxicities was high both during rituximab, methotrexate, procarbazine and vincristine and consolidation cytarabine, the rate of grade 3/4 infections was low, and no treatment related deaths were observed. Deterioration in Karnofsky performance status or Mini-Mental State Examination was rare, except on disease recurrence. Although whole brain radiotherapy was associated with Fazekas scale deterioration, its association with Karnofsky performance status or Mini-Mental State Examination deterioration was not significant.

CONCLUSIONS

Rituximab, methotrexate, procarbazine and vincristine was apparently promising in comparison with high dose-methotrexate monotherapy with manageable toxicity in this retrospective study, and further investigation is warranted.

NQPC-06 FUNCTIONAL OUTCOMES OF INITIAL TREATMENTS FOR PATIENTS WITH PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA ASSESSED BY ADL AND NEUROCOGNITIVE FUNCTION

BACKGROUNDS

Primary central nervous system lymphoma (PCNSL) frequently causes severe damage of activities of daily living (ADL) and neurocognitive function (NCF) due to extensive brain infiltration, necessitating their appropriate assessment and measures even in clinical practice. Since few studies have focused on the changes in the level of ADL and NCF in the course of PCNSL treatment, we retrospectively analyzed the effect of initial treatment of PCNSL in view of ADL and NCF.

METHODS

Among 55 patients (13 male/9 female) with newly-diagnosed PCNSL treated in our institution from January 2014 to June 2019, 22 were evaluated with both ADL and NCF. Remission induction therapies consisted of high-dose methotrexate alone (two patients), R-MPV (rituximab, methotrexate, procarbazine, and vincristine)(17 patients), and R-MPV+radiaotherapy (three patients), according to the patients’ conditions. Rehabilitation staffs intervened from the beginning, providing specific exercises and periodically evaluating scores of Karnofsky Performance Status (KPS) and Mini Mental State Examination (MMSE).

RESULTS

Mean age was 68.4 yo (range 34 to 85). After induction therapies, there were 11 complete responses (CRs), eight partial responses (PRs), and three progressive diseases (PDs). Both KPS and MMSE scores improved after induction therapy, from median 70 (40–90) to 80 (50–90), and from 24 (0–30) to 27(0–30), respectively. Among three patients who underwent RT, MMSE declined in two (one CR/one PR).

CONCLUSIONS

Case-adjusted induction therapies resulted in significant radiographical responses, and the longitudinal evaluation of ADL and NCF by rehabilitation staffs could validate their maintenance or improvement over time through effective treatments and early rehabilitation intervention. However, three was difficulty in assessing patients with higher brain dysfunction such as aphasia and social adjustment disorder. Further study is needed to include more patients and to explore more appropriate evaluation batteries and timings during and after completion of induction therapy for PCNSL.

ML-02 MULTIAGENT IMMUNOCHEMOTHERAPY, R-MPV-A, FOR PATIENTS WITH SECONDARY CENTRAL NERVOUS SYSTEM LYMPHOMA

BACKGROUNDS

Standard of care (SOC) for primary central nervous system lymphoma (PCNSL) has been induction therapy with high-dose methotrexate (MTX)-based multiagent immunochemotherapies followed by consolidation, and we have shown that one such regimen, R-MPV-A have superior efficacy over HD-MTX alone with whole brain radiotherapy (WBRT). While SOC for secondary CNS involvement of systemic diffuse large B-cell lymphoma (DLBCL)(SCNSL) has not been established. Here we report the outcome of R-MPV-A for patients with SCNSL.

PATIENTS AND METHODS

Fifteen patients with SCNSL treated with R-MPV-A from January 2014 to January 2019 in Kyorin University Hospital were eligible. Prior treatment for systemic DLBCL was mostly R-CHOP. Response and survival outcomes were evaluated.

RESULTS

Median age was 68.0 y (55–84), male/female 6/9, median KPS 70 (40–90), histopathological confirmation was achieved in 12 patients (80%; biopsy 11). RMPV (rituximab+MTX+procarbazine+vincristine) 3 cycles in 3, 4–7 cycles in 6, 8 cycles in 5. WBRT and cytarabine were delivered in 6 and 9 patients, respectively. R-MPV resulted in 6 CRs/CRus, 5 PRs, 1 SD, and 2 PDs (Response rate 73%). R-MPV-A including consolidation led to 9 CRs/CRus, 2 PRs, 1 SD, and 2 PDs (complete response rate 60%). With median F/U period of 11.2 m (0.1–51.5), 1y-PFS and 2y-PFS of R-MPV-A were 66.0% and 56.6%, 1y-OS and 2y-OS were 72.2% and 72.2%, respectively. Median PFS/OS were not reached. Consolidation cytarabine was associated with better outcome. Three deaths occurred during the treatment (20%; two during R-MPV with aged 70s, KPS 40 and 50; one presented MTX clearance delay). No other serious adverse events were observed.

