Subtyping of triple-negative breast cancers: its prognostication and implications in diagnosis of breast origin.

BACKGROUND: Triple-negative breast cancer (TNBC) subtyping by gene profiling has provided valuable clinical information. Here, we aimed to evaluate the relevance of TNBC subtyping using immunohistochemistry (IHC), which could be a more clinically practical approach, for prognostication and applications in patient management. METHODS: A total of 123 TNBC cases were classified using androgen receptor (AR), CD8, Forkhead box C1 protein (FOXC1), and doublecortin-like kinase 1 (DCLK1) into luminal androgen receptor (LAR), basal-like immunosuppressive (BLIS), mesenchymal-like (MES), and immunomodulatory (IM) subtypes. The IM cases were further divided into the IM-excluded and IM-inflamed categories by CD8 spatial distribution. Their clinicopathological and biomarker profiles and prognoses were evaluated. RESULTS: LAR (28.6%) and MES (11.2%) were the most and least frequent subtypes. The IHC-TNBC subtypes demonstrated distinct clinicopathological features and biomarker profiles, corresponding to the reported features in gene profiling studies. IM-inflamed subtype had the best outcome, while BLIS had a significantly poorer survival. Differential breast-specific marker expressions were found. Trichorhinophalangeal syndrome type 1 (TRPS1) was more sensitive for IM-inflamed and BLIS, GATA-binding protein 3 (GATA3) for IM-excluded and MES, and gross cystic disease fluid protein 15 (GCDFP15) for LAR subtypes. CONCLUSIONS: Our findings demonstrated the feasibility of IHC surrogates to stratify TNBC subtypes with distinct features and prognoses. The IM subtype can be refined by its CD8 spatial pattern. Breast-specific marker expression varied among the subtypes. Marker selection should be tailored accordingly.

Challenges in oncology career: are we closing the gender gap? Results of the new ESMO Women for Oncology Committee survey.

BACKGROUND: Following a European Society for Medical Oncology Women for Oncology (ESMO W4O) survey in 2016 showing severe under-representation of female oncologists in leadership roles, ESMO launched a series of initiatives to address obstacles to gender equity. A follow-up survey in October 2021 investigated progress achieved. MATERIALS AND METHODS: The W4O questionnaire 2021 expanded on the 2016 survey, with additional questions on the impact of ethnicity, sexual orientation and religion on career development. Results were analysed according to respondent gender and age. RESULTS: The survey sample was larger than in 2016 (n = 1473 versus 482), especially among men. Significantly fewer respondents had managerial or leadership roles than in 2016 (31.8% versus 51.7%). Lack of leadership development for women and unconscious bias were considered more important in 2021 than in 2016. In 2021, more people reported harassment in the workplace than in 2016 (50.3% versus 41.0%). In 2021, ethnicity, sexual orientation and religion were considered to have little or no impact on professional career opportunities, salary setting or related potential pay gap. However, gender had a significant or major impact on career development (25.5% of respondents), especially in respondents ≤40 years of age and women. As in 2016, highest ranked initiatives to foster workplace equity were promotion of work-life balance, development and leadership training and flexible working. Significantly more 2021 respondents (mainly women) supported the need for culture and gender equity education at work than in 2016. CONCLUSIONS: Gender remains a major barrier to career progression in oncology and, although some obstacles may have been reduced since 2016, we are a long way from closing the gender gap. Increased reporting of discrimination and inappropriate behaviour in the workplace is a major, priority concern. The W4O 2021 survey findings provide new evidence and highlight the areas for future ESMO interventions to support equity and diversity in oncology career development.

Female leadership in oncology-has progress stalled? Data from the ESMO W4O authorship and monitoring studies.

