Perioperative and oncological outcomes following robotic en bloc multivisceral resection for colorectal cancer

AIM

As multidisciplinary treatment strategies for colorectal cancer have improved, aggressive surgical resection has become commonplace. Multivisceral and extended resections offer curative-intent resection with significant survival benefit. However, limited data exist regarding the feasibility and oncological efficacy of performing extended resection via a minimally invasive approach. The aim of this study was to determine the perioperative and long-term outcomes following robotic extended resection for colorectal cancer.

METHOD

We describe the population of patients undergoing robotic multivisceral resection for colorectal cancer at our single institution. We evaluated perioperative details and investigated short- and long-term outcomes, using the Kaplan-Meier method to analyse overall and recurrence-free survival.

RESULTS

Among the 86 patients most tumours were T3 (47%) or T4 (47%) lesions in the rectum (78%). Most resections involved the anterior compartment (72%): bladder (n = 13), seminal vesicle/vas deferens (n = 27), ureter (n = 6), prostate (n = 15) and uterus/vagina/adnexa (n = 27). Three cases required conversion to open surgery; 10 patients had grade 3 complications. The median hospital stay was 4 days. Resections were R0 (>1 mm) in 78 and R1 (0 to ≤1 mm) in 8, with none being R2. The average nodal yield was 26 and 48 (55.8%) were pN0. Three-year overall survival was 88% and median progression-free survival was 19.4 months. Local recurrence was 6.1% and distant recurrence was 26.1% at 3 years.

CONCLUSION

Performance of multivisceral and extended resection on the robotic platform allows patients the benefit of minimally invasive surgery while achieving oncologically sound resection of colorectal cancer.

Rectal Adenocarcinoma Presenting as a Cervical Mass: A Case Report

BACKGROUND Invasive cervical tumors are often seen in clinical practice. However, there are multiple structures within the pelvis, and invasion of the cervix from another site must be included in the differential diagnosis. In such cases, a multidisciplinary approach is needed to define the organ of tumor origin. Ensuring proper staging and histologic analysis are critical for optimal management. CASE REPORT We present a case of a 68-year-old woman who presented to her gynecologist with painless post-menopausal vaginal bleeding. She was diagnosed with a locally aggressive cervical adenocarcinoma, which was histologically confirmed by an in-office biopsy. She was referred to the gynecologic oncology service at a tertiary care hospital for definitive management, where a thorough clinical workup was performed. Physical exam revealed that the mass had invaded the anterior rectal wall. Through a multidisciplinary approach and a repeat biopsy, she was correctly diagnosed with an invasive rectal adenocarcinoma. She was treated with neoadjuvant chemoradiotherapy and underwent curative surgery. Had she been incorrectly treated as having a primary cervical adenocarcinoma, there would have been no role for surgery. The change in the organ of primary drastically altered the patient's management and outcome. She is currently undergoing surveillance with cross-sectional imaging. CONCLUSIONS Cervical masses originating from non-gynecologic organs can be difficult to differentiate on physical exam and histologic analysis. When a mass involves the rectum, an invasive primary rectal adenocarcinoma must be included in the differential. This will have a significant impact on patient management and ultimately on patient survival.

Differential Spatial Gene and Protein Expression Associated with Recurrence Following Chemoradiation for Localized Anal Squamous Cell Cancer

The identification of transcriptomic and protein biomarkers prognosticating recurrence risk after chemoradiation of localized squamous cell carcinoma of the anus (SCCA) has been limited by a lack of available fresh tissue at initial presentation. We analyzed archival FFPE SCCA specimens from pretreatment biopsies prior to chemoradiation for protein and RNA biomarkers from patients with localized SCCA who recurred (N = 23) and who did not recur (N = 25). Tumor cells and the tumor microenvironment (TME) were analyzed separately to identify biomarkers with significantly different expression between the recurrent and non-recurrent groups. Recurrent patients had higher mean protein expression of FoxP3, MAPK-activation markers (BRAF, p38-MAPK) and PI3K/Akt activation (phospho-Akt) within the tumor regions. The TME was characterized by the higher protein expression of immune checkpoint biomarkers such as PD-1, OX40L and LAG3. For patients with recurrent SCCA, the higher mean protein expression of fibronectin was observed in the tumor and TME compartments. No significant differences in RNA expression were observed. The higher baseline expression of immune checkpoint biomarkers, together with markers of MAPK and PI3K/Akt signaling, are associated with recurrence following chemoradiation for patients with localized SCCA. These data provide a rationale towards the application of immune-based therapeutic strategies to improve curative-intent outcomes beyond conventional therapies for patients with SCCA.

