Single-cell analysis reveals context-dependent, cell-level selection of mtDNA.

Heteroplasmy occurs when wild-type and mutant mitochondrial DNA (mtDNA) molecules co-exist in single cells1. Heteroplasmy levels change dynamically in development, disease and ageing2,3, but it is unclear whether these shifts are caused by selection or drift, and whether they occur at the level of cells or intracellularly. Here we investigate heteroplasmy dynamics in dividing cells by combining precise mtDNA base editing (DdCBE)4 with a new method, SCI-LITE (single-cell combinatorial indexing leveraged to interrogate targeted expression), which tracks single-cell heteroplasmy with ultra-high throughput. We engineered cells to have synonymous or nonsynonymous complex I mtDNA mutations and found that cell populations in standard culture conditions purge nonsynonymous mtDNA variants, whereas synonymous variants are maintained. This suggests that selection dominates over simple drift in shaping population heteroplasmy. We simultaneously tracked single-cell mtDNA heteroplasmy and ancestry, and found that, although the population heteroplasmy shifts, the heteroplasmy of individual cell lineages remains stable, arguing that selection acts at the level of cell fitness in dividing cells. Using these insights, we show that we can force cells to accumulate high levels of truncating complex I mtDNA heteroplasmy by placing them in environments where loss of biochemical complex I activity has been reported to benefit cell fitness. We conclude that in dividing cells, a given nonsynonymous mtDNA heteroplasmy can be harmful, neutral or even beneficial to cell fitness, but that the 'sign' of the effect is wholly dependent on the environment.

Implementation of a New Surgeon Onboarding Program in an Academic-affiliated Community Hospital.

Best practices in onboarding are well-established, but surgeons frequently receive suboptimal introductions to new practice settings. At the same time, increasing regionalization of surgical programs and strategic alignments between academic and community hospitals have increased the demand for surgeons to practice at multiple sites with variable resources and institutional cultures. In response to this growing problem, we developed and implemented a surgeon onboarding program in an academic-affiliated community hospital. This pilot demonstrated excellent process adherence, user satisfaction, and significant improvements in preparedness to practice. We therefore conclude that robust onboarding is feasible and can be readily implemented by a local team to promote safe transitions in practice settings for surgeons.

Impact of a Virtual Professional Development Coaching Program on the Professional Fulfillment and Well-Being of Women Surgery Residents: A Randomized Controlled Trial.

OBJECTIVE: Evaluate the effect of a virtual coaching program offered to women surgery residents in a surgical society. BACKGROUND: Randomized controlled experiments evaluating the effect of coaching on trainee well-being and burnout is lacking. METHODS: Women surgery residents in the Association of Women Surgeons were recruited to participate in a randomized controlled trial of the effects of a virtual coaching program on trainee well-being. Attending surgeons served as coaches after completing in-person training. Residents (n=237) were randomized to intervention (three 1:1 coaching sessions over 9 mo) or control (e-mailed wellness resources). Participants were surveyed at baseline and postintervention using validated measures of well-being, burnout, and resilience. Changes in outcome measures between presurvey and postsurvey were compared between study arms. RESULTS: Survey response rates were 56.9% (n=66) in the control group and 69.4% (n=84) in the intervention group ( P =0.05). The intervention group showed significant improvement in professional fulfillment ( P =0.021), burnout (0.026), work exhaustion (0.017), self-valuation (0.003), and well-being ( P =0.002); whereas the control group showed significant improvement in self-valuation ( P =0.015) and significant decline in resilience ( P =0.025). The intervention group had a significant improvement in well-being ( P =0.015) and intolerance of uncertainty ( P =0.015) compared to controls. CONCLUSIONS: Women surgery residents who participated in a remote coaching program offered by a surgical society demonstrated improvement in aspects of well-being relative to peers who did not receive coaching. Therefore, remote coaching offered by a professional society may be a useful component of initiatives directed at trainee well-being.

