Contemporary dental student professionalism: moving towards a macro-level perspective

Defining professionalism and developing educational interventions that foster and assess student professionalism are integral to dental education. Nevertheless, conceptual, methodological and pedagogic differences define the academic field, leaving students, educators and the profession itself struggling to make meaningful progress on how best to elicit and monitor dental student professionalism. This article proposes that more progress can be made on this important issue when a contextualised, sociological assessment of dentistry and dental professionalism is undertaken. We contend that identifying some of the socio-cultural demands in UK dental students' lives, and acknowledging how these pressures shape their interactions with the UK dental education system, provides a nuanced and contemporaneous understanding of what it means to be an oral health care professional at a time of social and health care upheaval. Dental educators can use this insight to work towards being more understanding of and responsive to dental student professional development.

Does intrathecal baclofen alter the natural history of hip displacement?

This commentary is on the original article by Asma et al. on pages 1112–1117 of this issue.

The use of botulinum toxin and intrathecal baclofen in hip dysplasia in cerebral palsy

This letter to the editor is on the original article by Asma et al. on pages 1112–1117 and the letters to the editor by Graham et al. on page 1123 and Howard and Shrader on page 1124 of this issue.

An observational analysis of risk factors associated with symptomatic third molar teeth

BACKGROUND

Third molar teeth (wisdom teeth) are a common cause of pain and infection in young adults. The study aimed to describe the prevalence of symptomatic third molar teeth and identify factors which predispose to third molar symptoms in a birth cohort.

METHODS

An observational study was undertaken nested in the Avon Longitudinal Study of Parents and Children (ALSPAC), a birth cohort based in south west England. The main outcomes were self-reported third molar pain, swelling and treatment for third molar problems, taken from questionnaires completed at age 23 years. The exposures including sex, dental history, socioeconomic status, diet, and genetic factors were obtained from earlier ALSPAC data.

RESULTS

In total 4,222 ALSPAC participants responded to one or more questions about third molar teeth. The final sample included more female participants than male participants. The majority of participants (56.6%) reported at least one episode of pain associated with their third molars. Females had greater odds than males of reporting swelling (adjusted odds ratio (OR) 1.97; 95%confidence interval (CI) 1.56, 2.51), pain (adjusted OR=1.96; 95%CI 1.56, 2.51) and receiving both non-surgical and surgical treatment (adjusted OR=2.30; 95%CI 1.62, 3.35, adjusted OR=1.54; 95%CI 1.17, 2.06 respectively). Participants with previously filled teeth had greater odds of third molar extraction. There were no strong associations between index of multiple deprivation (IMD) score or sugar intake and the third molar outcomes. There was weak evidence for a genetic contribution to third molar pain.

CONCLUSIONS

Symptomatic third molars are common in this age group, with over half of the participants reporting pain or other symptoms. Female participants had greater odds for third molar pain, swelling and treatment.

Treatment of pediatric spasticity, including children with cerebral palsy, with Botox (onabotulinumtoxinA): Development, insights, and impact

Spasticity is a velocity-dependent increase in muscle tone that has a negative effect on quality of life and hinders the ability of others to provide care. In children, most cases are caused by cerebral palsy. Traditionally, many children are treated with surgery, sometimes performed before their limbs had grown sufficiently to permit long-term success. Nonsurgical treatment comprises oral pharmacological options, but their efficacy is limited and side effects such as drowsiness and decreased short-term memory are common; nerve block procedures can cause painful dysesthesias and muscle scarring. OnabotulinumtoxinA was first approved for the treatment of pediatric lower limb spasticity in Europe in the 1990s and is now licensed for use in pediatric patients in over 80 countries worldwide, based on a large body of clinical evidence demonstrating its efficacy and safety. In 2019 the U.S. Food and Drug Administration approved onabotulinumtoxinA for the treatment of pediatric patients with upper or lower limb spasticity. This approval represents 3 decades of work to refine the dose, measurements, patient selection, and muscle selection. The availability of onabotulinumtoxinA as a treatment for pediatric spasticity can have a substantial impact on a patient's quality of life. The use of onabotulinumtoxinA in combination with orthoses and occupational/physical therapy can postpone corrective surgery until growth is nearly complete and minimize the number of corrective surgeries.

Evaluating the effect of metabolic traits on oral and oropharyngeal cancer risk using Mendelian randomization

A recent World Health Organization report states that at least 40% of all cancer cases may be preventable, with smoking, alcohol consumption, and obesity identified as three of the most important modifiable lifestyle factors. Given the significant decline in smoking rates, particularly within developed countries, other potentially modifiable risk factors for head and neck cancer warrant investigation. Obesity and related metabolic disorders such as type 2 diabetes (T2D) and hypertension have been associated with head and neck cancer risk in multiple observational studies. However, adiposity has also been correlated with smoking, with bias, confounding or reverse causality possibly explaining these findings. To overcome the challenges of observational studies, we conducted two-sample Mendelian randomization (inverse variance weighted [IVW] method) using genetic variants which were robustly associated with adiposity, glycaemic and blood pressure traits in genome-wide association studies (GWAS). Outcome data were taken from the largest available GWAS of 6034 oral and oropharyngeal cases, with 6585 controls. We found limited evidence of a causal effect of genetically proxied body mass index (BMI; OR IVW = 0.89, 95% CI 0.72-1.09, p = 0.26 per 1 standard deviation in BMI [4.81kg/m2]) on oral and oropharyngeal cancer risk. Similarly, there was limited evidence for related traits including T2D and hypertension. Small effects cannot be excluded given the lack of power to detect them in currently available GWAS.