Unsupervised machine learning improves risk stratification of patients with visual normal SPECT myocardial perfusion imaging assessments

Background

Unsupervised machine learning has the potential to identify new cardiovascular phenotypes and more accurately assess individual risk in an unbiased fashion.

Purpose

We aimed to use unsupervised learning to identify, analyze, and risk-stratify subgroups of patients with normal perfusion by visual interpretation on single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

Methods

We included consecutive patients with visual normal clinical assessment (summed stress score of 0) from the multicenter (9 sites), REFINE SPECT registry. We considered 23 clinical, 17 image-acquisition, and 26 imaging variables. Optimal dimensionality reduction (Uniform Manifold Approximation and Projection), clustering (Gaussian Mixture Model), and number of clusters were selected to maximize the silhouette coefficient (how similar a patient is to those in their own cluster compared to other clusters). Risk stratification for all-cause mortality (ACM) and major adverse cardiac events (MACE) was assessed within these clusters and compared to risk stratification by quantitative ischemia (<5%, 5–10%, >10%) using Kaplan-Meier curves and Cox Proportional-Hazards analysis.

Results

In total, 17,527 (of 30,351) patients in the registry had visually normal perfusion, 49.7% female, median age of 64 [55, 72] years. There were 1,138 ACM events and 2,091 MACE events with a median follow-up of 4.1 [2.9, 5.7] years. Unsupervised learning provided better risk stratification for both ACM and MACE compared to quantitative ischemia (Figure). Notably, the high-risk cluster by unsupervised learning had a hazard ratio (HR) of 9.5 (95% confidence interval [CI]: 7.7–11.7) compared to 1.4 (95% CI: 1.1–1.9) for quantitative ischemia >10%. The high-risk cluster had proportionally more women (45% [low-risk], 51% [medium-risk], 57% [high-risk], all p<0.001), higher body mass indices (26.9, 27.4, 29.6, all p<0.001), prevalence of diabetes (17%, 22%, 33%, all p<0.001), and abnormal rest ECGs (30%, 43%, 64%, p<0.001); with lower rates of family history of coronary artery disease (40%, 33%, 24%, p<0.001). Patients in the low-risk cluster were more likely to undergo exercise stress (100%, 38%, 0%, all p<0.001), had lower rest peak systolic blood pressure (130, 131, 140 mmHg, all p<0.001), and higher stress peak systolic blood pressure (164, 150, 131 mmHg, all p<0.001). Patients in the high-risk cluster had higher left ventricular mass (129, 135.45, 143.9 g, all p<0.001) and stress volume (57, 59, 66 ml, all p<0.001).

Conclusion

Unsupervised learning identified new phenotypic clusters for SPECT MPI patients with visual normal assessments which provided improved risk stratification for ACM and MACE compared to SPECT ischemia. Such individualized risk assessment may allow better targeted management of patients with visually normal perfusion.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Research reported in this publication was supported by the National Heart, Lung, And Blood Institute of the National Institutes of Health under Award Number R01HL089765. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

A Not So Perfect Score: Factors Associated with the Rate of Straight Line Scoring in Oncology Training Programs