Do Resident Coaching Programs Benefit their Coaches? Impact of a Professional Development Coaching Program on The Coaches.

BACKGROUND: Coaching has been shown to decrease physician burnout; however, coachee outcomes have been the focus. We report the impact of coaching on women-identifying surgeons who participated as coaches in a 9-month virtual program. METHODS: A coaching program was implemented in the Association of Women Surgeons (AWS) to determine the effects of coaching on well-being and burnout from 2018 to 2020. AWS members volunteered and completed training in professional development coaching. Pre- and post-study measures were assessed, and bivariate analysis performed based on burnout and professional fulfillment score. RESULTS: Seventy-five coaches participated; 57 completed both pre- and post-study surveys. There were no significant changes in burnout or professional fulfillment including the Positive Emotion, Engagement, Relationship, Meaning, and Accomplishment scale, hardiness, self-valuation, coping, gratitude, or intolerance of uncertainty scores from baseline to post-survey. On bivariate analysis, hardiness was associated with lower burnout throughout the duration of the program. Coaches with lower burnout at the end of the program met with their coachee more frequently than coaches with higher burnout [mean (SD) 3.95(2.16) versus 2.35(2.13) p = 0.0099]. DISCUSSION: Burnout and professional fulfillment demonstrated no change in women surgeons who participated as professional development coaches. Those with lower burnout and higher professional fulfillment at the end of the program were found to have higher hardiness, which may be worth future investigation. CONCLUSIONS: Acquisition of coaching skills did not directly improve well-being in faculty who participated in a resident coaching program. Future studies would benefit from control groups and exploration of qualitative benefits of coaching.

Radiation Cleaved Drug-Conjugate Linkers Enable Local Payload Release.

Conjugation of therapeutic payloads to biologics including antibodies and albumin can enhance the selectively of drug delivery to solid tumors. However, achieving activity in tumors while avoiding healthy tissues remains a challenge, and payload activity in off-target tissues can cause toxicity for many such drug-conjugates. Here, we address this issue by presenting a drug-conjugate linker strategy that releases an active therapeutic payload upon exposure to ionizing radiation. Localized X-ray irradiation at clinically relevant doses (8 Gy) yields 50% drug (doxorubicin or monomethyl auristatin E, MMAE) release under hypoxic conditions that are traditionally associated with radiotherapy resistance. As proof-of-principle, we apply the approach to antibody- and albumin-drug conjugates and achieve >2000-fold enhanced MMAE cytotoxicity upon irradiation. Overall, this work establishes ionizing radiation as a strategy for spatially localized cancer drug delivery.

Survival After Adrenalectomy for Metastatic Lung Cancer.

BACKGROUND: Adrenal metastasectomy is associated with increased survival in non-small cell lung cancer (NSCLC) with isolated adrenal metastases. Although clinical use of adrenal metastasectomy has expanded, indications remain poorly defined. The aim of this study was to evaluate the clinical benefit of adrenal metastasectomy for all lung cancer subtypes. PATIENTS AND METHODS: We performed a retrospective cohort study of patients who underwent adrenal metastasectomy for metastatic lung cancer at six institutions between 2001 and 2015. The primary outcomes were disease-free survival (DFS) and overall survival (OS). Cox proportional hazards regressions and Kaplan-Meier survival analysis were performed. RESULTS: For 122 patients, the mean age was 60.5 years and 49.2% were female. Median time to detection of the metastasis was 11 months, and 41.8% were ipsilateral to the primary lung cancer. Median DFS was 40 months (1 year: 64.8%; 5 year: 42.9%). Factors associated with longer DFS included primary tumor resection [hazard ratio (HR): 0.001; p = 0.005], longer time to adrenal metastasis (HR: 0.94; p = 0.005), and ipsilateral metastases (HR: 0.13; p = 0.004). Shorter DFS corresponded with older age (HR: 1.11; p = 0.01), R1 resection (HR: 8.94; p = 0.01), adjuvant radiation (HR: 9.45; p = 0.02), and open adrenal metastasectomy (HR: 10.0; p = 0.03). Median OS was 47 months (1 year: 80.2%; 5 year: 35.2%). Longer OS was associated with ipsilateral metastasis (HR: 0.55; p = 0.02) and adjuvant chemotherapy (HR: 0.35; p = 0.02). Shorter OS was associated with extra-adrenal metastases at adrenalectomy (HR: 3.52; p = 0.007), small cell histology (HR: 15.0; p = 0.04), and lung radiation (HR: 3.37; p = 0.002). DISCUSSION: Durable survival was observed in patients undergoing adrenal metastasectomy and should be considered for isolated adrenal metastases of NSCLC. Small cell histology and extra-adrenal metastases are relative contraindications to adrenal metastasectomy.