Case series of medication-related osteonecrosis of the jaw (MRONJ) patients prescribed a drug holiday

The role of a drug holiday in the management of medication-related osteonecrosis of the jaw (MRONJ) remains controversial. Current UK guidance does not recommend this practice given the lack of conclusive evidence, and potential risk of skeletal-related events or cancer metastasis. This paper aims to describe a series of fifty patients with confirmed MRONJ who were prescribed a drug holiday as part of their management. Data were collected on exposures including: anti-resorptive and/or anti-angiogenic drug history, duration of drug, method of administration, concurrent therapy, MRONJ stage, management of MRONJ and duration of drug holiday. The primary outcome was complete healing as documented in the clinical notes. Multivariate Cox regression analysis was performed to evaluate the association between exposures and primary MRONJ outcome. Models were adjusted for age, sex, and index of multiple deprivation. Survival analysis was performed using a log-rank test, censoring any patients with no primary outcome recorded (p < 0.05). A total of 44% of patients stopped their medication for >36 months. Over half of all MRONJ cases presented in the posterior mandible and dental extraction was the most common precipitating factor (76%). Almost three-quarters (72%) of patients achieved complete healing. MRONJ recurrence (new site) was reported at 30%, mainly in those with incomplete healing of the initial area. There was a lack of evidence for an association between all recorded exposures and the primary MRONJ outcome using multivariate Cox regression. Similarly, we did not demonstrate evidence for an association between the duration of the drug holiday and MRONJ outcome. Our results support published guidelines, which do not recommend the discontinuation of bone modifying drugs for the prevention of MRONJ, or as part of treatment for established MRONJ.

An update on oral cavity cancer: epidemiological trends, prevention strategies and novel approaches in diagnosis and prognosis

In the UK, the incidence of oral cavity cancer continues to rise, with an increase of around 60% over the past 10 years. Many patients still present with advanced disease, often resulting in locoregional recurrence and poor outcomes, which has not changed significantly for over four decades. Changes in aetiology may also be emerging, given the decline of smoking in developed countries. Therefore, new methods to better target prevention, improve screening and detect recurrence are needed. High-throughput 'omics' technologies appear promising for future individual-level diagnosis and prognosis. However, given this is a relatively rare cancer with significant intra-tumour heterogeneity and variation in patient response, reliable biomarkers have been difficult to elucidate. From a public health perspective, implementing these novel technologies into current services would require substantial practical, financial and ethical considerations. This may be difficult to justify and implement at present, therefore focus remains on early detection using new patient-led follow-up strategies. This paper reviews the latest evidence on epidemiological trends in oral cavity cancer to help identify at risk groups, population-based approaches for prevention, in addition to potential cutting-edge approaches in the diagnosis and prognosis of this disease.

Metabolic disorders and the risk of head and neck cancer: a protocol for a systematic review and meta-analysis

INTRODUCTION

Head and neck cancer squamous cell carcinoma (HNSCC) is the sixth most common cancer internationally. Established risk factors include smoking, alcohol and presence of human papillomavirus (HPV). The incidence rate of new disease continues to rise, despite falls in alcohol consumption and a reduction in smoking, the rising rates are unlikely to be solely attributed to HPV status alone. Obesity and its associated conditions such as type 2 diabetes (T2D) are implicated in the risk and progression of a variety of cancers, but there is paucity of evidence regarding its role in HNSCC.

METHODS AND ANALYSIS

A systematic review of cohort studies, reporting a risk of incident HNSCC, will be included. A systematic search strategy has been developed, multiple databases will be searched from January 1966 to November 2021, including Cochrane Library, OVID SP versions of Medline and EMBASE. The primary outcome will be incident HNSCC based on exposures of T2D, obesity, dyslipidaemia and hypertension as defined by the WHO. A combined risk effect across studies will be calculated using meta-analysis, although depending on the heterogeneity in study design, exposure and outcome reporting this may not be possible.

ETHICS AND DISSEMINATION

No ethical approval is required for this systematic review. The review will be published in a relevant peer-review journal and findings will be presented at scientific meetings in both poster and oral presentation form.

PROSPERO REGISTRATION NUMBER DETAILS

This study has been registered with the International Prospective Register of Systematic Reviews (PROSPERO) with study registration number CRD42021250520. This protocol has been developed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidance statement.

A clinical observational analysis of aerosol emissions from dental procedures

Aerosol generating procedures (AGPs) are defined as any procedure releasing airborne particles <5 μm in size from the respiratory tract. There remains uncertainty about which dental procedures constitute AGPs. We quantified the aerosol number concentration generated during a range of periodontal, oral surgery and orthodontic procedures using an aerodynamic particle sizer, which measures aerosol number concentrations and size distribution across the 0.5-20 μm diameter size range. Measurements were conducted in an environment with a sufficiently low background to detect a patient's cough, enabling confident identification of aerosol. Phantom head control experiments for each procedure were performed under the same conditions as a comparison. Where aerosol was detected during a patient procedure, we assessed whether the size distribution could be explained by the non-salivary contaminated instrument source in the respective phantom head control procedure using a two-sided unpaired t-test (comparing the mode widths (log(σ)) and peak positions (DP,C)). The aerosol size distribution provided a robust fingerprint of aerosol emission from a source. 41 patients underwent fifteen different dental procedures. For nine procedures, no aerosol was detected above background. Where aerosol was detected, the percentage of procedure time that aerosol was observed above background ranged from 12.7% for ultrasonic scaling, to 42.9% for 3-in-1 air + water syringe. For ultrasonic scaling, 3-in-1 syringe use and surgical drilling, the aerosol size distribution matched the non-salivary contaminated instrument source, with no unexplained aerosol. High and slow speed drilling produced aerosol from patient procedures with different size distributions to those measured from the phantom head controls (mode widths log(σ)) and peaks (DP,C, p< 0.002) and, therefore, may pose a greater risk of salivary contamination. This study provides evidence for sources of aerosol generation during common dental procedures, enabling more informed evaluation of risk and appropriate mitigation strategies.

An observational analysis of risk factors associated with symptomatic third molar teeth

Background: Third molar teeth (wisdom teeth) are a common cause of pain and infection in young adults. The study aimed to describe the prevalence of symptomatic third molar teeth and identify factors which predispose to third molar symptoms in a birth cohort. Methods: An observational study was undertaken nested in the Avon Longitudinal Study of Parents and Children (ALSPAC), a birth cohort based in south west England. The main outcomes were self-reported third molar pain, swelling and treatment for third molar problems, taken from questionnaires completed at age 23 years. The exposures including sex, dental history, socioeconomic status, diet, and genetic factors were obtained from earlier ALSPAC data. Results: In total 4,222 ALSPAC participants responded to one or more questions about third molar teeth. The final sample included more female participants than male participants. The majority of participants (56.6%) reported at least one episode of pain associated with their third molars. Females had greater odds than males of reporting swelling (adjusted odds ratio (OR) 1.97; 95%confidence interval (CI) 1.56, 2.51), pain (adjusted OR=1.96; 95%CI 1.56, 2.51) and receiving both non-surgical and surgical treatment (adjusted OR=2.30; 95%CI 1.62, 3.35, adjusted OR=1.54; 95%CI 1.17, 2.06 respectively). Participants with previously filled teeth had greater odds of third molar extraction. There were no strong associations between index of multiple deprivation (IMD) score or sugar intake and the third molar outcomes. There was weak evidence for a genetic contribution to third molar pain. Conclusions: Symptomatic third molars are common in this age group, with over half of the participants reporting pain or other symptoms. Female participants had greater odds for third molar pain, swelling and treatment.