Straight line scoring (SLS), defined as trainee assessments with the same score for all evaluation items, is statistically improbable and potentially indicates inaccurate assessment. Factors contributing to higher SLS rates are unknown, and knowledge of SLS prevalence within oncologic training is lacking. SLS frequency was measured for evaluations from all Accreditation Council for Graduate Medical Education (ACGME)-accredited programs at a single cancer care institution between 2014 and 2018. SLS prevalence was estimated using hierarchical linear models (HLM) that considered characteristics of evaluator, trainee, and evaluation potentially related to SLS. Results were compared with national SLS rates. Six thousand one hundred sixty evaluations were included from 476 evaluators. Overall prevalence of SLS was 12.1% (95% CI 4.5-28.8). Residents (vs fellows) were less likely to have SLS evaluations (OR 0.5, 95% CI 0.4-0.8), though for all trainees increasing training year corresponded with increasing SLS frequency (OR 1.5, 95% CI 1.3-1.7). SLS was more common in procedural specialties compared with medical specialties (OR 2.1, 95% CI 1.1-3.8). Formative evaluations had lower SLS rates (OR 0.6, 95% CI 0.5-0.9) than summative evaluations, while milestone-based evaluations had higher rates than those that were not milestone-based (OR 1.5, 95% CI 1.03-2.2). Features of evaluators, such as subspecialty within oncology, and of trainees, such as seniority or trainee type, were related to SLS. Summative intent and milestone-based evaluations were more likely to be straight line scored. Specific evaluation scenarios at higher risk of SLS should be further examined.

Development of an Online Curriculum for Surgeons on the Use of Pelvic Magnetic Resonance Imaging in Rectal Cancer and Results of a Pilot Study

BACKGROUND

High-resolution pelvic magnetic resonance imaging (MRI) is a critical tool in the management of patients with rectal cancer. An on-line curriculum was developed for surgical trainees on the interpretation of pelvic MRI in rectal cancer for clinical staging and surgical planning.

METHODS

The online curriculum was developed using the six-step approach to curriculum development for medical education. The curriculum incorporated case-based learning, annotated videos, and narrated presentations on key aspects of pelvic MRI in rectal cancer. A pilot study was conducted to assess curriculum effectiveness among Complex General Surgical Oncology (CGSO) fellows using pre- and post-intervention assessments.

RESULTS

Of 15 eligible fellows, nine completed the pilot study (60%). The fellows' median confidence score after completing the online curriculum (40, IQR: 33-46) was significantly higher than their baseline median confidence score (23, IQR: 14-30), P = 0.0039. The total practical assessment score significantly increased from a pre-median score of 9 (IQR: 8-11) to a post-median score of 14 (IQR: 13-14), P = 0.0078. A subgroup analysis revealed a significant change in the knowledge assessment with a median score of 7 compared to a baseline median score of 4, Z = 2.64, P = 0.0078. However, the skills assessment showed no significant change.

CONCLUSIONS

The case-based online curriculum had a positive impact on CGSO fellows' knowledge and confidence in the utilization of pelvic MRI for patients with rectal cancer. This unique on-line curriculum demonstrates a mechanism to enhance shared educational collaboration across CGSO fellowships and other surgical training programs.

Colorectal cancer during pregnancy or postpartum: Case series and literature review

Background

Colorectal cancer in young adults is on the rise. This rise combined with delayed childbearing increases the likelihood of colorectal cancer diagnosed during pregnancy or in the postpartum period.

Methods

Electronic health records were used to identify individuals with colorectal cancer in pregnancy or the postpartum period from 1 August 2007 to 1 August 2019.

Results

Forty-two cases were identified. Median age at diagnosis was 33 years. Most (93%) were diagnosed in an advanced stage (III or IV) and had left-sided colorectal cancer tumors (81%). Molecular analysis was completed in 18 (43%) women with microsatellite status available in 40 (95%). The findings were similar to historical controls. Sixty percent were diagnosed in the postpartum period. Common presenting symptoms were rectal bleeding and abdominal pain.

Conclusion

Currently there is no consensus recommendation regarding how to manage colorectal cancer during pregnancy. Given the overlapping symptoms with pregnancy, patients often present with advanced disease. We encourage all health care professionals caring for pregnant women to fully evaluate women with persistent gastrointestinal symptoms to rule out colorectal cancer.

CEA as a blood-based biomarker in anal cancer

BACKGROUND

The clinical utility of a blood-based biomarker in squamous cell carcinoma of the anus (SCCA) is unknown. We analyzed carcinoembryonic antigen (CEA), a commonly employed assay for patients with colorectal adenocarcinoma, as a serum biomarker for patients with biopsy-proven SCCA.

