Results of a multi-institutional, randomized, non-inferiority, phase III trial of accelerated fractionation versus standard fractionation in radiation therapy for T1-2N0M0 glottic cancer: Japan Clinical Oncology Group Study (JCOG0701)

Background

We assessed the non-inferiority of accelerated fractionation (AF) (2.4 Gy/fraction) compared with standard fractionation (SF) (2 Gy/fraction) regarding progression-free survival (PFS) in patients with T1-2N0M0 glottic cancer (GC).

Patients and methods

In this multi-institutional, randomized, phase III trial, patients were enrolled from 32 Japanese institutions. Key inclusion criteria were GC T1-2N0M0, age 20-80, Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function. Patients were randomly assigned to receive either SF of 66-70 Gy (33-35 fractions), or AF of 60-64.8 Gy (25-27 fractions). The primary end point was the proportion of 3-year PFS. The planned sample size was 360 with a non-inferiority margin of 5%.

Results

Between 2007 and 2013, 370 patients were randomized (184/186 to SF/AF). Three-year PFS was 79.9% (95% confidence interval [CI] 73.4-85.4) for SF and 81.7% (95% CI 75.4-87.0) for AF (difference 1.8%, 91% CI-5.1% to 8.8%; one-sided P = 0.047 > 0.045). The cumulative incidences of local failure at 3 years for SF/AF were 15.9%/10.3%. No significant difference was observed in 3-year overall survival (OS) between SF and AF. Grade 3 or 4 acute and late toxicities developed in 22 (12.4%)/21 (11.5%) and 2 (1.1%)/1 (0.5%) in the SF/AF arms.

Conclusion

Although the non-inferiority of AF was not confirmed statistically, the similar efficacy and toxicity of AF compared with SF, as well as the practical convenience of its fewer treatment sessions, suggest the potential of AF as a treatment option for early GC.

Clinical trials registration

UMIN Clinical Trial Registry, number UMIN000000819.

Plk1 phosphorylation of CAP-H2 triggers chromosome condensation by condensin II at the early phase of mitosis

Condensin complexes play crucial roles in chromosome condensation that is a fundamental process to establish the "rod-like" shape of chromosome structure in mitosis. Failure of the chromosome assembly causes chromosome segregation errors and subsequent genomic instability. However, a molecular mechanism that controls condensin function for the chromosomal organization has not been fully understood. Here, we show that the abundance of CAP-H2, one of the condensin II subunits, is fluctuated during the cell cycle in accordance with Plk1 kinase activity. Inhibition of Plk1 leads to Cdc20-mediated degradation of CAP-H2 in mitosis. Plk1 phosphorylation of CAP-H2 at Ser288 is required for the accumulation of CAP-H2 and accurate chromosomal condensation during prophase. These findings suggest that Plk1 phosphorylation regulates condensin II function by modulating CAP-H2 expression levels to facilitate proper mitotic chromosome organization.

The functional role for condensin in the regulation of chromosomal organization during the cell cycle

In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.

Susceptibility quantitative trait loci for pathogenic leucocytosis in SCG/Kj mice, a spontaneously occurring crescentic glomerulonephritis and vasculitis model

The spontaneous crescentic glomerulonephritis-forming/Kinjoh (SCG/Kj) mouse, a model of human crescentic glomerulonephritis (CrGN) and systemic vasculitis, is characterized by the production of myeloperoxidase-specific anti-neutrophil cytoplasmic autoantibody (MPO-ANCA) and marked leucocytosis. This study was performed to identify the specific populations of leucocytes associated with CrGN and susceptibility loci for pathogenic leucocytosis. Four hundred and twenty female (C57BL/6 × SCG/Kj) F2 intercross mice were subjected to serial flow cytometry examination of the peripheral blood (PB). Kidney granulocytes and monocytes were examined histopathologically. Linkage analyses were performed with 109 polymorphic microsatellite markers. Correlation studies revealed that increase of the granulocytes, F4/80(+) cells, CD3(+) CD4(-) CD8(-) T cells and dendritic cells (DCs) in peripheral blood (PB) were associated significantly with glomerulonephritis, crescent formation and vasculitis. In kidney sections, F4/80(low) cells were observed in crescent, while F4/80(high) cells were around the Bowman's capsules and in the interstitium. Numbers of F4/80(+) cells in crescents correlated significantly with F4/80(+) cell numbers in PB, but not with numbers of F4/80(+) cells in the interstitium. Genome-wide quantitative trait locus (QTL) mapping revealed three SCG/Kj-derived non-Fas QTLs for leucocytosis, two on chromosome 1 and one on chromosome 17. QTLs on chromosome 1 affected DCs, granulocytes and F4/80(+) cells, but QTL on chromosome 17 affected DCs and granulocytes. We found CrGN-associated leucocytes and susceptibility QTLs with their positional candidate genes. F4/80(+) cells in crescents are considered as recruited inflammatory macrophages. The results provide information for leucocytes to be targeted and genetic elements in CrGN and vasculitis.