Investigating the effect of sexual behaviour on oropharyngeal cancer risk: a methodological assessment of Mendelian randomization

BACKGROUND

Human papilloma virus infection is known to influence oropharyngeal cancer (OPC) risk, likely via sexual transmission. However, sexual behaviour has been correlated with other risk factors including smoking and alcohol, meaning independent effects are difficult to establish. We aimed to evaluate the causal effect of sexual behaviour on the risk of OPC using Mendelian randomization (MR).

METHODS

Genetic variants robustly associated with age at first sex (AFS) and the number of sexual partners (NSP) were used to perform both univariable and multivariable MR analyses with summary data on 2641 OPC cases and 6585 controls, obtained from the largest available genome-wide association studies (GWAS). Given the potential for genetic pleiotropy, we performed a number of sensitivity analyses: (i) MR methods to account for horizontal pleiotropy, (ii) MR of sexual behaviours on positive (cervical cancer and seropositivity for Chlamydia trachomatis) and negative control outcomes (lung and oral cancer), (iii) Causal Analysis Using Summary Effect estimates (CAUSE), to account for correlated and uncorrelated horizontal pleiotropic effects, (iv) multivariable MR analysis to account for the effects of smoking, alcohol, risk tolerance and educational attainment.

RESULTS

In univariable MR, we found evidence supportive of an effect of both later AFS (IVW OR = 0.4, 95%CI (0.3, 0.7), per standard deviation (SD), p = < 0.001) and increasing NSP (IVW OR = 2.2, 95%CI (1.3, 3.8) per SD, p = < 0.001) on OPC risk. These effects were largely robust to sensitivity analyses accounting for horizontal pleiotropy. However, negative control analysis suggested potential violation of the core MR assumptions and subsequent CAUSE analysis implicated pleiotropy of the genetic instruments used to proxy sexual behaviours. Finally, there was some attenuation of the univariable MR results in the multivariable models (AFS IVW OR = 0.7, 95%CI (0.4, 1.2), p = 0.21; NSP IVW OR = 0.9, 95%CI (0.5 1.7), p = 0.76).

CONCLUSIONS

Despite using genetic variants strongly related sexual behaviour traits in large-scale GWAS, we found evidence for correlated pleiotropy. This emphasizes a need for multivariable approaches and the triangulation of evidence when performing MR of complex behavioural traits.

Efficacy and safety of onabotulinumtoxinA with standardized occupational therapy for treatment of pediatric upper limb spasticity: Phase III placebo-controlled randomized trial

BACKGROUND:

This is the first large study of onabotulinumtoxinA as treatment for pediatric upper limb spasticity.

OBJECTIVE:

Evaluate efficacy and safety of a single treatment with onabotulinumtoxinA plus occupational therapy (OT).

METHODS:

In this registrational phase III, multinational study (NCT01603602), participants were randomized 1:1:1 to onabotulinumtoxinA 3 U/kg/OT, 6 U/kg/OT, or placebo/OT. Primary endpoint was average change from baseline at weeks 4 and 6 in Modified Ashworth Scale-Bohannon (MAS) score. Secondary endpoints included Modified Tardieu Scale (MTS), Clinical Global Impression of Change (CGI) and functional Goal Attainment Scale (GAS).

RESULTS:

235 participants were randomized. At weeks 4 and 6, onabotulinumtoxinA groups had greater mean reductions in MAS (both –1.9; p < 0.001) versus placebo (–1.2). OnabotulinumtoxinA doses improved dynamic tone per MTS. Mean CGI at weeks 4 and 6 was unchanged in the overall population, but improved in a post hoc analysis of patients with a single affected upper limb (UL) muscle group (elbow or wrist). GAS score for passive goals was significantly higher for 6 U/kg versus placebo at week 12. Most AEs were mild/moderate in severity; overall incidence was similar between groups.

CONCLUSIONS:

OnabotulinumtoxinA (3 and 6 U/kg) was safe and effective in reducing upper limb spasticity in pediatric participants.

Exploring the impact of digital professionalism awareness training on dental undergraduate students

INTRODUCTION

Since the publication of GDC guidance, there have been small, but rising numbers of Fitness to Practise (FtP) cases made against qualified dentists, relating to the use of social media. Prior to graduation, dental students currently receive training in the appropriate use of social media, but more work is needed to determine the most effective methods do this. The aim of this study is to explore the impact of the digital professionalism awareness training provided at one UK-based institution.

MATERIALS AND METHODS

In year 2, a "brown envelope" is compiled using an online publicly available Facebook profile search for every student. All year 2 to 5 dental undergraduate students at one UK dental school who had completed the "brown envelope" were invited to participate in focus groups to examine its impact on behaviour change. A qualitative framework analysis method was applied to the transcripts.

RESULTS

Eleven dental undergraduate students participated in two focus groups. All students had experienced the "brown envelope" intervention. Four main themes emerged, including: a clear expression of dental student autonomy and rejection of regulation; that online activity in dentistry is different to medicine; that the intervention is useful and changed online behaviour; and constructive suggestions for improving training.

CONCLUSION

The interactive "brown envelope" intervention for digital professionalism awareness training was well received and appeared to result in actionable behavioural change on student profiles (eg alterations in privacy settings or restricting access to their own "friends lists").