MATERIALS AND METHODS

Medical records from 219 patients with biopsy-proven SCCA at the University of Texas MD Anderson Cancer Center were reviewed under an IRB-approved protocol from 2013 to 2020 to assess for correlations between CEA levels and corresponding clinical and pathologic characteristics.

RESULTS

The mean CEA among subgroups by clinical status at the time of presentation to our institution was highest among those patients with metastatic SCCA to visceral organs (M-V, 20.7 ng/mL), however this finding was not statistically significant by ANOVA (p = .74). By clinical subgroup, the percentage of patients with an abnormally elevated CEA was highest in those patients with metastatic disease to lymph nodes (M-L, 41.2%) followed by recurrent/unresectable SCCA (36.8%), and metastatic SCCA to visceral organs (M-V, 35.2%), and was statistically significant between groups (Fisher's exact test p = .02). Using RECIST criteria for tumor progression and disease response, the mean change in CEA for patients with progression was an increase in 19 ng/mL, compared to a change of -7.3 ng/mL in those with disease response (p = .004). We likewise assessed whether CEA levels were associated with survival outcomes for all patients with metastatic SCCA, and found no correlation between CEA and likelihood for survival in a ROC analysis (multivariate, age-adjusted analysis for CEA cutoff of 8, HR = 1.01, 95% CI 0.52-1.96).

CONCLUSIONS

Despite interesting patterns of abnormally high CEA in SCCA patients with advanced disease, and correlation of increased CEA with disease progression (and conversely decreased CEA with disease response), CEA is not associated with survival outcomes in SCCA, and is not a clinically relevant biomarker in this disease.

Abstract A47: Circulating tumor cell-defined minimal residual disease in locally advanced rectal cancer treated with multimodality therapy

Background: Current treatment for locally advanced rectal cancer (LARC) includes multimodality therapy in the neoadjuvant and adjuvant settings. Response to neoadjuvant therapy (NT) is prognostic of long-term outcomes. While long-course chemoradiation (CRT) had been the traditional NT regimen, novel regimens adding systemic therapy and/or eliminating radiation have been introduced. We examined if circulating tumor cells provide prognostic information independent of the specific treatment regimen utilized. Specifically, we aimed to define the significance of CTC-defined minimal residual disease (MRD) in LARC.

Methods: A prospective longitudinal protocol enrolled LARC patients (N=100; clinical stage II=4; stage III=96) undergoing NT. Peripheral blood was collected at baseline (t1, treatment-naive), after NT (t2, intraoperatively before tumor manipulation), after resection (t3, 2-8 weeks postoperatively), and after completion of adjuvant therapy (t4, 2-12 weeks after completion). CTC was enumerated by the CellSearch® platform within 72 hours of collection. Patients were followed for disease-free survival (DFS).

Results: At t1, CTCs were detected in 28/90 (31.1%) patients with available samples with a median CTC count of 1.5 [IQR: 1.0, 2.75]. NT consisted of long-course pelvic CRT (65%), extended NT with systemic chemotherapy and long- or short-course pelvic CRT (22%), and a radiation-sparing regimen with systemic chemotherapy only (13%). At t2, CTCs were detected in 34/75 (45.3%) patients with a median CTC count of 1 [IQR: 1, 1]. Type of NAT did not correlate with CTC positivity (p=0.637). Ten (9.4%) patients declined surgery, while cPR occurred in 12/93 (12.9%) surgical patients. Postoperatively (t3), CTC was detected in 12/47 (25.5%) patients, with a median count of 1.5 (IQR: 1.0-3.0). After completing adjuvant chemotherapy (t4), only 3/29 (10.3%) patients had detectable CTC. With a median follow-up of 47.50 months from diagnosis for the entire cohort, CTC positivity at t4 significantly stratified DFS (p=0.035).

Conclusions: One third of locally advanced RC patients harbored detectable CTCs at baseline. CTC detection after completion of curative-intent multimodality therapy (i.e., MRD) correlated with long-term DFS.