CONCLUSIONS

These results suggest the certain efficacy of R-MPV-A for SCNSL. Being heavily pretreated frequently, precautions should be taken to identify high risk cases.

NQPC-03 PROGNOSTIC SIGNIFICANCE OF QUALITY-OF-LIFE EVALUATION OVER TIME IN CLINICAL PRACTICE FOR PATIENTS WITH GLIOBLASTOMA

BACKGROUNDS

Evaluation of quality of life (QOL) has been considered as an indispensable modality for assessment of treatment impact for patients with malignant brain tumor, especially glioblastoma. However, changes in patients’ QOL under clinical practice with current standard of care (SOC) have not been clearly and routinely explored, so that solid baseline QOL data under SOC are not available for reliable comparison with those with novel treatments. Here we retrospectively examined changes in QOL during SOC in glioblastoma patients.

PATIENTS AND METHODS

Patients with histologically confirmed glioblastoma treated in our institute from April 2016 to April 2019, who underwent QOL evaluations using EORTC QLQ-C-30/BN-20 were eligible. Outcomes were assessed with clinical factors including therapeutic regimens.

RESULTS

Forty-two patients, median age 64 yo (25–87), male/female 26/16, were identified having longitudinal QOL data along with medical records. Median initial KPS and mini-mental state examination (MMSE) score were 70 (20–90) and 27, respectively, suggesting this cohort containing those in good performance status. In four patients whose QOL queries were answered by a family, median MMSE was 16, indicating the impaired NCF affect self-report ability. Long term survivors without progression remained at an adequate functional scale level, while those who recurred declined in functional scale after progression, often accompanied with an increase in symptom scales associated with tumor location. The domains of declined functional scales varied among patients, and there was no clear tendency associated with patients’ backgrounds such as age and gender. The functional scale level improved in most cases when the recurrent disease was successfully treated, but it gradually declined in a stepwise fashion by repeated recurrences.

CONCLUSIONS

Changes in QOL in patients with glioblastoma were found to associate with disease status. The small number of patients who could be evaluated for QOL over time prevented extracting significant factors affecting QOL outcomes.

PATH-08. CHALLENGES IN OPTIMIZATION OF MGMT PROMOTER METHYLATION ASSAYS FOR DEVELOPMENT OF COMPANION DIAGNOSIS IN GLIOBLASTOMA

BACKGROUNDS

Despite recent limelight of precision medicine in oncology, effective targeted drugs and diagnostics for molecular markers have not been developed or approved for glioblastoma (GBM) yet. Notably, there remain multiple issues in MGMT testing, including determination of optimal assays and cutoff for methylation status, and its value as “companion diagnostics.” We compared two of MGMT assays, qualitative standard MSP and pyrosequencing, in light of compatibility, predictability, and cutoff points.

METHODS

Sixty-five newly diagnosed GBMs with two MGMT assays performed since 2006. Survival was analyzed for 48 GBMs with wildtype IDH and initial temozolomide use. Extracted DNA was subjected to bisulfite treatment, thereby MGMT status was determined.

RESULTS

Among 65 GBMs, MGMT was methylated (M) in 34, and unmethylated (U) in 31, by MSP. Median methylation rate at CpG sites by Pyro was 15.9%, with average 23.0% for M and 9.5% for U (Mann-Whitney-U, P< 0.001). MGMT status by MSP significantly correlated with that by Pyro with cutoff between 10 – 16% (Fisher, P< 0.001). Patients with MGMT M by MSP showed significantly longer PFS and OS than with U (PFS 13.5 m vs. 5.6 m, P = 0.005; OS 37.7 m vs. 15.8 m, P = 0.001). In contrast, by Pyro (cutoff 14%), only PFS was significantly better in M (11.7 m vs 5.6 m, P = 0.014), but not OS (27.9 m vs. 15.8 m, P = 0.249). No substantial gain for PFS was noted in MGMT M GBMs beyond cutoff 12% by Pyro. Multivariate analysis revealed MGMT M and KPS 70 or higher as independent factors for better PFS and OS using MSP, but only for PFS with Pyro.