Using genetic variants to evaluate the causal effect of cholesterol lowering on head and neck cancer risk: A Mendelian randomization study

Head and neck squamous cell carcinoma (HNSCC), which includes cancers of the oral cavity and oropharynx, is a cause of substantial global morbidity and mortality. Strategies to reduce disease burden include discovery of novel therapies and repurposing of existing drugs. Statins are commonly prescribed for lowering circulating cholesterol by inhibiting HMG-CoA reductase (HMGCR). Results from some observational studies suggest that statin use may reduce HNSCC risk. We appraised the relationship of genetically-proxied cholesterol-lowering drug targets and other circulating lipid traits with oral (OC) and oropharyngeal (OPC) cancer risk using two-sample Mendelian randomization (MR). For the primary analysis, germline genetic variants in HMGCR, NPC1L1, CETP, PCSK9 and LDLR were used to proxy the effect of low-density lipoprotein cholesterol (LDL-C) lowering therapies. In secondary analyses, variants were used to proxy circulating levels of other lipid traits in a genome-wide association study (GWAS) meta-analysis of 188,578 individuals. Both primary and secondary analyses aimed to estimate the downstream causal effect of cholesterol lowering therapies on OC and OPC risk. The second sample for MR was taken from a GWAS of 6,034 OC and OPC cases and 6,585 controls (GAME-ON). Analyses were replicated in UK Biobank, using 839 OC and OPC cases and 372,016 controls and the results of the GAME-ON and UK Biobank analyses combined in a fixed-effects meta-analysis. We found limited evidence of a causal effect of genetically-proxied LDL-C lowering using HMGCR, NPC1L1, CETP or other circulating lipid traits on either OC or OPC risk. Genetically-proxied PCSK9 inhibition equivalent to a 1 mmol/L (38.7 mg/dL) reduction in LDL-C was associated with an increased risk of OC and OPC combined (OR 1.8 95%CI 1.2, 2.8, p = 9.31 x10-05), with good concordance between GAME-ON and UK Biobank (I2 = 22%). Effects for PCSK9 appeared stronger in relation to OPC (OR 2.6 95%CI 1.4, 4.9) than OC (OR 1.4 95%CI 0.8, 2.4). LDLR variants, resulting in genetically-proxied reduction in LDL-C equivalent to a 1 mmol/L (38.7 mg/dL), reduced the risk of OC and OPC combined (OR 0.7, 95%CI 0.5, 1.0, p = 0.006). A series of pleiotropy-robust and outlier detection methods showed that pleiotropy did not bias our findings. We found limited evidence for a role of cholesterol-lowering in OC and OPC risk, suggesting previous observational results may have been confounded. There was some evidence that genetically-proxied inhibition of PCSK9 increased risk, while lipid-lowering variants in LDLR, reduced risk of combined OC and OPC. This result suggests that the mechanisms of action of PCSK9 on OC and OPC risk may be independent of its cholesterol lowering effects; however, this was not supported uniformly across all sensitivity analyses and further replication of this finding is required.

Abstract PS13-40: Real-world outcomes in patients receiving neo-adjuvant chemotherapy for early-stage breast cancer

Background: Real-world data on characteristics, outcomes, and toxicity in patients with early breast cancer (EBC) receiving neo-adjuvant chemotherapy (NACT) is lacking. This study characterises experience of NACT in a single UK NHS specialist oncology centre.

Methods: Retrospective case note review of sequential patients with EBC treated with NACT between April 2013 and Sept 2019. Treatment regimens, toxicity data, pathological response (PathCR, defined as no residual invasive tumour in the breast and lymph nodes), recurrence-free survival (RFS) and overall survival (OS) were compared between groups according to baseline characteristics and tumour subtype, defined by oestrogen receptor (ER) and HER2 status.

Results: 405 patients (median age 52 years (IQR 45–61)) were included with a median follow up of 36.4 months. At diagnosis most (253 (62%)) were symptomatic, 368 (91%) had invasive ductal carcinoma, 19 (5%) invasive lobular carcinoma and 18 (4%) inflammatory, spindle or mixed histology. Most were pre-NACT stage 2 or above (Stage 1 - 12 (3%), Stage 2a - 129 (32%), Stage 2b 148 (37%), Stage 3a - 73 (18%), Stage 3b – 25 (6%), Stage 3c -14 (3%)) with no clear trend in stage by year of diagnosis or disease subtype and overall 244 (60%) were node positive pre-NACT. 99% had grade 2 or grade 3 cancer; 320 patients (79%) had Ki-67 &gt;15% and 72 patients (18%) had Ki-67 &lt;15%. 392 (96.8%) patients received primary prophylaxis with Granulocyte-Colony Stimulating Factor (GCSF) and 327 patients (76.9%) received an anthracycline-taxane (AT) containing schedule. There were few dose delays due to toxicity (no delay 353 (87%) v delay 51 (13%)) however, 187 (46%) had one or more dose reductions which was significantly more common in patients &gt;61 years (Odds Ratio (OR) v patients &lt;45 years 1.32, 95% (CI 1.10-1.58,P=0.003). PathCR rates did not significantly vary by year of treatment, tumour size or nodal stage but did vary by subtype: ER+/HER2- 8/128 (6.25%), ER+/HER2+ 34/111 (30.6%), ER-/HER2+ 42/69 (60.9%), ER-/HER2- 32/97 (33%). PathCR was predictive of RFS: recurrence occurred in ER+/HER2- pathCR 0/8 (0%) v non-pathCR 24/120 (20%), ER+/HER2+ 0/34 (0%) v 7/77 (9.1%), ER-/HER2+ 4/42 (9.5%) v 6/27 (22%) and ER-/HER2- 4/32 (12.5%) v 21/65 (32%). There was a non-significant trend towards improved pathCR with the addition of platinum (P) to AT in ER-/HER2- disease (19/43 (44.2%) v 11/41 (26.8%) respectively, OR 2.16 (95% CI 0.86-5.40, p=0.09). In HER2+ disease, the addition of pertuzumab (P) to trastuzumab (H) with AT chemotherapy did not increase pathCR rates. At time of analysis 10% of patients had died precluding meaningful analysis of OS by response. Ki-67, Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) had no significant associations with pathCR.

Conclusions: Real-world outcomes from NACT at a single UK centre are consistent with published randomised data for pathCR rates by tumour subtype. Despite 96.8% of patients receiving GCSF almost half had at least one dose reduction, potentially compromising dose intensity. Whilst this retrospective analysis must be interpreted with caution, as expected there was a trend toward improved response with the addition of platinum in ER-/HER2- disease but an interesting lack of further pathCR when adding pertuzumab in HER2 positive disease. Further analyses will be presented including site of recurrence, type of surgery by response, radiotherapy treatment given and multi-variate analysis.

Citation Format: Catherine McDonald, Rebecca Squires, Mark Gormley, Ryan Langdon, Ann Archer, Jessica Ball, Georgina Gullick, Chloe Caws, John Boardman, Vivek Mohan, Amit Bahl, Jessica Jenkins, Charles Comins, Lara Gibbs, Jeremy Braybrooke, Timothy Robinson. Real-world outcomes in patients receiving neo-adjuvant chemotherapy for early-stage breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-40.