Citation Format: Lucas Lee, Carol Hall, Antony Lucci, Brian Bednarski, Miguel Rodriguez-Bigas, George Chang, Y. Nancy You. Circulating tumor cell-defined minimal residual disease in locally advanced rectal cancer treated with multimodality therapy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A47.

CEA as a pharmacodynamic biomarker for metastatic anal cancer

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Background: While carcinoembryonic antigen (CEA) as a tumor marker is frequently used in the management of colorectal adenocarcinoma, its clinical utility in squamous cell carcinoma of the anus (SCCA) has never been reported. Indeed, no tumor markers have been validated for monitoring tumor burden in the course of any HPV-associated malignancy like SCCA. We hypothesized that CEA levels might be preferentially elevated in patients with metastatic SCCA. Methods: Charts from 212 patients with SCCA were reviewed under an IRB-approved protocol for correlations between CEA levels and corresponding oncologic status. Clinical status was categorized as newly diagnosed non-metastatic (D), after chemoradiation with no evident remnant disease (N), recurrent/resectable SCCA (R), locally advanced/unresectable SCCA (U), metastatic SCCA to lymph nodes only (M-LN), or metastatic SCCA to visceral organs (M-V). Mean CEA levels were compared between subgroups via student t-tests, and frequencies of elevated CEA were compared via Chi-squared analyses. Results: 118 SCCA patients had metastatic disease (98 M-V, 19 M-LN). Mean CEA levels by clinical status were 5.4 (D), 2.0 (N), 2.3 (R), 4.6 (U), 6.0 (M-LN), and 22.2 (M-V), with a higher (statistically insignificant) mean CEA level in the M-V relative to other populations. However, patients with visceral metastases were more likely to have an elevated CEA at presentation (40.4%) relative to patients with newly diagnosed, non-metastatic SCCA (17.6%, p = .07) or recurrent SCCA (11.1%, p = .02). For patients with metastatic SCCA, a significant association existed between change in CEA and corresponding change in radiographic tumor dimensions (OR 24, p < 0.0001). Conclusions: Trends in CEA correlate with dynamic changes in tumor burden for patients with metastatic SCCA, and patients with metastatic SCCA were more likely to have an elevated CEA. Given that immune checkpoint blockade agents like nivolumab have proven benefit for metastatic SCCA, these data provide rationale for use of newer generation immunotherapeutic approaches like CEA-T cell bispecific antibodies, which target CEA-expressing tumors, in clinical trials for patients with metastatic SCCA.

Minimally invasive complete mesocolic excision and central vascular ligation for right colon cancer: Defining the radicality of central lymphadenectomy

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Background: Complete mesocolic excision (CME) with central vascular ligation (CVL) has been advocated for right colon cancer (RC), but the radicality of lymphadenectomy remains controversial. Optimal D2 lymphadenectomy removes all intermediate nodes with high ligation (HL) of feeding vessels, while D3 lymphadenectomy additionally exposes and retrieves nodes along ventral superior mesenteric vessels (SMA/V). We aim to evaluate minimally invasive CME-CVL, explicitly defining the radicality of central lymphadenectomy. Methods: Patients who underwent minimally invasive resection for RC between 2008 and 2016 were identified from a prospective institutional database. CME was standard. The radicality of central lymphadenectomy was defined as high ligation (HL, optimal D2) vs central node dissection (CND, D3) after review of operative reports and/or videos. A blinded radiologist evaluated the pre- and post-operative CT scans for radiographically abnormal nodes. Results: Among 200 patients, 169 (84.5%) underwent laparoscopic and 31 (15.5%) robotic resection. Central lymphadenectomy was performed as HL in 58 (29%) and as CND in 142 (71%) patients. Preoperative imaging identified abnormal D2 nodes in 33.0% and D3 nodes in 2.6%. CND was performed in 73% of those with abnormal D2 and 100% of those with abnormal D3 nodes. Pathologically positive nodes were identified in 41% (37.9% of the HL and 42.3% of the CND, p=0.64). The median number of nodes retrieved was 27 and 32, respectively. No patient had residual abnormal node on post-operative imaging. The 30 day mortality rate was 0%, and morbidity rate was 15% (4% grade 3, 11% grades 1-2). After a median of 22 months, one (0.5%) patient recurred locally at the anastomosis. Conclusions: Minimally invasive CME-CVL can be safely performed with excellent nodal yield with both optimal D2 as well as D3 lymphadenectomy. With imperfect clinical nodal staging, the near-zero local recurrence rate observed supports CME with optimal D2 lymphadenectomy as a minimum standard and D3 lymphadenectomy when radiographically abnormal nodes are identified.