BACKGROUND: Exploratory research showed that female oncologists are frequently under-represented in leadership roles. European Society for Medical Oncology (ESMO) Women for Oncology (W4O) therefore implemented gender equality programs in career development and established international studies on female representation at all stages of the oncology career pathway. METHODS: For 2017-2019, data were collected on (i) first and last authorship of publications in five major oncology journals and (ii) representation of women in leadership positions in oncology-as invited speakers at National/International congresses, board members or presidents of National/International societies and ESMO members. The 2015/2016 data from the first published W4O Study were incorporated for comparisons. RESULTS: Across 2017-2019, female oncologists were significantly more likely to be first than last authors (P < 0.001). The proportion of female first authors was similar across years: 38.0% in 2017, 37.1% in 2018, 41.0% in 2019 (P = 0.063). The proportion of female last authors decreased from 30.4% in 2017 to 24.2% in 2018 (P = 0.0018) and increased to 28.5% in 2019 (P = 0.018). Across 2015-2019, invited speakers at International/National oncology congresses were significantly less likely to be female than male (P < 0.001; 29.7% in 2015 to 36.8% in 2019). Across 2016-2019, board members of International/National oncology societies were significantly less likely to be female than male (P < 0.001; 26.8% in 2016 to 35.8% in 2019). There were statistically significant increasing trends in female speakers and board members across the study periods (P < 0.001 for both). Societies with a female president had a higher proportion of female board members across these periods (P = 0.026). CONCLUSIONS: Reported progress towards gender equality in career development in oncology is real but slow. Women in leadership positions are essential for encouraging young women to aspire to and work towards similar or greater success. Therefore, continued monitoring is needed to inform ESMO W4O initiatives to promote gender balance at all stages of the career pathway.

Has COVID-19 had a greater impact on female than male oncologists? Results of the ESMO Women for Oncology (W4O) Survey.

BACKGROUND: European Society for Medical Oncology Women for Oncology (ESMO W4O) research has previously shown under-representation of female oncologists in leadership roles. As early reports suggested disproportionate effects of the COVID-19 pandemic on women, the ESMO W4O Committee initiated a study on the impact of the pandemic on the lives of female and male oncologists. METHODS: A questionnaire was sent to ESMO members and put on the ESMO website between 8 June 2020 and 2 July 2020. Questions focused on the working (hospital tasks, laboratory tasks, science) and home (household management, childcare, parent care, personal care) lives of oncologists during and after COVID-19-related lockdowns. RESULTS: Of 649 respondents, 541 completed the questionnaire. Of these, 58% reported that COVID-19 had affected their professional career, 83% of whom said this was in a negative way (85% of women versus 76% of men). Approximately 86% reported that COVID-19 had changed their personal life and 82% their family life. Women were again significantly more affected than men: personal life (89% versus 78%; P = 0.001); family life (84% versus 77%; P = 0.037). During lockdowns, women reported increased time spent on hospital and laboratory tasks compared with men (53% versus 46% and 33% versus 26%, respectively) and a significantly higher proportion of women than men spent less time on science (39% versus 25%) and personal care (58% versus 39%). After confinement, this trend remained for science (42% versus 23%) and personal care (55% versus 36%). CONCLUSIONS: The COVID-19 pandemic has adversely affected the professional and home lives of oncologists, especially women. Reduced research time for female oncologists may have long-lasting career consequences, especially for those at key stages in their career. The gender gap for promotion to leadership positions may widen further as a result of the pandemic.

[Application of three-staged paramedian forehead flap in reconstruction and repair of full-thickness nasal defect].