A multivariable Mendelian randomization analysis investigating smoking and alcohol consumption in oral and oropharyngeal cancer

The independent effects of smoking and alcohol in head and neck cancer are not clear, given the strong association between these risk factors. Their apparent synergistic effect reported in previous observational studies may also underestimate independent effects. Here we report multivariable Mendelian randomization performed in a two-sample approach using summary data on 6,034 oral/oropharyngeal cases and 6,585 controls from a recent genome-wide association study. Our results demonstrate strong evidence for an independent causal effect of smoking on oral/oropharyngeal cancer (IVW OR 2.6, 95% CI = 1.7, 3.9 per standard deviation increase in lifetime smoking behaviour) and an independent causal effect of alcohol consumption when controlling for smoking (IVW OR 2.1, 95% CI = 1.1, 3.8 per standard deviation increase in drinks consumed per week). This suggests the possibility that the causal effect of alcohol may have been underestimated. However, the extent to which alcohol is modified by smoking requires further investigation.

Litigation risks despite guideline adherence for acute spinal cord injury: time is spine

OBJECTIVE

Current guidelines do not specify timing for management of acute spinal cord injury (aSCI) due to lack of high-quality evidence supporting specific intervals for intervention. Randomized prospective trials may be unethical. Nonetheless, physicians have been sued for delays in diagnosis and intervention.

METHODS

The authors reviewed both the medical literature supporting the guidelines and the legal cases reported in the Westlaw and Lexis Advance databases from 1972 to 2018 resulting in awards or settlements, to identify whether surgeons are vulnerable to litigation despite the existence of guidelines not mandating specific timing of care.

RESULTS

Timing of intervention was related to claims in 59 (36%) of 163 cases involving SCI. All 22 trauma cases identified cited timing of intervention, sometimes related to delayed diagnosis, as a reason for the lawsuit. The mean award of 10 cases in which the plaintiffs' awards were disclosed was $4,294,384. In the majority of cases, award amounts were not disclosed.

CONCLUSIONS

Because conduct of a prospective, randomized trial to investigate surgical timing of intervention for aSCI may not be achievable, evidence-based guidelines will be unlikely to mandate specific timing. Nonetheless, surgeons who unreasonably delay intervention for aSCI may be at risk for litigation due to treatment delay. This is increasingly likely in an environment where "complete" SCI is difficult to verify. SCI may at some point be recognized as a surgical emergency, as brain injury generally is, despite a lack of prospective randomized trials supporting this implementation, challenging the feasibility of the US trauma infrastructure to provide care for these patients.

Efficacy of Repeat AbobotulinumtoxinA (Dysport®) Injections in Improving Gait in Children with Spastic Cerebral Palsy

Purpose: This secondary analysis of a randomized, double-blind study plus open-label extension (NCT01249417/NCT01251380) evaluated the efficacy of abobotulinumtoxinA versus placebo in improving gait pattern in children with dynamic equinus due to cerebral palsy (CP) as assessed by the observational gait scale (OGS). Methods: Ambulatory children with CP (N = 241, aged 2-17) and dynamic equinus were randomized to treatment with abobotulinumtoxinA (10 or 15U/kg/leg) or placebo injected into the gastrocsoleus. All children received abobotulinumtoxinA in the open-label phase. Results: In the double-blind phase, abobotulinumtoxinA significantly improved OGS total scores versus placebo at Week 4 (treatment effect vs. placebo: 10U/kg/leg: 1.5 [0.7, 2.3], p = .0003; 15U/kg/leg: 1.1 [0.3, 1.9], p = .01). In the open-label phase, treatment with abobotulinumtoxinA continued to improve the OGS score at the same magnitude as seen in the double-blind study. Conclusion: Repeat treatment with abobotulinumtoxinA improved gait in children with dynamic equinus.

A conventional surgical approach for removal of an ectopic tooth in the nasal cavity

A 40-year-old female patient presented to ears, nose and throat complaining of cacosmia and discharge from the left maxillary sinus. Her CT scan revealed an ectopic supplemental nasal tooth which could not be removed by nasoendoscopy. Therefore, a conventional intraoral surgical approach was taken. In this case, we discuss the indications for conventional surgical removal of teeth from the nasal cavity when a nasoendoscopic approach is not possible. We highlight the potential pitfalls of both conventional and nasoendoscopic approaches, including some essential considerations when treatment planning these cases.

A prospective genome-wide study of prostate cancer metastases reveals association of wnt pathway activation and increased cell cycle proliferation with primary resistance to abiraterone acetate-prednisone

Background

Genomic aberrations have been identified in metastatic castration-resistant prostate cancer (mCRPC), but molecular predictors of resistance to abiraterone acetate/prednisone (AA/P) treatment are not known.

Patients and methods

In a prospective clinical trial, mCRPC patients underwent whole-exome sequencing (n = 82) and RNA sequencing (n = 75) of metastatic biopsies before initiating AA/P with the objective of identifying genomic alterations associated with resistance to AA/P. Primary resistance was determined at 12 weeks of treatment using criteria for progression that included serum prostate-specific antigen measurement, bone and computerized tomography imaging and symptom assessments. Acquired resistance was determined using the end point of time to treatment change (TTTC), defined as time from enrollment until change in treatment from progressive disease. Associations of genomic and transcriptomic alterations with primary resistance were determined using logistic regression, Fisher's exact test, single and multivariate analyses. Cox regression models were utilized for determining association of genomic and transcriptomic alterations with TTTC.

Results

At 12 weeks, 32 patients in the cohort had progressed (nonresponders). Median study follow-up was 32.1 months by which time 58 patients had switched treatments due to progression. Median TTTC was 10.1 months (interquartile range: 4.4-24.1). Genes in the Wnt/β-catenin pathway were more frequently mutated and negative regulators of Wnt/β-catenin signaling were more frequently deleted or displayed reduced mRNA expression in nonresponders. Additionally, mRNA expression of cell cycle regulatory genes was increased in nonresponders. In multivariate models, increased cell cycle proliferation scores (≥ 50) were associated with shorter TTTC (hazard ratio = 2.11, 95% confidence interval: 1.17-3.80; P = 0.01).