Mps1 phosphorylation of condensin II controls chromosome condensation at the onset of mitosis

Mps1 is necessary for proper condensin II loading onto chromatin and subsequent chromosome condensation during mitosis.

During mitosis, genomic DNA is condensed into chromosomes to promote its equal segregation into daughter cells. Chromosome condensation occurs during cell cycle progression from G2 phase to mitosis. Failure of chromosome compaction at prophase leads to subsequent misregulation of chromosomes. However, the molecular mechanism that controls the early phase of mitotic chromosome condensation is largely unknown. Here, we show that Mps1 regulates initial chromosome condensation during mitosis. We identify condensin II as a novel Mps1-associated protein. Mps1 phosphorylates one of the condensin II subunits, CAP-H2, at Ser492 during mitosis, and this phosphorylation event is required for the proper loading of condensin II on chromatin. Depletion of Mps1 inhibits chromosomal targeting of condensin II and accurate chromosome condensation during prophase. These findings demonstrate that Mps1 governs chromosomal organization during the early stage of mitosis to facilitate proper chromosome segregation.

Locoregional recurrence risk factor and indications for postmastectomy radiotherapy in Japanese patients with tumors 5 cm or larger

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Background: Locoregional recurrence (LRR) after mastectomy reduces the patient’s quality of life and survival. There is a consensus that postmastectomy radiotherapy (PMRT) helps achieve locoregional control and reduces LRR. However, in patients with large tumors, the question of which variables affect the likelihood of LRR and the role of PMRT has been the subject of substantial controversy. This study investigated what are risk factors for LRR and the efficacy of PMRT in this Japanese patient population.

Methods: This study examined 589 cases of invasive breast carcinoma with tumors 5 cm or larger from 1998 to 2008. We divided the study population into 3 groups: patients with negative nodes, 1-3 positive nodes, and ≥4 positive nodes. The relationship between various clinicopathological variables and LRR was examined and the relationship between LRR and PMRT was estimated.

Results: During the median follow-up was 44.2 months, 38 (6.5%) patients experienced LRR. In the multivariate analysis, independent predictors of LRR include pectoral invasion in patients with 1-3 positive nodes, and severity lymphatic invasion, estrogen receptor-negative status, and nodal ratio of positive/excised nodes ≥ 0.50 in patients with ≥4 positive nodes. In patients without positive nodes, none of the examined variables were significantly associated with LRR. PMRT did not improve the outcome of the patients at highest risk who had these variables.

Conclusions: The efficacy of PMRT in patients with large tumors was not shown. In the context of systemic therapy and adequate lymph node dissection, PMRT by itself had a limited role in providing locoregional control. Due to the very low incidence of LRR observed, PMRT was not necessary for patients with large tumors without lymph node metastasis. The indication for PMRT in patients with metastatic nodes remains controversial.

CD5-positive diffuse large B-cell lymphoma: a retrospective study in 337 patients treated by chemotherapy with or without rituximab

BACKGROUND

CD5-positive (CD5+) diffuse large B-cell lymphoma (DLBCL) shows poor prognosis and frequent central nervous system (CNS) relapses under anthracycline-containing chemotherapy. The aim of this study was to determine the prognosis and CNS relapse incidence of CD5+ DLBCL in the rituximab era.

PATIENTS AND METHODS

We analyzed 337 patients with CD5+ DLBCL who received chemotherapy with (R-chemotherapy group; n = 184) or without (chemotherapy group; n = 153) rituximab.

RESULTS

No significant difference was found in clinical background comparisons between the two groups. In the R-chemotherapy group, 60% of the patients were older than 65 years at diagnosis. Both the complete response rate and overall survival (OS) were significantly better in the R-chemotherapy group (P = 0.0003 and P = 0.002, respectively). Multivariate analysis confirmed that chemotherapy without rituximab was associated with unfavorable OS. However, the probability of CNS relapse did not differ between the two groups (P = 0.89). The CNS relapse was strongly associated with short OS (P < 0.0001). In the R-chemotherapy group, 83% of patients who experienced CNS relapse had parenchymal disease.

CONCLUSIONS

Our results indicate that rituximab improves the OS of patients with CD5+ DLBCL but does not decrease the CNS relapse rate. More effective treatments with CNS prophylaxis are needed for CD5+ DLBCL patients.