CONCLUSIONS

In this study, qualitative MSP exhibited rather better discrimination of prognosis than quantitative Pyro, although showing a high concordance for MGMT status, necessitating further confirmation among assays.

PATH-45. DIFFERENT TYPES OF HYPERMUTATOR PHENOTYPE OF GLIOBLASTOMA ACCORDING TO MUTATION PATTERNS OF MISMATCH REPAIR GENES

BACKGROUND

Although precision medicine has been widely applied to routine care, only few molecular targeted drugs have been developed for glioma. Immune checkpoint inhibitors hold a potential promise to improve outcome of malignant glioma especially with the hypermutator phenotype. Mismatch repair deficiency could induce hypermutation during temozolomide (TMZ) treatment, but the mechanism of mutation acquisition is not well understood.

METHODS

We present the results of target sequencing of 57 longitudinal specimens from 27 individuals with glioblastoma (GBM). We used Ion AmpliSeq Cancer Hotspot Panel v2 (CHP) and/or Ion AmpliSeq Comprehensive Cancer Panel (CCP) for target sequencing.

RESULTS

Acquired mutations with G:C >A:T transition at non-CpG sites were found in 70% of recurrent MGMT methylated samples, whereas only 8% in MGMT unmethylated cases (p< 0.001). Two cases of hypermutator phenotype were identified in MGMT methylated, IDH wild type recurrent GBMs after TMZ chemotherapy. One case gained mutations in mismatch repair genes of MLH1, MSH2, MSH6, and PMS1. Most of the acquired mutations were G:C >A:T mutations typical to TMZ-induced hypermutation. The recurrent tumor was highly aggressive with overall survival after recurrence of 3.7 months. The other case gained mutations in mismatch repair genes of MLH1 and PMS1 only. Most of the acquired mutations were insertion mutations. The prognosis after recurrence was much longer.

CONCLUSIONS

We identified two types of hypermutator phenotype according to mutation pattern of mismatch repair genes. It has been suggested that MSH2-MSH6 complex deficient tumor cannot repair TMZ-induced mismatch mutation, thereby causing hypermutation. Conversely, MLH1-PMS1 complex deficient tumor with intact MSH2-MSH6 complex can repair mismatch mutation but is susceptible to insertion mutation. Taken together, MSH6 mutation plays a key role in TMZ-induced hypermutation, while MLH1 and PMS1 mutations might cause insertion-based hypermutation. Larger and prospective studies are warranted to clarify the mechanism, outcome, and effectiveness of checkpoint inhibitors.

First report of hepatobiliary Mycobacterium avium infection developing obstructive jaundice in a patient with neutralizing anti-interferon-gamma autoantibodies

This study describes a patient who experienced hepatobiliary Mycobacterium avium infection associated with neutralizing anti–interferon gamma (IFN-γ) autoantibodies during treatment for disseminated M. avium disease. Hepatobiliary M. avium infection should be considered in jaundiced patients with neutralizing anti–IFN-γ autoantibodies, including those receiving antimycobacterial therapy for disseminated M. avium disease.

Hepatosplenic γδ T Cell Lymphoma Involving the Brain

BACKGROUND

Brain involvement of hepatosplenic T cell lymphoma (HSTL) has not been reported so far.

CASE DESCRIPTION

We observed an extremely rare case of HSTL, which is a rare and aggressive variant of peripheral T cell lymphoma, generally showing predominant infiltration to the liver, spleen, and bone marrow and involving the brain. A 41-year-old Japanese woman presented with dysarthria and numbness of the right hand. Radiologic examination revealed a single 3-cm mass in the left frontal cortex, which was totally removed. Pathologic examination of the specimen demonstrated T cell lymphoma with a γδ cytotoxic T cell phenotype. Multiplex polymerase chain reaction analyses confirmed monoclonality of T cell receptor γ. Systemic examination revealed infiltration of atypical T lymphoid cells of the same phenotype in bone marrow and the presence of hepatosplenomegaly. We diagnosed HSTL involving the brain. The patient was treated with several courses of intensive chemotherapy, but it failed to achieve remission. She died of sepsis 4 months after the surgery.

CONCLUSIONS

HSTL can involve the brain. A diagnosis of HSTL involving the brain needs careful systemic evaluation. Timely and precise diagnosis that considers the systemic condition is important for appropriate treatment and better outcome.

