Chromosome arm length, and a species-specific determinant, define chromosome arm width.

Mitotic chromosomes in different organisms adopt various dimensions. What defines these dimensions is scarcely understood. Here, we compare mitotic chromosomes in budding and fission yeasts harboring similarly sized genomes distributed among 16 or 3 chromosomes, respectively. Hi-C analyses and superresolution microscopy reveal that budding yeast chromosomes are characterized by shorter-ranging mitotic chromatin contacts and are thinner compared with the thicker fission yeast chromosomes that contain longer-ranging mitotic contacts. These distinctions persist even after budding yeast chromosomes are fused to form three fission-yeast-length entities, revealing a species-specific organizing principle. Species-specific widths correlate with the known binding site intervals of the chromosomal condensin complex. Unexpectedly, within each species, we find that longer chromosome arms are always thicker and harbor longer-ranging contacts, a trend that we also observe with human chromosomes. Arm length as a chromosome width determinant informs mitotic chromosome formation models.

Unraveling pathologies underlying chromosomal instability in cancers.

Aneuploidy is a widespread feature of malignant tumors that arises through persistent chromosome mis-segregation in mitosis associated with a pathological condition called chromosomal instability, or CIN. Since CIN is known to have a causal relationship with poor prognosis accompanying by multi-drug resistance, tumor relapse, and metastasis, many research groups have endeavored to understand the mechanisms underlying CIN. In this review, we overview possible etiologies of CIN. The key processes to achieve faithful chromosome segregation include the regulation of sister chromatid cohesion, kinetochore-microtubule attachment, bipolar spindle formation, spindle-assembly checkpoint, and the activity of separase. Aberrant chromosome structures during DNA replication might also be a potential cause of CIN. Defective regulation in these processes can lead to chromosome mis-segregation, manifested by lagging chromosomes, and DNA bridges in anaphase, leading to gross chromosome rearrangements. Investigation into the molecular etiologies of CIN should allow us to explore novel strategies to intervene in CIN to control cancers.

Factors for the optimal selection of granulocyte colony-stimulating factor preparations and predictors for R-CHOP dose reductions/delays among patients with non-Hodgkin B-cell lymphoma (STOP FN in NHL 2 subanalysis).

BACKGROUND: A classification tree was used to analyze background factors for granulocyte colony-stimulating factor (G-CSF) preparation selection for febrile neutropenia (FN) prophylaxis in Japanese patients with non-Hodgkin B-cell lymphoma receiving the first R-CHOP cycle. METHODS: This was a subanalysis of the retrospective observational study STOP FN in NHL 2 (UMIN000029534). Patient characteristics, changes in neutrophil count, incidence and severity of neutropenia, and risk factors for dose reduction/delay of R-CHOP were assessed by G-CSF formulation. RESULTS: Among 234 patients in cycle 1, 25.6% received no G-CSF preparation, 52.1% received daily G-CSF, and 22.2% received pegfilgrastim. Pegfilgrastim use was most frequent among patients aged ≥ 80 years, while that of daily G-CSF was most frequent in patients with lymphocyte count (LC) < 1000 cells/µL. Changes in neutrophil count were more marked with pegfilgrastim compared with daily G-CSF and no G-CSF. Relevant factors for G-CSF preparation selection in the first R-CHOP cycle were age ≥ 80 years and LC < 1000 cells/µL; for chemotherapy dose reduction were FN onset in cycle 1 and female sex; and for dose delay was hemoglobin (< 12 g/dL). After cycle 2 and onward, pegfilgrastim use increased markedly (72.6%) compared with cycle 1 (22.2%), with significantly greater proportions continuing pegfilgrastim use and switching from daily G-CSF. CONCLUSION: Relevant factors for G-CSF preparation selection were age ≥ 80 years and LC < 1000 cells/µL. The use of pegfilgrastim increased markedly after cycle 2. These results may be useful for selecting appropriate G-CSF preparations in the first R-CHOP cycle. TRIAL REGISTRATION: UMIN000029534; registered on 13 October 2017, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000033733 .

MYD88 L265P mutation detected by digital PCR as a prognostic factor in patients with diffuse large B-cell lymphoma in rituximab era.