Objective: To evaluate the application of three-staged paramendian forehead flap technique in reconstruction of severe full-thickness nasal defect. Methods: Clinical data of 7 cases with nasal reconstruction by three-staged forehead flap technique in the First Affiliated Hospital of Xinjiang Medical University and HongKong University Shenzhen Hospital between June 2016 and October 2019 was retrospectively reviewed. All were males aged from 10 to 71 years. There were 4 cases of basal cell carcinoma of the external nose, 2 cases of traumatic nasal defects and 1 case of large rhinophyma. All the operations were performed with the paramedian forehead flap in three stages. In stage Ⅰ, full layered forehead flap was transposed to the nasal detect. Lining flaps were reconstructed with folded forehead skin (n=4), turn-over flap plus septal chondro mucosal pivotal flap (n=2), or bipedicled vestibular skin and nasal mucosa advancement flap (n=1). According to the reconstruction mode of the lining flaps, whether to implant cartilage to reconstruct the external nasal stent at stage Ⅰ was determined. At stage Ⅱ, the folded flaps were partly or completely separated from the covering flaps along the free edges of nasal alar. All the excess soft tissue including subcutaneous fat and frontalis muscle were excised, cartilage grafts were placed or sculpted to make an ideal nasal contour. The covering flaps were then returned on the recontoured, three-dimensional recipient bed. At stage Ⅲ, the pedicles were divided. Descriptive statistical method was used to analyze the data. Results: In all cases, restoration of the nasal contour was remarkably good, no flap necrosis occurred. All patients were followed up for 6 months to 2 years, and the appearance and function of the nose recovered well. All patients were satisfied with their final aesthetic results. Conclusions: Three-staged paramedian forehead flap technique ensures maximal blood supply for the lining flap and the inserted cartilage graft, and restores an ideal three-dimensional nasal contour for reconstruction of large full thickness nasal defects.

Emergency surgery comparison of right versus left acute colonic diverticulitis: A 10-year outcome analysis.

INTRODUCTION: The difference in outcome between right (RCD) and left colonic diverticulitis (LCD) is not well established. The aim of this study was to analyse the presentation and surgical outcome of RCD versus left-sided disease following emergency surgery. METHOD: We conducted a retrospective review of patients presenting with acute diverticulitis over a 10-year period from 2004 to 2014 to a tertiary unit. Patient demographics, Hinchey classification, need for emergency surgery, perioperative outcome and recurrence were evaluated. RESULTS: In total 360 patients presented with acute diverticulitis, 218 (61%) were right-sided and 142 (39%) were left-sided. The mean age (57 yrs vs 68 yrs) and median length of stay (4 days vs 5 days) were significantly less in RCD (p < 0.001). The need for emergency surgery was similar between RCD and LCD (30.7% vs 23.2%, p = 0.12). Sixty-seven (31%) patients with RCD required emergency surgery, 42 (62.7%) of these were based on a presumptive diagnosis of appendicitis and underwent laparoscopic appendicectomy only. Operative morbidity (10.4% vs 51.5%, p < 0.001) and mortality were significantly higher in LCD (1.5% v 15.2%, p = 0.007). Subgroup analysis of non-appendicectomy, RCD patients, showed LCD were more likely to require surgery (11.5% vs 23.2%, p = 0.003). There was no difference in recurrence (p = 0.6). CONCLUSION: Right colonic diverticulitis patients are younger and disease course is more benign compared to LCD. Presentation can be confused with appendicitis without proper imaging. In the rare cases where emergency surgery is required, RCD is associated with a lower operative morbidity and mortality compared to left-sided disease.

Porcine dermal collagen mesh (Permacol™) as a bioprosthesis in the ligation of intersphincteric tract (BioLIFT) procedure.

BACKGROUND: Ligation of intersphincteric tract (LIFT) is a sphincter-saving technique used to treat anal fistulas. Incorporation of a bioprosthesis in LIFT (BioLIFT) aims to improve healing. The use of cross-linked porcine dermal collagen mesh Permacol™ in BioLIFT has never been investigated. The aim of this study was to compare the healing rates and outcome of LIFT and BioLIFT for complex anal fistulas using the Permacol™ biological mesh. METHODS: A retrospective analysis of all patients having LIFT or BioLIFT for complex fistulas from January 2010 to November 2019 was performed in a tertiary referral centre. Patient data from a prospectively collected database of all patients having LIFT or BioLIFT were analyzed. RESULTS: LIFT and BioLIFT were performed in 48 (82.8%) and 10 (17.2%) patients, respectively. All BioLIFT patients had previous interventions for their fistulas compared to 30 (62.5%) of patients who had LIFT, p = 0.023. The primary healing rate for LIFT was 87.5% (42/48) compared to 80% (8/10) in BioLIFT, (p = 0.42). Eight (13.8%) patients developed complications, 6 (12.5%) in the LIFT group vs 2 (20%) in the BioLIFT group (p = 0.62). On univariate analysis, the number of previous operations was predictive of complications (p = 0.03). BioLIFT was not associated with complication (OR = 1.75, 95% CI: 0.30-10.3, p = 0.54) or primary healing (OR = 0.57, 95% CI: 0.97-3.36, p = 0.54). There was no significant difference in recurrence (LIFT 12.5% vs BioLIFT 0%, p = 0.58). Kaplan-Meier analysis found no difference in time to recurrence between the two groups (p = 0.65). CONCLUSION: Permacol™ mesh in BioLIFT is feasible and achieves a high primary healing rate of 80%. Prospective evidence is needed to establish the benefits of BioLIFT and determine whether Permacol™ is superior to the non-cross-linked porcine submucosal mesh.