Development of a novel pink-eyed dilution mouse model showing progressive darkening of the eyes and coat hair with aging

Oca2^p-cas (oculocutaneous albinism II; pink-eyed dilution castaneus) is a coat color mutant gene on mouse chromosome 7 that arose spontaneously in wild Mus musculus castaneus mice. Mice homozygous for Oca2^p-cas usually exhibit pink eyes and gray coat hair on the non-agouti genetic background, and this ordinary phenotype remains unchanged throughout life. During breeding of a mixed strain carrying this gene on the C57BL/6J background, we discovered a novel spontaneous mutation that causes darkening of the eyes and coat hair with aging. In this study, we developed a novel mouse model showing this unique phenotype. Gross observations revealed that the pink eyes and gray coat hair of the novel mutant young mice became progressively darker in color by approximately 3 months after birth. Light and transmission-electron microscopic observations revealed a marked increase in melanin pigmentation of coat hair shafts and choroid of the eye in the novel mice compared to that in the ordinary mice. Sequence analysis of Oca2^p-cas revealed a 4.1-kb deletion involving exons 15 and 16 of its wild-type gene. However, there was no sequence difference between the two types of mutant mice. Mating experiments suggested that the novel mutant phenotype was not inherited in a simple fashion, due to incomplete penetrance. The novel spontaneous mutant mouse is the first example of progressive hair darkening animals and is an essential animal model for understanding of the regulation mechanisms of melanin biosynthesis with aging.

Recovery of nanomolecular electronic states from tunneling spectroscopy: LDOS of low-dimensional phthalocyanine molecular structures on Cu(111)

Organic nanomolecules have become one of the most attractive materials for new nanoelectronics devices. Understanding of the electronic density of states around the Fermi energy of low-dimensional molecules is crucial in designing the electronic properties of molecular devices. The low dimensionality of nanomolecules results in new electronic properties owing to their unique symmetry. Scanning tunneling spectroscopy is one of the most effective techniques for studying the electronic states of nanomolecules, particularly near the Fermi energy (±1.5 eV), whereas these molecular electronic states are frequently buried by the tunneling probability background in tunneling spectroscopy, resulting in incorrect determination of the molecular electronic states. Here, we demonstrate how to recover nanomolecular electronic states from dI/dV curves obtained by tunneling spectroscopy. Precise local density of states (LDOS) peaks for low-dimensional nanostructures (monolayer ultrathin films, one-dimensional chains, and single molecules) of phthalocyanine (H2Pc) molecules grown on noble fcc-Cu(111) were obtained.

Hepatotoxicity of sub-nanosized platinum particles in mice

Nano-sized materials are widely used in consumer products, medical devices and engineered pharmaceuticals. Advances in nanotechnology have resulted in materials smaller than the nanoscale, but the biologic safety of the sub-nanosized materials has not been fully assessed. In this study, we evaluated the toxic effects of sub-nanosized platinum particles (snPt) in the mouse liver. After intravenous administration of snPt (15 mg/kg body weight) into mice, histological analysis revealed acute hepatic injury, and biochemical analysis showed increased levels of serum markers of liver injury and inflammatory cytokines. In contrast, administration of nano-sized platinum particles did not produce these abnormalities. Furthermore, snPt induced cytotoxicity when directly applied to primary hepatocytes. These data suggest that snPt have the potential to induce hepatotoxicity. These findings provide useful information on the further development of sub-nanosized materials.

Increased plasma levels of high mobility group box 1 in patients with acute liver failure

BACKGROUND

High-mobility group box 1 (HMGB1) is a monocyte-derived late-acting inflammatory mediator, which is released in conditions such as shock, tissue injury and endotoxin-induced lethality. In this study, we determined the plasma and hepatic tissue levels of HMGB1 in patients with acute liver failure (ALF).

PATIENTS AND METHODS

We determined the plasma levels of HMGB1 and aspartate aminotransferase (AST) in 7 healthy volunteers (HVs), 40 patients with liver cirrhosis (LC), 37 patients with chronic hepatitis (CH), 18 patients with severe acute hepatitis (AH), and 14 patients with fulminant hepatitis (FH). The 14 patients with FH were divided into two subgroups depending upon the history of plasma exchange (PE) before their plasma sample collection. The hepatic levels of HMGB1 were measured in tissue samples from 3 patients with FH who underwent living-donor liver transplantation and from 3 healthy living donors. Hepatic tissue samples were also subjected to immunohistochemical examination for HMGB1.