Conclusions

Wnt/β-catenin pathway activation and increased cell cycle progression scores can serve as molecular markers for predicting resistance to AA/P therapy.

Value-driven attentional capture is modulated by the contents of working memory: An EEG study

Attention and working memory (WM) have previously been shown to interact closely when sensory information is being maintained. However, when non-sensory information is maintained in WM, the relationship between WM and sensory attention may be less strong. In the current study, we used electroencephalography to evaluate whether value-driven attentional capture (i.e., allocation of attention to a task-irrelevant feature previously associated with a reward) and its effects on either sensory or non-sensory WM performance might be greater than the effects of salient, non-reward-associated stimuli. In a training phase, 19 participants learned to associate a color with reward. Then, participants were presented with squares and encoded their locations into WM. Participants were instructed to convert the spatial locations either to another type of sensory representation or to an abstract, relational type of representation. During the WM delay period, task-irrelevant distractors, either previously-rewarded or non-rewarded, were presented, with a novel color distractor in the other hemifield. The results revealed lower alpha power and larger N2pc amplitude over posterior electrode sides contralateral to the previously rewarded color, compared to ipsilateral. These effects were mainly found during relational WM, compared to sensory WM, and only for the previously rewarded distractor color, compared to a previous non-rewarded target color or novel color. These effects were associated with modulations of WM performance. These results appear to reflect less capture of attention during maintenance of specific location information, and suggest that value-driven attentional capture can be mitigated as a function of the type of information maintained in WM.

AbobotulinumtoxinA Efficacy and Safety in Children With Equinus Foot Previously Treated With Botulinum Toxin

BACKGROUND

The effects of botulinum toxin are transient, and repeat injections are required in children with lower-limb spasticity. However, the efficacy of botulinum toxin in patients who have received previous injections has remained largely unexplored.

METHODS

We present subgroup analyses of a phase III study conducted in ambulatory children (aged two to 17) with spastic equinus foot. Patients were randomized to single doses of abobotulinumtoxinA 10 U/kg/leg, 15 U/kg/leg, or placebo injected into the gastrocnemius-soleus complex (one or both legs). The first analysis was prespecified to review the effect of abobotulinumtoxinA in children previously treated with botulinum toxin versus those children new to the treatment; a second post hoc analysis evaluated the effect of abobotulinumtoxinA in children who changed botulinum toxin formulation.

RESULTS

Of the 241 randomized patients, 113 had previously received botulinum toxin, including 86 who had been treated with another formulation. In both analyses, muscle tone (Modified Ashworth Scale) and the Physicians Global Assessment, at week 4, improved with abobotulinumtoxinA treatment versus placebo, regardless of baseline botulinum toxin status. Placebo responses in patients new to treatment were consistently higher than in the previously treated group.

CONCLUSIONS

These results demonstrate similar abobotulinumtoxinA efficacy and safety profiles in children with spasticity who are new to botulinum toxin treatment and those children who were previously treated. The efficacy and safety of abobotulinumtoxinA treatment in these previously treated patients were comparable with the overall trial population, indicating that doses of 10 and 15 U/kg/leg are suitable starting doses for children with spasticity regardless of the previous botulinum toxin preparation used.

A Rare Fourth Branch of the Marginal Mandibular Nerve

This report describes a good example of the rare fourth branch of the marginal mandibular nerve. This case emphasizes the need for respecting the variation in the marginal mandibular nerve when carrying out surgery.

Spasticity Video Challenge: A Look at Methods for Addressing Difficult Cases

As seen in this CME online activity (available at http://courses.elseviercme.com/spasticity/662e), treatment of patients with spasticity due to upper motor neuron syndromes, including traumatic brain injury, stroke, and cerebral palsy, is multifaceted, involving chemodenervation, systemic medications, surgical therapy, rehabilitation efforts, and home care. Optimal care begins with the recognition that each patient's impairments are unique and must be assessed carefully to determine the impact of muscle overactivity, loss of dexterity, and weakness on passive and active function in the context of the patients' goals. While botulinum toxin plays a major role in providing symptomatic relief and functional improvement from hypertonia, it should rarely be used as a standalone treatment.

An electromyographic protocol that distinguishes spasticity from dystonia

PURPOSE

The purpose of this proof of concept study is to demonstrate that electromyographic (EMG) activation patterns of leg muscles differ predictably among patients with predominantly spasticity, patients with predominantly dystonia, and typically developing control subjects during rest, volitional movement, and passively induced movement.

METHODS

Eight control subjects, 6 subjects with dystonia, and 7 subjects with spasticity were recruited, ages 6-25 years. Surface EMG sensors were applied over 4 muscle groups of each leg. EMG recordings and video were obtained during rest, quick stretch, and volitional movement. The number of muscles active during 3 resting, 4 quick stretch, and 8 volitional movement items were averaged and compared across subject groups.

RESULTS

Control subjects showed minimal numbers of muscles active during resting, quick stretch, or volitional movement activities. Spastic subjects showed multiple muscles responding with high amplitude to quick stretch but not to volitional movement activities. Dystonic subjects showed multiple muscles responding to volitional movement activities but not to quick stretch. Analysis with a Kruskal-Wallis test indicated significant differences between the three groups in numbers of muscles activated during quick stretch activities (p= 0.017) and volitional movement activities (p= 0.005).

CONCLUSION

EMG data collected with this protocol may be useful for distinguishing spastic from dystonic hypertonia.

Integrin α4-positive human trophoblast progenitors: functional characterization and transcriptional regulation

STUDY QUESTION

What are the functional characteristics and transcriptional regulators of human trophoblast progenitor cells (TBPCs)?

SUMMARY ANSWER

TBPC lines established from the human smooth chorion by cell sorting for integrin α4 expressed markers of stemness and trophoblast (TB) stage-specific antigens, invaded Matrigel substrates and contributed to the cytotrophoblasts (CTBs) layer of smooth chorion explants with high-mobility group protein HMGI-C (HMGA2) and transcription factor GATA-4 (GATA4) controlling their progenitor state and TB identity.

WHAT IS KNOWN ALREADY

Previously, we reported the derivation of TBPC lines by trypsinization of colonies that formed in cultures of chorionic mesenchyme cells that were treated with an activin nodal inhibitor. Microarray analyses showed that, among integrins, α4 was most highly expressed, and identified HMGA2 and GATA4 as potential transcriptional regulators.