Correction: FOXO3a represses VEGF expression through FOXM1-dependent and -independent mechanisms in breast cancer.

In the published version of this article, the images for cytoplasmic and nuclear FGF7 in MDA-MB-231 cells were duplicated and mistaken for total FGF7 in SKBR-3 and MDA-MB-231 cells.

Calculation of the Hadronic Vacuum Polarization Contribution to the Muon Anomalous Magnetic Moment.

We present a first-principles lattice QCD+QED calculation at physical pion mass of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. The total contribution of up, down, strange, and charm quarks including QED and strong isospin breaking effects is a_{µ}^{HVP LO}=715.4(18.7)×10^{-10}. By supplementing lattice data for very short and long distances with R-ratio data, we significantly improve the precision to a_{µ}^{HVP LO}=692.5(2.7)×10^{-10}. This is the currently most precise determination of a_{µ}^{HVP LO}.

Effect of Ligand Modification on the Mechanism of Electrocatalytic Hydrogen Production by Ni(pyridinethiolate)3- Derivatives.

The effects of ligand modification on the catalytic mechanism of hydrogen production by Ni(PyS)3- derivatives, made with electron-withdrawing and -donating substitutions to the pyridinethiolate (PyS)- ligands, are studied experimentally and computationally using density functional theory. Thermodynamic data, spin density maps, and frontier molecular orbital diagrams were generated for reaction intermediates. Comparison of computed values for E0 and p Ka with experimental values supports the proposed mechanisms. The rate of electrochemical hydrogen production is correlated with the effect of ligand modification. Notably, the presence of an electron-donating substituent favors an alternative mechanism for hydrogen production. Computationally it was determined that the electron-donating substituent causes deviation from the original chemical-electrochemical-chemical-electrochemical (CECE) mechanism of Ni(PyS)3- to a CCEE mechanism, while the CECE mechanism is maintained for all catalysts substituted with electron-withdrawing groups.

Efficacy and tolerability of trastuzumab emtansine in advanced human epidermal growth factor receptor 2-positive breast cancer.