Barriers to Pursuing a Career in Surgery: An Institutional Survey of Harvard Medical School Students.

OBJECTIVE: This study aimed to elucidate current medical student perceptions on barriers to a career in surgery, with a particular focus on gender-specific differences. SUMMARY BACKGROUND DATA: Although gender parity in medical school composition has been reached, women continue to be underrepresented in the field of surgery. METHODS: An anonymous, single-institution, internet-based survey conducted at Harvard Medical School. RESULTS: Approximately 720 medical students were surveyed and 261 completed the questionnaire (36.3%; 58.6% women, 41% men, 0.4% transgender). Overall, there was no significant gender difference in intention to pursue surgery (27% of men, 22% of women; P = 0.38). Sixty-nine percent of all students and 75% of those pursuing surgery reported verbal discouragement from pursuing a surgical career. Women were significantly more likely to perceive that the verbal discouragement was based on gender (P < 0.0001), age (P < 0.0001), and family aspirations (P = 0.043) compared to men. Surgical work hours and time for outside interests were the greatest deterrents for both genders. Significantly more women reported concerns about time to date or marry (P = 0.042), time to spend with family (P = 0.015), finding time during residency to have a child (P < 0.0001), taking maternity/paternity leave during residency (P < 0.0001), and being too old after residency to have a child (P < 0.0001). CONCLUSIONS: Both men and women reported high rates of verbal discouragement, but more women perceived that the discouragement was gender-based. Concerns about marriage and childbearing/rearing significantly deterred more women than men. Family aspirations were also a significant factor for men to choose an alternative career path. Additional support within the surgical field is needed to mitigate these concerns and support trainees in both their career and familial aspirations.

Adrenalectomy for Secondary Malignancy: Patients, Outcomes, and Indications.

OBJECTIVE: The goal of this study was to examine a multi-institutional experience with adrenal metastases to describe survival outcomes and identify subpopulations who benefit from adrenal metastasectomy. BACKGROUND: Adrenalectomy for metastatic disease is well-described, although indications and outcomes are incompletely defined. METHODS: A retrospective cohort study was performed of patients undergoing adrenalectomy for secondary malignancy (2002-2015) at 6 institutions. The primary outcomes were disease free survival (DFS) and overall survival (OS). Analysis methods included Kaplan-Meier and Cox proportional hazards. RESULTS: Of 269 patients, mean age was 60.1 years; 50% were male. The most common primary malignancies were lung (n = 125, 47%), renal cell (n = 38, 14%), melanoma (n = 33, 12%), sarcoma (n = 18, 7%), and colorectal (n = 12, 5%). The median time to detection of adrenal metastasis after initial diagnosis of the primary tumor was 17 months (interquartile range: 6-41). Post-adrenalectomy, the median DFS was 18 months (1-year DFS: 54%, 5-year DFS: 31%). On multivariable analysis, lung primary was associated with longer DFS [hazard ratio (HR): 0.49, P = 0.008). Extra-adrenal oligometastatic disease at initial presentation (HR: 1.84, P = 0.016), larger tumor size (HR: 1.07, P = 0.013), chemotherapy as treatment of the primary tumor (HR: 2.07 P = 0.027) and adjuvant chemotherapy (HR: 1.95, P = 0.009) were associated with shorter DFS. Median OS was 53 months (1-year OS: 83%, 5-year OS: 43%). On multivariable analysis, extra-adrenal oligometastatic disease at adrenalectomy (HR: 1.74, P = 0.031), and incomplete resection of adrenal metastasis (R1 margins; HR: 1.62, P = 0.034; R2 margins; HR: 5.45, P = 0.002) were associated with shorter OS. CONCLUSIONS: Durable survival is observed in patients undergoing adrenal metastasectomy and should be considered for subjects with isolated adrenal metastases.