STUDY DESIGN, SIZE, DURATION

The aim of this study was to streamline TBPC derivation across gestation. High-cell surface expression of integrin α4 enabled the use of a fluorescence-activated cell sorter (FACS) approach for TBPC isolation from the human smooth chorion (n = 6 lines). To confirm their TBPC identity, we profiled their expression of stemness and TB markers, and growth factor receptors. At a functional level, we assayed their invasive capacity (n = 3) and tropism for the CTB layer of the smooth chorion (n = 3). At a molecular level, we studied the roles of HMGA2 and GATA4.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Cells were enzymatically disassociated from the human smooth chorion across gestation. FACS was used to isolate the integrin α4-positive population. In total, we established six TBPC lines, two per trimester. Their identity was determined by immunolocalization of a suite of antigens. Function was assessed via Matrigel invasion and co-culture with explants of the human smooth chorion. An siRNA approach was used to down-regulate HMGA2 and GATA4 expression and the results were confirmed by immunoblotting and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. The endpoints analyzed included proliferation, as determined by 5-bromo-2'-deoxyuridine (BrDU) incorporation, and the expression of stage-specific antigens and hormones, as determined by qRT-PCR and immunostaining approaches.

MAIN RESULTS AND THE ROLE OF CHANCE

As with the original cell lines, the progenitors expressed a combination of human embryonic stem cell and TB markers. Upon differentiation, they primarily formed CTBs, which were capable of Matrigel invasion. Co-culture of the cells with smooth chorion explants enabled their migration through the mesenchyme after which they intercalated within the chorionic CTB layer. Down-regulation of HMGA2 showed that this DNA-binding protein governed their self-renewal. Both HMGA2 and GATA4 had pleitropic effects on the cells' progenitor state and TB identity.

LIMITATIONS, REASONS FOR CAUTION

This study supported our hypothesis that TBPCs from the chorionic mesenchyme can contribute to the subpopulation of CTBs that reside in the smooth chorion. In the absence of in vivo data, which is difficult to obtain in humans, the results have the limitations common to all in vitro studies.

WIDER IMPLICATIONS OF THE FINDINGS

The accepted view is that progenitors reside among the villous CTB subpopulation. Here, we show that TBPCs also reside in the mesenchymal layer of the smooth chorion throughout gestation. We theorize that they can contribute to the CTB layer in this region. This phenomenon may be particularly important in pathological situations when CTBs of the smooth chorion might provide a functional reserve for CTBs of the placenta proper.

STUDY FUNDING/COMPETING INTERESTS

Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health under award P50HD055764. O.G., N.L., K.O., A.P., T.G.-G., M.K., A.B., M.G. have nothing to disclose. S.J.F. received licensing fees and royalties from SeraCare Life Sciences for trisomic TBPC lines that were derived according to the methods described in this manuscript.

TRIAL REGISTRATION NUMBER

N/A.

AbobotulinumtoxinA for Equinus Foot Deformity in Cerebral Palsy: A Randomized Controlled Trial

BACKGROUND

Although botulinum toxin is a well-established treatment of focal spasticity in cerebral palsy, most trials have been small, and few have simultaneously assessed measures of muscle tone and clinical benefit.

METHODS

Global, randomized, controlled study to assess the efficacy and safety of abobotulinumtoxinA versus placebo in cerebral palsy children with dynamic equinus foot deformity. Patients were randomized (1:1:1) to abobotulinumtoxinA 10 U/kg/leg, 15 U/kg/leg, or placebo injections into the gastrocnemius-soleus complex (1 or both legs injected). In the primary hierarchical analysis, demonstration of benefit for each dose required superiority to placebo on the primary (change in Modified Ashworth Scale from baseline to week 4) and first key secondary (Physician's Global Assessment at week 4) end points.

RESULTS

Two hundred and forty-one patients were randomized, and 226 completed the study; the intention to treat population included 235 patients (98%). At week 4, Modified Ashworth Scale scores significantly improved with abobotulinumtoxinA; mean (95% confidence interval) treatment differences versus placebo were -0.49 (-0.75 to -0.23; P = .0002) for 15 U/kg/leg and -0.38 (-0.64 to -0.13; P = .003) for 10 U/kg/leg. The Physician's Global Assessment treatment differences versus placebo of 0.77 (0.45 to 1.10) for 15 U/kg/leg and 0.82 (0.50 to 1.14) for 10 U/kg/leg were also significant (both Ps < .0001). The most common treatment-related adverse event was muscular weakness (10 U/Kg/leg = 2; placebo = 1).

CONCLUSIONS

AbobotulinumtoxinA improves muscle tone in children with dynamic equinus resulting in an improved overall clinical impression and is well tolerated.

Abstract P4-07-05: Cyclin D1 induction of dicer governs microRNA processing and expression in breast cancer

MicroRNAs (miRNAs), a class of non-coding small RNA, regulate gene expression through base-pairing binding to the complementary sequence in the 3’ untranslated region (3’ UTR) of mRNA. miRNAs contribute to the timing of development, apoptosis, cell cycle progression, cellular proliferation, stem cell self-renewal, cancer initiation and metastasis. The expression of miRNA is regulated during cell-cycle transition and cellular contact in part via active degradation. Aberrant expression of miRNAs or mutations of miRNA genes have been described in many types of tumors, including mammary tumors. The RNase III endoribonuclease Dicer cleaves long double-stranded RNA (dsRNA) or stem-loop-stem structured pre-miRNA to form mature miRNAs. RNAi-mediated knock-down of Dicer in human cells led to defects in both miRNA production and shRNA-mediated RNAi.

Initially cloned as a breakpoint rearrangement in parathyroid adenoma, the cyclin D1 gene encodes the regulatory subunit of the holoenzyme that phosphorylates and inactivates both the pRb tumor suppressor and the key inducer of mitochondrial biogenesis NRF-1. In addition, a DNA bound form of cyclin D1 regulates gene expression. Cyclin D1 expression is induced during mammary gland and retinal differentiation, and deletion of the murine cyclin D1 gene resulted in failed terminal alveolar breast bud development and retinal degeneration. Diverse biological functions regulated by cyclin D1 include the induction of cellular proliferation, angiogenesis, cellular migration, DNA damage repair, mitochondrial biogenesis, stem cell maintenance, and miRNA expression. Cyclin D1 was shown to regulate the miR-17/20 locus and found to bind the miR-17/20 regulatory region.