INTRODUCTION: The management of human epidermal growth factor receptor 2 (HER2)-positive breast cancer has changed dramatically with the introduction and widespread use of HER2-targeted therapies. There is, however, relatively limited real-world information about the effectiveness and safety of trastuzumab emtansine (T-DM1) in Hong Kong Chinese patients. We assessed the efficacy and toxicity profiles among local patients with HER2-positive advanced breast cancer who had received T-DM1 therapy in the second-line setting and beyond. METHODS: This retrospective study involved five local centres that provide service for over 80% of the breast cancer population in Hong Kong. The study period was from December 2013 to December 2015. Patients were included if they had recurrent or metastatic histologically confirmed HER2+ breast cancer who had progressed after at least one line of anti-HER2 therapy including trastuzumab. Patients were excluded if they received T-DM1 as first-line treatment for recurrent or metastatic HER2+ breast cancer. Patient charts including biochemical and haematological profiles were reviewed for background information, T-DM1 response, and toxicity data. Adverse events were documented during chemotherapy and 28 days after the last dose of medication. RESULTS: Among 37 patients being included in this study, 28 (75.7%) had two or more lines of anti-HER2 agents and 26 (70.3%) had received two or more lines of palliative chemotherapy. Response assessment revealed that three (8.1%) patients had a complete response, eight (21.6%) a partial response, 11 (29.7%) a stable disease, and 12 (32.4%) a progressive disease; three patients could not be assessed. The median duration of response was 17.3 (95% confidence interval, 8.4-24.8) months. The clinical benefit rate (complete response + partial response + stable disease, ≥12 weeks) was 37.8% (95% confidence interval, 22.2%-53.5%). The median progression-free survival was 6.0 (95% confidence interval, 3.3- 9.8) months and the median overall survival had not been reached by the data cut-off date. Grade 3 or 4 toxicities included thrombocytopaenia (13.5%), raised alanine transaminase (8.1%), anaemia (5.4%), and hypokalaemia (2.7%). No patient died as a result of toxicities. CONCLUSIONS: In patients with HER2-positive advanced breast cancer who have been heavily pretreated with anti-HER2 agents and cytotoxic chemotherapy, T-DM1 is well tolerated and provided a meaningful progression-free survival of 6 months and an overall survival that has not been reached. Further studies to identify appropriate patient subgroups are warranted.

Appropriate timing for surgery after neoadjuvant chemoradiation for esophageal cancer.

Optimal interval between neoadjuvant chemoradiotherapy (CRT) and surgery is not elucidated for esophageal squamous carcinoma. The aim of this study is to evaluate the impact of this time interval on patient outcome. Patients treated with neoadjuvant CRT followed by surgery between 2002 and 2009 were analyzed. Patients were divided into two groups based on the median interval to surgery (64 days): A  64 days (n = 53). A second analysis was performed by re-classifying patients into three interval groups: A* ≤ 40 days (n = 16); B* 41-80 days (n = 60); C* > 80 days (n = 31). Operative outcome, pathological data, and long-term survival were analyzed. One hundred and seven (n = 107) patients were analyzed. Five patients (9.4%) in group B had an anastomotic leak compared with no leakage from group A (P < 0.021). The complete pathological response was comparable in groups A and B (35% vs. 24.5%, p = 0.23). R0 was significantly lower in group A* (A*: 56.3%, B*: 90%, C*: 74.2%, P = 0.006). In patients with R0 resection, 5-year survival was significantly better in group A than B (71.7% vs. 51%, P = 0.032) and in group A* (A* 100% vs. B* 60.2% & C* 48.3%; A* vs. B*, P = 0.036; A* vs. C*, P = 0.019). Complete pathological response was an independent predictor of survival. Early surgery with R0 resection following neoadjuvant CRT may lead to a better outcome. Further prospective studies are still necessary to provide better insight into the issue. At present, timing of surgery should be individualized and performed at the earliest opportunity.

Role of hepatic trisectionectomy in advanced hepatocellular carcinoma.

BACKGROUND: Advanced hepatocellular carcinoma (HCC) with underlying cirrhosis poses a major operative challenge. Patients have a dismal prognosis without curative resection. The role of hepatic trisectionectomy in these patients is not established. The aim of this study was to analyze and compare the perioperative outcome and prognosis of patients undergoing trisectionectomy with hepatic resection of a lesser extent. METHODS: From 2000 to 2014, 48 patients underwent hepatic trisectionectomy for HCC with background cirrhosis or chronic hepatitis (Group A). Another (Group B) 520 patients underwent liver resection of a lesser extent. Patient demographics, clinicopathological data, perioperative outcome and long-term survival were compared between the 2 groups. RESULTS: Intraoperative bloodloss, operating time and total hospital stay were significantly higher in trisectionectomy patients. Tumors were larger and more advanced in group A. The morbidity rate was 43.8% in group A compared to 27.5% in group B, p = 0.027. In-hospital mortality was 6.3% for group A. Group A had a significantly shorter time to recurrence (4.5months vs 6.2months, p = 0.036), as well as a poorer disease-free survival (DFS) than group B (6.3 months vs 15.7 months, p = 0.02). Overall survival was comparable. Tumor number, size, albumin, INR, microvascular invasions and positive resection margins were predictors of disease-free survival. CONCLUSION: Hepatic trisectionectomy may be associated with a higher morbidity and lower DFS. However, these patients would not be suitable candidates for ablative therapy or liver transplantation. With careful patient selection and meticulous surgical technique, trisectionectomy is feasible and gives these patients the only hope of cure.