Detecting Immune Response to Therapies Targeting PDL1 and BRAF by Using Ferumoxytol MRI and Macrin in Anaplastic Thyroid Cancer.

Background Anaplastic thyroid cancer (ATC) is aggressive with a poor prognosis, partly because of the immunosuppressive microenvironment created by tumor-associated macrophages (TAMs). Purpose To understand the relationship between TAM infiltration, tumor vascularization, and corresponding drug delivery by using ferumoxytol-enhanced MRI and macrin in an ATC mouse model. Materials and Methods ATC tumors were generated in 6-8-week-old female B6129SF1/J mice through intrathyroid injection to model orthotopic tumors, or intravenously to model hematogenous metastasis, and prospectively enrolled randomly into treatment cohorts (n = 94 total; August 1, 2018, to January 15, 2020). Mice were treated with vehicle or combined serine/threonine-protein kinase B-Raf (BRAF) kinase inhibitor (BRAFi) and anti-PDL1 antibody (aPDL1). A subset was cotreated with therapies, including an approximately 70-nm model drug delivery nanoparticle (DDNP) to target TAM, and an antibody-neutralizing colony stimulating factor 1 receptor (CSF1R). Imaging was performed at the macroscopic level with ferumoxytol-MRI and microscopically with macrin. Genetically engineered BrafV600E/WT p53-null allografts were used and complemented by a GFP-transgenic derivative and human xenografts. Tumor-bearing organs were processed by using tissue clearing and imaged with confocal microscopy and MRI. Two-tailed Wilcoxon tests were used for comparison (≥five per group). Results TAM levels were higher in orthotopic thyroid tumors compared with pulmonary metastatic lesions by 79% ± 23 (standard deviation; P < .001). These findings were concordant with ferumoxytol MRI, which showed 136% ± 88 higher uptake in thyroid lesions (P = .02) compared with lung lesions. BRAFi and aPDL1 combination therapy resulted in higher tumor DDNP delivery by 39% ± 14 in pulmonary lesions (P = .004). Compared with the untreated group, tumors following BRAFi, aPDL1, and CSF1R-blocking antibody combination therapy did not show greater levels of TAM or DDNP (P = .82). Conclusion In a mouse model of anaplastic thyroid cancer, ferumoxytol MRI showed 136% ± 88 greater uptake in orthotopic thyroid tumors compared with pulmonary lesions, which reflected high vascularization and greater tumor-associated macrophage (TAM) levels. Serine/threonine-protein kinase B-Raf inhibitor and anti-programmed death ligand 1 antibody elicited higher local TAM levels and 43% ± 20 greater therapeutic nanoparticle delivery but not higher vascularization in pulmonary tumors. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Luker in this issue.

American Association of Clinical Endocrinology And Associazione Medici Endocrinologi Thyroid Nodule Algorithmic Tool.