In order to determine further the mechanism by which cyclin D1 regulates non-coding RNA, we conducted studies of miRNA processing. We established cyclin D1-/- mouse embryonic fibroblasts cells (MEFs) and cyclin D1 knockdown (KD) MCF-7 human breast cancer cells. miRNA analysis indicated an induction of mature miRNA expression in cyclin D1 overexpressing cells. Analysis of the miRNA processing regulators demonstrated the selective induction of Dicer expression by cyclin D1. In cyclin D1-/- cells the reduction of Dicer abundance was accompanied by impairment of pre-miRNA to mature miRNA processing, which was restored with cyclin D1 rescue. Transient transgenic expression of cyclin D1 in the mouse mammary gland, or sustained transgenic expression of cyclin D1 induced mouse mammary gland tumors, recapitulated the induction of Dicer expression. Cyclin D1 and Dicer expression were correlated in luminal A and basal-like human breast cancer. Cyclin D1 regulation of cellular proliferation and migration was dependent upon Dicer. By demonstrating cyclin D1 induced Dicer abundance and function in tissue culture and in vivo, we provide evidence for novel crosstalk between the cell-cycle and non-coding miRNA biogenesis.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-07-05.

Abstract P2-06-02: Pparg deacetylation by SIRT1 determines breast tumor lipid synthesis and growth

Peroxisome proliferator-activated receptorg (Pparγ) is a member of the nuclear receptor (NR) superfamily, which regulates diverse biological functions including lipogenesis and differentiation, anti-inflammation, insulin sensitivity, cellular proliferation, and autophagy. Independent lines of evidence support a role for Pparγ as either a collaborative oncogene or as a tumor suppressor. Heterozygous mutations of Pparγ have been detected in 4/55 patients with colon cancer and a chromosomal translocation between PAX8 and Pparγ in follicular thyroid cancer appeared to serve as a dominant inhibitor of endogenous Pparγ expression. Pparγ agonists reduced tumorigenesis in several in vivo models. In contrast, several studies suggest Pparγ may enhance tumor growth. Pparγ ligands increased polyp numbers in the Apc mouse model of familial adenomatosis. Pparγ and its ligands inhibit breast tumor growth; however, constitutively active Pparγ collaborated in mammary oncogenesis with polyoma middle T antigen or oncogenic ErbB2.

Pparγ activation involves post-translational modifications including phosphorylation and sumoylation upon growth factor or ligand stimulus. Mutation of the Pparγ1 sumoylation site at K77 and K365 demonstrated that K77 may either reduce Pparγ-dependent gene induction and enhance repression or reduce repression, depending upon the synthetic reporter gene used. Lysine residues of nuclear receptors also serve as substrates for acetylation and Pparγ binds co-activators and co-repressors with intrinsic or associated histone acetylase or deacetylase activity including NCoR, SMRT, SIRT1, and p300. Initially characterized for the ERα, AR and, subsequently, the orphan nuclear receptor steroidogenic factor 1 (SF-1), acetylation occurs at a conserved lysine motif shared amongst evolutionarily related nuclear receptors. Several nuclear receptors and co-integrators involved in lipid metabolism are regulated by acetylation including p300, PGC1α, FXR, LXR and RAR. Both TSA- and NAD-sensitive HDACs (e.g. SIRT1) regulate Pparγ function and SIRT1 inhibits Pparγ-dependent adipocyte differentiation. Whether Pparγ is acetylated in cancer cells and how Pparγ exerts it's crucial, though controversial, function in tumorigenesis have not been established.

Pparγ induces gene transcription through binding specific NR half-sites and through non-canonical binding sequences (such as CREB/AP-1 sites). Transcriptional repression involves Pparγ sumoylation at lysine 77 (K77). Herein, Pparγ was shown to be acetylated at nine distinct lysine residues. SIRT1 bound and deacetylated Pparγ at K154/155. ChIP-Seq analysis for genome-wide DNA binding demonstrated the acetylation site was required for binding NR half-sites, but was not required for non-canonical site binding. Breast tumor growth, de novo lipid synthesis, induction of autophagy and evasion of apoptosis was promoted by K154/155 and inhibited by K77 in vivo. Pparγ acetylation induced a gene signature that was increased in breast cancer, associated with a reduction in SIRT1 abundance and poor outcome. The Pparγ acetylation site determines binding to autophagy and apoptosis signaling to regulate breast tumor lipid metabolism and growth.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-06-02.

Abstract P5-11-04: Post-translational modification of the cell-fate factor Dachshund determines p53 binding and signaling modules in breast cancer

Breast cancer is a leading form of cancer in the world. Initially cloned as a dominant inhibitor of the hyperactive EGFR, Ellipse, in Drosophila, the mammalian DACH1 regulates expression of target genes in part through interacting with DNA-binding transcription factors (c-Jun, Smads, Six, ERα), and in part through intrinsic DNA-sequence specific binding to Forkhead binding sites. The Drosophila dac gene is a key member of the retinal determination gene network (RDGN), which also includes eyes absent (eya), ey, twin of eyeless (toy), teashirt (tsh) and sin oculis (so), that specifies eye tissue identity.

Several lines of evidence suggest DACH1 may function as a tumor suppressor. Clinical studies have demonstrated a correlation between poor prognosis and reduced expression of the cell-fate determination factor DACH1 in breast cancer, and loss of DACH1 expression has been observed in prostate and endometrial cancer. DACH1 inhibits breast cancer tumor metastasis and reduces breast cancer stem cell expansion via Sox2/Nanog. Although these studies suggest DACH1 may function as a tumor suppressor, the molecular mechanisms remain poorly defined. Herein, endogenous DACH1 co-localized with p53 in a nuclear, extranucleolar compartment and bound to p53 in human breast cancer cell lines, p53 and DACH1 bound common genes in ChIP-Seq. Full inhibition of breast cancer contact-independent growth by DACH1 required p53. The p53 breast cancer mutants R248Q and R273H, evaded DACH1 binding. DACH1 phosphorylation at serine residue (S439) inhibited p53 binding and phosphorylation at p53 amino-terminal sites (S15, S20) enhanced DACH1 binding. DACH1 binding to p53 was inhibited by NAD-dependent deacetylation via DACH1 K628. DACH1 repressed p21CIP1 and induced RAD51, an association found in basal breast cancer. DACH1 inhibits breast cancer cellular growth in an NAD and p53 dependent manner through direct protein-protein association.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-11-04.