Longitudinal trajectory of cancer survivorship in patients with recurrent rectal cancer: Anatomy of recurrence in relation to quality of life and pain

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Background: Multiple treatment modalities are utilized for patients with recurrent rectal cancer (RRC). While recurrent pelvic tumor can be highly symptomatic, treatments often carry significant morbidity risks. Patient reported outcomes such as quality of life (QoL) and pain can supplement traditional clinical endpoints in assessing the effectiveness of salvage treatments, and thus aid in treatment decision making. We aimed to examine the longitudinal trajectory of cancer survivorship in RRC. Methods: A prospective protocol enrolled patients diagnosed with RRC between 2008 and 2015. Participants prospectively self-reported QoL (measured by the validated EORTC QLQ-C30 and EORTC QLQ-CR29) and pain (measured by the Brief Pain Inventory, BPI), at presentation, and then every 6 months for 5 years. After accounting for repeated measures, trajectory of mean scores over time was assessed for patients amenable to surgical salvage vs those who were not, using linear mixed-effects modeling. Results: A total of 104 patients were enrolled of which 73 (70.2%) were amenable to salvage surgery with curative intent. Surgical salvage was associated with 30 day morbidity of 68.5% (13.7% and 5.5%, Grade 3 and 4 respectively). Three year overall survival was 56.7% (68.5% in surgical and 29.0% in non-surgical patients). Mean baseline QoL scores did not differ between surgical vs nonsurgical patients but were significantly impacted by the anatomical site of recurrent disease (lowest scores in posterior pelvic recurrence; P=0.012). On longitudinal analysis with a median followup of 33 months, surgically salvaged patients showed gradual sustained improvement in QoL but not pain scores. Anatomy of initial recurrence had an ongoing impact on QoL long term with posterior recurrences having the worst scores. Both QoL and pain scores worsened in patients not amendable to surgical salvage. Conclusions: Disease anatomy determines QoL at baseline and long term in patients with RRC. Surgery improves QoL but not pain in selected resectable cases.

DNA Mismatch Repair Deficiency in Rectal Cancer: Benchmarking Its Impact on Prognosis, Neoadjuvant Response Prediction, and Clinical Cancer Genetics

PURPOSE

DNA mismatch repair deficiency (dMMR) hallmarks consensus molecular subtype 1 of colorectal cancer. It is being routinely tested, but little is known about dMMR rectal cancers. The efficacy of novel treatment strategies cannot be established without benchmarking the outcomes of dMMR rectal cancer with current therapy. We aimed to delineate the impact of dMMR on prognosis, the predicted response to fluoropyrimidine-based neoadjuvant therapy, and implications of germline alterations in the MMR genes in rectal cancer.

METHODS

Between 1992 and 2012, 62 patients with dMMR rectal cancers underwent multimodality therapy. Oncologic treatment and outcomes as well as clinical genetics work-up were examined. Overall and rectal cancer-specific survival were calculated by the Kaplan-Meier method.

RESULTS

The median age at diagnosis was 41 years. MMR deficiency was most commonly due to alterations in MSH2 (53%) or MSH6 (23%). After a median follow-up of 6.8 years, the 5-year rectal cancer-specific survival was 100% for stage I and II, 85.1% for stage III, and 60.0% for stage IV disease. Fluoropyrimidine-based neoadjuvant chemoradiation was associated with a complete pathologic response rate of 27.6%. The extent of surgical resection was influenced by synchronous colonic disease at presentation, tumor height, clinical stage, and pelvic radiation. An informed decision for a limited resection focusing on proctectomy did not compromise overall survival. Five of the 11 (45.5%) deaths during follow-up were due to extracolorectal malignancies.