The central nervous system (CNS) relapse in patients with diffuse large B cell lymphoma (DLBCL) is fatal as there are no effective rescue treatments. To test if the presence of the MYD88 L265P mutation is a prognostic factor for secondary CNS relapse, we carried out the digital PCR analysis of 134 samples from patients with DLBCL at diagnosis. The MYD88 L265P mutations were detected in 22 (16.4%) patients, particularly in those with a non-GC subtype, CD5-positive, high absolute monocyte count, extra-nodal lymphoma, and B symptoms. Nine patients showed low signal in digital PCR but were deemed positive for the MYD88 L265P mutation by the nested allele-specific PCR. The remaining 103 patients were negative according to the results of both the PCR analyses. With a median follow-up period of 64 months, the carriers of MYD88 L265P mutation exhibited inferior CNS relapse-free survival at 5 years (53.2% versus 96% and 100%, respectively, P < 0.001) with a significant effect of the mutation demonstrated by the multivariate analysis (hazard ratio 5.1; 95% CI 1.2-22.9, P = 0.02). This suggests that the MYD88 L265P mutation plays a critical role in the progression of DLBCL to CNS.

Insignificance of surveillance imaging in patients with diffuse large B-cell lymphoma who achieved first complete remission: a retrospective cohort study.

The aim of this study was to evaluate the value of scheduled imaging for patients who achieved first complete remission after CHOP-like chemotherapy plus rituximab. In this retrospective cohort study, we included 759 patients newly diagnosed with de novo diffuse large B-cell lymphoma (DLBCL) at the Cancer Institute, Japanese Foundation for Cancer Research. Relapsed patients were divided into two groups based on method of diagnosis: clinical symptoms (symptom group, n = 57) or scheduled imaging (imaging group, n = 27). Our primary goal was to compare overall survival and relapse-free survival between the two groups. No significant difference in outcomes was found between the symptom and imaging groups. Median overall survival [7.5 years; 95% confidence interval (CI) 4.0-9.7 vs. 9.1 years; 95% CI 2.7 to not reached; P = 0.747), and median relapse-free survival (1.8 years; 95% CI 1.4-2.5 vs. 2.4 years; 95% CI 1.2-4.4; P = 0.108). Surveillance imaging in patients with DLBCL who achieved first complete remission did not demonstrate an advantage in terms of overall survival or relapse-free survival.

Incidence and risk factors for febrile neutropenia in Japanese patients with non-Hodgkin B cell lymphoma receiving R-CHOP: 2-year experience in a single center (STOP FN in NHL 2).

BACKGROUND: Myelosuppressive chemotherapy-induced febrile neutropenia (FN) is a life-threatening condition. Patients receiving granulocyte colony-stimulating factors (G-CSF) have shorter duration of neutropenia, faster recovery from fever, and shorter duration of antibiotics use. Most strategies for FN prevention using daily G-CSF and pegfilgrastim are based on overseas studies. Data on Japanese patients were lacking; thus, we previously determined the incidence of FN in non-Hodgkin B cell lymphoma (B-NHL) patients at our center. Here, we aimed to gain additional insights into pegfilgrastim use in this population. METHODS: This single-center, retrospective, observational study (STOP FN in NHL 2) enrolled patients with B-NHL who underwent a regimen comprising rituximab and CHOP therapy over a 2-year period (January 2015-June 2017). The incidence of FN in cycle 1 of chemotherapy, risk factors for FN development, and use of daily G-CSF and pegfilgrastim were evaluated. RESULTS: We evaluated 239 patients: 61 patients did not receive G-CSF and 178 received G-CSF. The incidence of FN was 10.5% (95% confidence interval [CI] 6.9-15.1%) in cycle 1 and 13.0% (95% CI 9.0-17.9%) in all cycles. The FN incidence was significantly lower (P = 0.0008) in patients receiving daily G-CSF and pegfilgrastim than patients not receiving G-CSF. Significant risk factors for FN were age ≥ 65 years, albumin < 3.5 g/dL, hemoglobin < 12 g/dL, and no prophylaxis with daily G-CSF/pegfilgrastim during cycle 1. CONCLUSIONS: The incidence of FN in cycle 1 and in all cycles and the identified risk factors were similar with those we previously reported; thus, our results validate previous findings. TRIAL REGISTRATION: UMIN000029534.

Delayed recovery of serum immunoglobulin G is a poor prognostic marker in patients with follicular lymphoma treated with rituximab maintenance.