OBJECTIVE: The first edition of the American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi Guidelines for the Diagnosis and Management of Thyroid Nodules was published in 2006 and updated in 2010 and 2016. The American Association of Clinical Endocrinology/American College of Endocrinology/Associazione Medici Endocrinologi multidisciplinary thyroid nodules task force was charged with developing a novel interactive electronic algorithmic tool to evaluate thyroid nodules. METHODS: The Thyroid Nodule App (termed TNAPP) was based on the updated 2016 clinical practice guideline recommendations while incorporating recent scientific evidence and avoiding unnecessary diagnostic procedures and surgical overtreatment. This manuscript describes the algorithmic tool development, its data requirements, and its basis for decision making. It provides links to the web-based algorithmic tool and a tutorial. RESULTS: TNAPP and TI-RADS were cross-checked on 95 thyroid nodules with histology-proven diagnoses. CONCLUSION: TNAPP is a novel interactive web-based tool that uses clinical, imaging, cytologic, and molecular marker data to guide clinical decision making to evaluate and manage thyroid nodules. It may be used as a heuristic tool for evaluating and managing patients with thyroid nodules. It can be adapted to create registries for solo practices, large multispecialty delivery systems, regional and national databases, and research consortiums. Prospective studies are underway to validate TNAPP to determine how it compares with other ultrasound-based classification systems and whether it can improve the care of patients with clinically significant thyroid nodules while reducing the substantial burden incurred by those who do not benefit from further evaluation and treatment.

BRAFV600E Mutation is Associated with an Increased Risk of Papillary Thyroid Cancer Recurrence.

BACKGROUND: Papillary thyroid carcinoma is the most common endocrine malignancy and one of the most common cancers worldwide. However, the optimal timing and frequency of surveillance to assess for recurrence remain undetermined. As the incidence of thyroid cancer continues to rise worldwide, identifying risk factors for recurrence and investigating intervals and durations of surveillance are paramount to adapt treatment and follow-up plans to high-risk individuals and to reduce interventions for low-risk patients. METHODS: Our dataset included an unselected cohort of papillary thyroid carcinoma (PTC) patients who underwent a total thyroidectomy (or unilateral then completion thyroidectomy) at a single institution from 2000 to 2007. BRAF genotyping was performed on available specimens by a validated PCR-based assay. Pathologic structural recurrence was the primary outcome. We performed univariate and multivariable analyses to identify predictors of cancer recurrence. RESULTS: In total, 599 patients underwent complete resection of the thyroid gland for PTC. The cohort was young (mean age 45.0 years), predominately female (n = 462, 76.9%), and median follow-up was 10.3 years (IQR 5.4-12.2). Recurrence occurred more commonly in the BRAFV600E group (18.6 vs. 9.9%, p = 0.02). BRAF independently predicted PTC recurrence (HR 2.81, p = 0.006). CONCLUSIONS: BRAF mutation is an independent predictor of papillary thyroid carcinoma long-term recurrence. Understanding molecular characteristics of individual thyroid cancers may help risk-stratify patients and direct them toward more appropriate initial care and long-term surveillance strategies.

MANAGEMENT OF HYPERPARATHYROIDISM IN KIDNEY TRANSPLANTATION CANDIDATES: A NEED FOR CONSENSUS.

Objective: To assess the evolving standards of care for hyperparathyroidism in kidney transplant candidates. Methods: An 11-question, Institutional Review Board-approved survey was designed and reviewed by multiple institutions. The questionnaire was made available to the American Society of Transplantation's Kidney Pancreas Community of Practice membership via their online hub from April through July 2019. Results: Twenty percent (n = 41) of kidney transplant centers responded out of 202 programs in the United States. Forty-one percent (n = 17) of respondents believed medical literature supports the concept that a serum parathyroid hormone level greater than 800 pg/mL could endanger the survival of a transplanted kidney and therefore makes transplantation in an affected patient relatively or absolutely contraindicated. Sixty-six percent (n = 27) said they occasionally recommend parathyroidectomy for secondary hyperparathyroidism prior to transplantation, and 66% (n = 27) recommend parathyroidectomy after transplantation based on persistent, unsatisfactory posttransplantation parathyroid hormone levels. Forty-six percent (n = 19) prefer subtotal parathyroidectomy as their choice; 44% (n = 18) had no standard preference. Endocrine surgery and otolaryngology were the most common surgical specialties consulted to perform parathyroidectomy in kidney transplant candidates. The majority of respondents (71%, n = 29) do not involve endocrinologists in the management of kidney transplantation candidates. Conclusion: Our survey shows wide divergence of clinical practice in the area of surgical management of kidney transplantation candidates with hyperparathyroidism. We suggest that medical/surgical societies involved in the transplantation care spectrum convene a multidisciplinary group of experts to create a new section in the kidney transplantation guidelines addressing the collaborative management of parathyroid disease in transplantation candidates. Abbreviations: AACE = American Association of Clinical Endocrinologists; AAES = American Association of Endocrine Surgeons; AHNS = American Head and Neck Society; CKD = chronic kidney disease; CKD-MBD = chronic kidney disease-mineral and bone disorder; ESRD = end-stage renal disease; HPT = hyperparathyroidism; KDIGO = Kidney Disease Improving Global Outcomes; KT = kidney transplantation; KTC = kidney transplant candidate; PTH = parathyroid hormone; PTX = parathyroidectomy; US = ultrasonography.