Comparing the meanings of living with advanced breast cancer between women resilient to distress and women with persistent distress: a qualitative study.

BACKGROUND: Most women with advanced breast cancer (ABC) show little distress, but about one in ten show persistent distress over time. It remains unclear if meanings ascribed by patients to ABC differentiate these distress trajectories. STUDY AIMS: This qualitative study (a) compared illness meanings of ABC between women with persistent psychological distress and those with low/transient distress, and (b) examined how illness meanings might influence coping strategies. METHODS: The sample was drawn from a prior quantitative study exploring psychological distress trajectories following ABC diagnosis. Overall, 42 Cantonese- or Mandarin-speaking Chinese women diagnosed with locally advanced or metastatic ABC were recruited based on their distress trajectory status (low-stable, transient, or persistent distress). Interviews were recorded, transcribed, and analyzed following grounded theory approach using simultaneous analysis. RESULTS: Women with persistent distress viewed their diagnosis as another blow in life, the illness was global, permeating every aspect of their life. Maladaptive rumination and thought suppression were common responses to illness demands. These women had poor social support. A sense of demoralization stood out in their narratives. In contrast, women with transient/low-stable distress encapsulated the illness, with minimum impacts of their life. They did not evidence dysfunctional repetitive thoughts. Living in a supportive environment, they were able to accept and/or live in the present-moment. CONCLUSIONS: Rumination, thought suppression, social constraints, and pre-existing exposure to life stress may be potential risks for chronic distress in response to advanced breast cancer. Persistent and transient distress responses to cancer may have different underpinnings. Copyright © 2016 John Wiley & Sons, Ltd.

The multifactorial aetiology of fracture nonunion and the importance of searching for latent infection.

OBJECTIVES: A successful outcome following treatment of nonunion requires the correct identification of all of the underlying cause(s) and addressing them appropriately. The aim of this study was to assess the distribution and frequency of causative factors in a consecutive cohort of nonunion patients in order to optimise the management strategy for individual patients presenting with nonunion. METHODS: Causes of the nonunion were divided into four categories: mechanical; infection; dead bone with a gap; and host. Prospective and retrospective data of 100 consecutive patients who had undergone surgery for long bone fracture nonunion were analysed. RESULTS: A total of 31% of patients had a single attributable cause, 55% had two causes, 14% had three causes and 1% had all four. Of those (31%) with only a single attributable cause, half were due to a mechanical factor and a quarter had dead bone with a gap. Mechanical causation was found in 59% of all patients, dead bone and a gap was present in 47%, host factors in 43% and infection was a causative factor in 38% of patients.In all, three of 58 patients (5%) thought to be aseptic and two of nine (22%) suspected of possible infection were found to be infected. A total of 100% of previously treated patients no longer considered to have ongoing infection, had multiple positive microbiology results. CONCLUSION: Two thirds of patients had multiple contributing factors for their nonunion and 5% had entirely unexpected infection. This study highlights the importance of identifying all of the aetiological factors and routinely testing tissue for infection in treating nonunion. It raises key points regarding the inadequacy of a purely radiographic nonunion classification system and the variety of different definitions for atrophic nonunion in the current mainstream classifications used for nonunion.Cite this article: L. Mills, J. Tsang, G. Hopper, G. Keenan, A. H. R. W. Simpson. The multifactorial aetiology of fracture nonunion and the importance of searching for latent infection. Bone Joint Res 2016;5:512-519. DOI: 10.1302/2046-3758.510.BJR-2016-0138.

OTUB1 inhibits the ubiquitination and degradation of FOXM1 in breast cancer and epirubicin resistance.