Clinical trials involving various treatment schedules for rituximab maintenance have been conducted for patients with follicular lymphoma (FL) and have not confirmed their impact on serum immunoglobulin (sIg) levels until the completion of maintenance. However, the long-term use of rituximab is a concern because of circulating plasma cell-depletion risk, suggesting that the mechanism of change in sIg levels after RM has not been determined. Additionally, the relationship between host humoral immunity and the prognosis of patients with B cell malignancies has not been determined. We retrospectively investigated data from 213 patients with FL from a single institute who achieved at least a partial response with rituximab, cyclophosphamide, vincristine, and prednisolone with or without doxorubicin. Of these, 166 patients underwent RM with a median period of 1.6 years. A significantly delayed recovery of sIgG levels was observed in the maintenance group until 3 years after RM in comparison to the observation group. A multivariate analysis showed that a sIgG level of < 718 mg/dl 1 year after RM was an independent predictor for poor progression-free survival (PFS) (hazard ratio, 2.3; P = 0.04). Therefore, the sIgG levels scarcely recovered and were significantly delayed after RM, leading to shorter PFS in patients with FL.

Efficacy of chemotherapy in extremely elderly patients with diffuse large B-cell lymphoma.

The safety and effective dose of chemotherapy in treating non-Hodgkin lymphoma in elderly patients is yet to be established. In this study, we assessed the prognosis of diffuse large B-cell lymphoma (DLBCL) in elderly patients (≥75 years) treated with an optimal dose of R-CHOP. No significant differences were observed in progression-free survival between elderly patients and patients aged <74 years with DLBCL. Furthermore, no differences were observed between full-dose R-CHOP and 80% dose R-CHOP groups. Median relative dose intensity was 0.80 in elderly patients with DLBCL. Thus, our data suggested that 80% dose R-CHOP is tolerable and effective in these patients.

Incidence and risk factors of febrile neutropenia in patients with non-Hodgkin B-cell lymphoma receiving R-CHOP in a single center in Japan.

PURPOSE: The incidence of and risk factors for febrile neutropenia (FN) in Japanese non-Hodgkin B-cell lymphoma (B-NHL) patients receiving rituximab, cyclophosphamide, doxorubicin, vincristine, and predonisolone (R-CHOP) chemotherapy are unknown. We conducted this study to address this issue. METHODS: In this single-center, retrospective, observational study, 466 patients with B-NHL who completed an R-CHOP regimen within a 7-year period and who planned to undergo at least three cycles of this regimen were analyzed. The following FN-related factors were assessed: fever, infection, disease state, neutrophil count, and prophylactic interventions such as use of antibiotics and/or granulocyte colony-stimulating factor (G-CSF). We simulated the FN incidence and 95% confidence interval (CI) of patients without prophylaxis with G-CSF (cycle 1) using bootstrap sampling. RESULTS: The incidence of FN was 9.1% (42 of 462) in cycle 1 and 12.3% (57 of 462 patients) throughout all cycles, with 73.7% (42/57) developing FN during cycle 1. Risk factors for FN among patients with B-NHL treated with R-CHOP were albumin <35 g/L (p = 0.0047), relative dose intensity <85% (p = 0.0007), and lack of prophylaxis with G-CSF (p = 0.0006) in cycle 1. In the simulation analysis, the estimated FN incidence in cycle 1 was 16.2% (95% CI [10.9-22.2]). CONCLUSIONS: At 9.1% in cycle 1 and 12.3% throughout all cycles, the incidence of FN was lower than previously reported, possibly reflecting the appropriate use of G-CSF in this clinical setting. For patients with risk factors, the prophylaxis with G-CSF may decrease the occurrence of FN.

Absolute peripheral monocyte count at diagnosis predicts central nervous system relapse in diffuse large B-cell lymphoma.

Recently, elevated peripheral blood monocyte counts at diagnosis have been shown to be an independent marker associated with poor prognosis in patients with both non-Hodgkin and Hodgkin lymphoma. In this study, we retrospectively analyzed the data from a total of 550 patients with diffuse large B-cell lymphoma and evaluated the relationship between central nervous system relapse and absolute monocyte counts at diagnosis. Twenty-six patients developed central nervous system relapse. The central nervous system relapse-free survival rate was significantly lower in patients with the absolute monocyte counts ≥ 0.51 × 10(9)/L (87.8% versus 96.4%; P<0.001). This association was independently significant after adjusting for other significant factors, including systemic relapse as a time-dependent covariate by multivariate analysis (hazard ratio 2.46; 95% confidence intervals 1.05-5.75; P=0.039). These results suggest that the absolute monocyte count at diagnosis is an independent significant risk factor for central nervous system relapse in patients with diffuse large B-cell lymphoma.