Anti-PD-1/PD-L1 therapy augments lenvatinib's efficacy by favorably altering the immune microenvironment of murine anaplastic thyroid cancer.

Patients with anaplastic thyroid cancer (ATC) have an extremely poor prognosis despite multimodal therapy with surgery and chemoradiation. Lenvatinib, a multi-targeted tyrosine kinase inhibitor, as well as checkpoint inhibitors targeting the programmed cell death pathway, have proven effective in some patients with advanced thyroid cancer. Combination of these therapies is a potential means to boost effectiveness and minimize treatment resistance in ATC. We utilized our novel immunocompetent murine model of orthotopic ATC to demonstrate that lenvatinib led to significant tumor shrinkage and increased survival, while combination therapy led to dramatic improvements in both. Lenvatinib monotherapy increased tumor-infiltrating macrophages, CD8+ T-cells, regulatory T-cells, and most notably, polymorphonuclear myeloid derived suppressor cells (PMN-MDSCs). While both combination therapies led to further increases in CD8+ T-cells, only the lenvatinib and anti-PD-1 combination decreased PMN-MDSCs. PMN-MDSC expansion was also seen in the blood of mice and one patient receiving lenvatinib therapy for ATC. RNA-Seq of the ATC cell line used in our mouse model demonstrated that lenvatinib has multifaceted effects on angiogenesis, response to hypoxia, the epithelial-to-mesenchymal transition, and on multiple pathways implicated in inflammation and host immunity. Combination of lenvatinib with anti-Gr-1 antibody ameliorated lenvatinib's expansion of MDSCs and significantly improved lenvatinib's anti-tumor effect. These data suggest that MDSCs play a negative role in ATC's response to lenvatinib and support future study of their role as a potential biomarker and treatment target.

Leadership in American Surgery: Women are Rising to the Top.

OBJECTIVE: To celebrate the increasing representation of women as leaders in American surgery and provide suggestions for increasing diversity in leadership. BACKGROUND: Women were barred from entering the practice of medicine or surgery until the mid 1800's when Elizabeth Blackwell led the way as the first woman admitted to medical school. Although the numbers of women practicing medicine and surgery have increased exponentially since Dr Blackwell graduated, the number of women in leadership positions has remained low until recently. METHODS: An analysis of the literature on the history of women in surgery and the websites of the major surgical societies. RESULTS: More women are now rising to leadership positions in surgery, both in academics and within surgical organizations. The American College of Surgeons and many other surgical societies, as well as an increasing number of academic departments of surgery have realized that women can be inspiring and capable leaders. However, increasing the number of under-represented minority women in leadership positions remains an opportunity for improvement. CONCLUSIONS: Great progress has been made in the advancement of women into leadership positions in surgery. To continue this trend and increase the number of under-represented minority women in surgery will require attention to recruitment, mentorship, and sponsorship.