The forkhead transcription factor FOXM1 has a key role in DNA damage response, and its deregulated overexpression is associated with genotoxic drug resistance in breast cancer. However, little is known about the posttranslational mechanisms by which FOXM1 expression is regulated by genotoxic agents and how they are deregulated in resistant cells. Initial co-immunoprecipitation studies verified previous proteomic analysis finding that the OTUB1 is a novel FOXM1-interacting protein. Western blot analysis showed that both OTUB1 and FOXM1 expression reduced upon genotoxic agent treatment in MCF-7 cells, but remained relatively constant in resistant cells. FOXM1 expression reduced upon OTUB1 depletion by siRNA and increased with OTUB1 overexpression in MCF-7 cells, arguing that OTUB1 positively regulates FOXM1 expression. In agreement, co-immunoprecipitation experiments demonstrated that FOXM1 expression is associated with OTUB1 binding but inversely correlates with conjugation to the protein degradation-associated Lys-48-linked ubiquitin-chains. Overexpression of wild-type (WT) OTUB1, but not the OTUB1(C91S) mutant, disrupted the formation of Lys48-linked ubiquitin-conjugates on FOXM1. Importantly, knockdown of OTUB1 by siRNA resulted in an increase in turnover of FOXM1 in MCF-7 cells treated with the protein synthesis inhibitor cycloheximide, whereas overexpression of WT OTUB1, but not the OTUB1(C91S) mutant, significantly enhances the half-life of FOXM1. In addition, proliferative and clonogenic assays also show that OTUB1 can enhance the proliferative rate and epirubicin resistance through targeting FOXM1, as OTUB1 has little effect on FOXM1-deficient cells. The physiological relevance of the regulation of FOXM1 by OTUB1 is further underscored by the significant correlations between FOXM1 and OTUB1 expression in breast cancer patient samples. Cox-regression survival analysis indicates that OTUB1 overexpression is linked to poorer outcome in particular in patients treated with chemotherapy. Collectively, these data suggest that OTUB1 limits the ubiquitination and degradation of FOXM1 in breast cancer and has a key role in genotoxic agent resistance.

Paclitaxel targets FOXM1 to regulate KIF20A in mitotic catastrophe and breast cancer paclitaxel resistance.

FOXM1 has been implicated in taxane resistance, but the molecular mechanism involved remains elusive. In here, we show that FOXM1 depletion can sensitize breast cancer cells and mouse embryonic fibroblasts into entering paclitaxel-induced senescence, with the loss of clonogenic ability, and the induction of senescence-associated ß-galactosidase activity and flat cell morphology. We also demonstrate that FOXM1 regulates the expression of the microtubulin-associated kinesin KIF20A at the transcriptional level directly through a Forkhead response element (FHRE) in its promoter. Similar to FOXM1, KIF20A expression is downregulated by paclitaxel in the sensitive MCF-7 breast cancer cells and deregulated in the paclitaxel-resistant MCF-7Tax(R) cells. KIF20A depletion also renders MCF-7 and MCF-7Tax(R) cells more sensitive to paclitaxel-induced cellular senescence. Crucially, resembling paclitaxel treatment, silencing of FOXM1 and KIF20A similarly promotes abnormal mitotic spindle morphology and chromosome alignment, which have been shown to induce mitotic catastrophe-dependent senescence. The physiological relevance of the regulation of KIF20A by FOXM1 is further highlighted by the strong and significant correlations between FOXM1 and KIF20A expression in breast cancer patient samples. Statistical analysis reveals that both FOXM1 and KIF20A protein and mRNA expression significantly associates with poor survival, consistent with a role of FOXM1 and KIF20A in paclitaxel action and resistance. Collectively, our findings suggest that paclitaxel targets the FOXM1-KIF20A axis to drive abnormal mitotic spindle formation and mitotic catastrophe and that deregulated FOXM1 and KIF20A expression may confer paclitaxel resistance. These findings provide insights into the underlying mechanisms of paclitaxel resistance and have implications for the development of predictive biomarkers and novel chemotherapeutic strategies for paclitaxel resistance.