RESULTS

The plasma levels of HMGB1 (ng/ml) were higher in patients with liver diseases, especially in FH patients with no history of PE, than in HVs (0.3 ± 0.3 in HVs, 4.0 ± 2.0 in LC, 5.2 ± 2.6 in CH, 8.6 ± 4.8 in severe AH, 7.8 ± 2.7 in FH with a history of PE, and 12.5 ± 2.6 in FH with no history of PE, p < 0.05 in each comparison). There was a strong and statistically significant relationship between the mean plasma HMGB1 level and the logarithm of the mean AST level (R = 0.900, p < 0.05). The hepatic tissue levels of HMGB1 (ng/mg tissue protein) were lower in patients with FH than in healthy donors (539 ± 116 in FH vs. 874 ± 81 in healthy donors, p < 0.05). Immunohistochemical staining for HMGB1 was strong and clear in the nuclei of hepatocytes in liver sections from healthy donors, but little staining in either nuclei or cytoplasm was evident in specimens from patients with FH.

CONCLUSION

We confirmed that plasma HMGB1 levels were increased in patients with ALF. Based on a comparison between HMGB1 contents in normal and ALF livers, it is very likely that HMGB1 is released from injured liver tissue.

Sister chromatid exchanges in ring chromosomes following X‐irradiation of human lymphocytes

PURPOSE

To examine whether X-rays induce sister chromatid exchanges (SCE).

MATERIALS AND METHODS

Peripheral lymphocytes irradiated in vitro or in vivo were cultured and treated with okadaic acid to generate premature chromosome condensation (PCC). When identical spreads were analysed using conventional Giemsa staining and pan-centromeric fluorescence in situ hybridization painting, ring chromosomes were observed.

RESULTS

In PCC preparations, cells in the late G(2) phase and late M phase were observed. In late M phase cells, 17-20% of ring chromosomes lacked one chromatid (single-chromatid ring), irrespective of dose. Both the distribution patterns of centromeres in rings and intercentromere distances in dicentric rings indicate that a considerable number of single-chromatid rings might be formed by SCE occurring in a chromosome-type ring, thereby joining strands of two rings, followed by a transformation into one ring. These single-chromatid rings were less stable in vivo than chromosome-type rings.

CONCLUSION

Single-chromatid rings visualized clearly using PCC techniques indicate SCE in the respective rings. Contrary to the conventional SCE-detecting technique, this approach does not require the use of bromodeoxyuridine, which itself leads to SCE. Some of the observed SCE might be secondary products resulting from the repair of radiation-induced DNA damage, while others may be spontaneous.

A Japanese herbal medicine, Sho-saiko-to, prevents gut ischemia/reperfusion-induced hepatic microvascular dysfunction in rats

BACKGROUND AND AIM

We have reported that gut ischemia/reperfusion (I/R) causes hepatic microvascular dysfunction. Nitric oxide (NO) has been found to be a modulator of the adhesive interactions between leukocytes, platelets, and endothelial cells. Sho-saiko-to (TJ-9), a Japanese herbal medicine, is reported to have protective effects against liver injury and to regulate NO production. The objective of this study was to determine whether TJ-9 affects hepatic microvascular dysfunction elicited by gut I/R, and to investigate the role of NO.

METHODS

Male Wistar rats were exposed to 30 min of gut ischemia followed by 60 min of reperfusion. Intravital microscopy was used to monitor leukocyte recruitment and the number of non-perfused sinusoids (NPS). Plasma tumor necrosis factor (TNF)-alpha and alanine aminotransferase (ALT) activities were measured. In another set of experiments, TJ-9 (1 g/kg per day intragastrically) was administered to rats for 7 days. In some experiments, dexamethasone (ST) (2 mg/kg per day intravenously) was administered.

RESULTS

In control rats, gut I/R elicited increases in the number of stationary leukocytes, NPS, and plasma TNF-alpha and ALT activities, and these changes were mitigated by the pretreatment with TJ-9. Pretreatment with an NO synthase inhibitor diminished the protective effects of TJ-9 on the increase in leukostasis in the pericentral region, NPS, and plasma TNF-alpha levels, but not its effect on the increase in leukostasis in the midzonal region, total number of stationary leukocytes, or plasma ALT activities. Pretreatment with TJ-9 increased plasma nitrite/nitrate levels. The responses caused by gut I/R were attenuated by the pretreatment with ST. Pretreatment with an NO synthase inhibitor did not affect the effect of ST.

CONCLUSIONS

These results suggest that TJ-9 attenuates the gut I/R-induced hepatic microvascular dysfunction and inflammatory responses such as TNF-alpha production in the early phase via enhancement of NO production, and sequential hepatocellular damage via its anti-inflammatory effect like corticosteroid effect.