A Long, Unnerving Road: Malpractice Claims Involving the Surgical Management of Thyroid and Parathyroid Disease.

BACKGROUND: Given their profound emotional, physical, and financial toll on patients and surgeons, we studied the characteristics, costs, and contributing factors of thyroid and parathyroid surgical malpractice claims. METHODS: Using the Controlled Risk Insurance Company Strategies' Comparative Benchmarking System database, representing ~30% of all US paid and unpaid malpractice claims, 5384 claims filed against general surgeons and otolaryngologists from 1995-2015 were reviewed to isolate claims involving the surgical management of thyroid and parathyroid disease. These claims were studied, and multivariable regression analysis was performed to identify factors associated with plaintiff payout. RESULTS: One hundred twenty-eight thyroid and parathyroid surgical malpractice claims were isolated. The median time from alleged harm event to closure of a malpractice case was 39 months. The most common associated complications were bilateral recurrent laryngeal nerve (RLN) injury (n = 23) and hematoma (n = 18). Complications led to death in 18 cases. Patient payout occurred in 33% of claims (n = 42), and the median cost per claim was $277,913 (IQR $87,343-$783,663). On multivariable analysis, bilateral RLN injury was predictive of patient payout (OR 3.58, p = 0.03), while procedure, death, and surgeon specialty were not. CONCLUSION: Though rare, malpractice claims related to thyroid and parathyroid surgery are costly, time-consuming, and reveal opportunities for early surgeon-patient resolution after poor outcomes.

Theranostic near-infrared fluorescent nanoplatform for imaging and systemic siRNA delivery to metastatic anaplastic thyroid cancer.

Anaplastic thyroid cancer (ATC), one of the most aggressive solid tumors, is characterized by rapid tumor growth and severe metastasis to other organs. Owing to the lack of effective treatment options, ATC has a mortality rate of ∼100% and median survival of less than 5 months. RNAi nanotechnology represents a promising strategy for cancer therapy through nanoparticle (NP) -mediated delivery of RNAi agents (e.g., siRNA) to solid tumors for specific silencing of target genes driving growth and/or metastasis. Nevertheless, the clinical success of RNAi cancer nanotherapies remains elusive in large part because of the suboptimal systemic siRNA NP delivery to tumors and the fact that tumor heterogeneity produces variable NP accumulation and thus, therapeutic response. To address these challenges, we here present an innovative theranostic NP platform composed of a near-infrared (NIR) fluorescent polymer for effective in vivo siRNA delivery to ATC tumors and simultaneous tracking of the tumor accumulation by noninvasive NIR imaging. The NIR polymeric NPs are small (∼50 nm), show long blood circulation and high tumor accumulation, and facilitate tumor imaging. Systemic siRNA delivery using these NPs efficiently silences the expression of V-Raf murine sarcoma viral oncogene homolog B (BRAF) in tumor tissues and significantly suppresses tumor growth and metastasis in an orthotopic mouse model of ATC. These results suggest that this theranostic NP system could become an effective tool for NIR imaging-guided siRNA delivery for personalized treatment of advanced malignancies.

Combinations of BRAF inhibitor and anti-PD-1/PD-L1 antibody improve survival and tumour immunity in an immunocompetent model of orthotopic murine anaplastic thyroid cancer.

BACKGROUND: Patients with anaplastic thyroid cancer (ATC) have an extremely poor prognosis despite aggressive multimodal therapy. ATC has a high prevalence of BRAFV600E mutations and is associated with an immunosuppressive microenvironment; we previously demonstrated that the combination of BRAF inhibitor and checkpoint inhibitor immunotherapy synergistically reduce tumour volume in an immunocompetent mouse model of orthotopic ATC. METHODS: We again utilised our mouse model of ATC to assess the combination of BRAFV600E inhibitor PLX4720 and anti-PD-L1 or anti-PD-1 antibody on survival, and performed immune cell profiling of lymphoid and myeloid-lineage cells during maximal treatment response and tumour regrowth. RESULTS: Combination therapy dramatically improved mouse survival. Maximal tumour reduction was associated with increases in the number and cytotoxicity of CD8+ T cells and NK cells, as well as increases in mostly M1-polarised tumour-associated macrophages (TAM) and decreases in myeloid-derived suppressor-like cells. Regrowth of tumour occurred after 2-3 weeks of ongoing combination therapy, and was most significantly associated with decreased TAMs and a dramatic increase in M2-polarisation. CONCLUSIONS: Combination of PLX4720 and anti-PD-L1/PD-1 antibody dramatically reduced tumour volume, prolonged survival and improved the anti-tumour immune profile in murine ATC. Tumour growth inevitably recurred and demonstrated re-emergence of an immunosuppressive tumour microenvironment.

Ensuring Equity, Diversity, and Inclusion in Academic Surgery: An American Surgical Association White Paper.

OBJECTIVE: The leadership of the American Surgical Association (ASA) appointed a Task Force to objectively address issues related to equity, diversity, and inclusion with the discipline of academic surgery. SUMMARY OF BACKGROUND DATA: Surgeons and the discipline of surgery, particularly academic surgery, have a tradition of leadership both in medicine and society. Currently, we are being challenged to harness our innate curiosity, hard work, and perseverance to address the historically significant deficiencies within our field in the areas of diversity, equity, and inclusion. METHODS: The ASA leadership requested members to volunteer to serve on a Task Force to comprehensively address equity, diversity, and inclusion in academic surgery. Nine work groups reviewed the current literature, performed primary qualitative interviews, and distilled available guidelines and published primary source materials. A work product was created and published on the ASA Website and made available to the public. The full work product was summarized into this White Paper. RESULTS: The ASA has produced a handbook entitled: Ensuring Equity, Diversity, and Inclusion in Academic Surgery, which identifies issues and challenges, and develops a set of solutions and benchmarks to aid the academic surgical community in achieving these goals. CONCLUSION: Surgery must identify areas for improvement and work iteratively to address and correct past deficiencies. This requires honest and ongoing identification and correction of implicit and explicit biases. Increasing diversity in our departments, residencies, and universities will improve patient care, enhance productivity, augment community connections, and achieve our most fundamental ambition-doing good for our patients.

Denaturation-Enhanced Droplet Digital PCR for Liquid Biopsies.

BACKGROUND: Although interest in droplet-digital PCR technology (ddPCR) for cell-free circulating DNA (cfDNA) analysis is burgeoning, the technology is compromised by subsampling errors and the few clinical targets that can be analyzed from limited input DNA. The paucity of starting material acts as a "glass ceiling" in liquid biopsies because, irrespective how analytically sensitive ddPCR techniques are, detection limits cannot be improved past DNA input limitations. METHODS: We applied denaturation-enhanced ddPCR (dddPCR) using fragmented genomic DNA (gDNA) with defined mutations. We then tested dddPCR on cfDNA from volunteers and patients with cancer for commonly-used mutations. gDNA and cfDNA were tested with and without end repair before denaturation and digital PCR. RESULTS: By applying complete denaturation of double-stranded DNA before ddPCR droplet formation the number of positive droplets increased. dddPCR using gDNA resulted in a 1.9-2.0-fold increase in data-positive droplets, whereas dddPCR applied on highly-fragmented cfDNA resulted in a 1.6-1.7-fold increase. End repair of cfDNA before denaturation enabled cfDNA to display a 1.9-2.0-fold increase in data-positive signals, similar to gDNA. Doubling of data-positive droplets doubled the number of potential ddPCR assays that could be conducted from a given DNA input and improved ddPCR precision for cfDNA mutation detection. CONCLUSIONS: dddPCR is a simple and useful modification in ddPCR that enables extraction of more information from low-input clinical samples with minor change in protocols. It should be applicable to all ddPCR platforms for mutation detection and, potentially, for gene copy-number analysis in cancer and prenatal screening.