CONCLUSION

dMMR rectal cancer had excellent prognosis and pathologic response with current multimodality therapy including an individualized surgical treatment plan. Identification of a dMMR rectal cancer should trigger germline testing, followed by lifelong surveillance for both colorectal and extracolorectal malignancies. We herein provide genotype-specific outcome benchmarks for comparison with novel interventions.

Developing a research skill set

The recent decades have witnessed a significant expansion in the diversity of career paths within academic surgery. Although the skills for providing exemplary surgical care and for maintaining a strong work ethic are the foundations of an academic surgeon, deliberate career planning and organized acquisition of research skills contribute to the success of an academic career. In this article, we identify a set of core academic skills and propose a framework for acquiring them. We also describe specific career paths within academic surgery and provide an overview of the opportunities for acquiring specific skill sets. The development of an academic career is challenging, and firm knowledge of the personal motivations will sustain and endure the time needed for acquiring the needed skills.

Abstract 256: Downregulation of Pim-3 kinase inhibits cell growth and chemosensitizes pancreatic cancer cells to gemcitabine

Pancreatic ductal adenocarcinoma (PDAC) is the most common cancer of the pancreas, comprising over 85% of all cases. PDAC has a relative 1-year survival rate of 24% and a 5-year survival rate of 5%. Recent clinical studies indicate that patients with advanced pancreatic cancer show a 12% tumor response rate after treatment with the chemotherapeutic drug gemcitabine. Even in combination with other chemotherapeutic agents such as erlotinib, survival rates are only increased by a few weeks. Past studies have shown that members of the oncogenic Pim kinase family are aberrantly expressed in a variety of solid tumors, including prostate and pancreatic cancers. Most recently, Pim kinase has been correlated with chemoresistance in prostate cancer cells. Our study aimed to investigate the role of Pim-3 kinase in the chemoresistance of PDAC cancer cells to gemcitabine. We hypothesize that inhibition of Pim-3 will decrease cell growth and sensitize PDAC cells to gemcitabine treatment. Initially, we confirmed by immunohistochemistry and western blot analysis that Pim-3 is aberrantly expressed in PDAC tissues and cell lines, respectively. We found that inhibition of Pim-3 expression by shRNA decreased PDAC cell growth and resulted in an accumulation of cells in G1 or S phase of the cell cycle. Additionally, we demonstrated that PDAC cells expressing Pim-3 shRNA had increased apoptosis after gemcitabine treatment compared to controls. To determine a possible mechanism for this resensitization of PDAC cells to gemcitabine, we measured multidrug resistance (MDR)1 activity in the Pim-3 shRNA cells. We found that inhibition of Pim-3 protein expression in PDAC cells promoted gemcitabine sensitivity, in part, by lowering MDR1 activity. Our results suggest that downregulation of Pim-3 potentiates the efficacy of gemcitabine in combating pancreatic cancer. These findings support the idea that inhibiting Pim kinases, in combination with chemotherapeutic agents, could play an important role in pancreatic cancer treatment by targeting the clinical problem of chemoresistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 256. doi:10.1158/1538-7445.AM2011-256

Isoform-specific upregulation of palladin in human and murine pancreas tumors

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with a characteristic pattern of early metastasis, which is driving a search for biomarkers that can be used to detect the cancer at an early stage. Recently, the actin-associated protein palladin was identified as a candidate biomarker when it was shown that palladin is mutated in a rare inherited form of PDA, and overexpressed in many sporadic pancreas tumors and premalignant precursors. In this study, we analyzed the expression of palladin isoforms in murine and human PDA and explored palladin's potential use in diagnosing PDA. We performed immunohistochemistry and immunoblot analyses on patient samples and tumor-derived cells using an isoform-selective monoclonal antibody and a pan-palladin polyclonal antibody. Immunoblot and real-time quantitative reverse transcription-PCR were used to quantify palladin mRNA levels in human samples. We show that there are two major palladin isoforms expressed in pancreas: 65 and 85–90 kDa. The 65 kDa isoform is expressed in both normal and neoplastic ductal epithelial cells. The 85–90 kDa palladin isoform is highly overexpressed in tumor-associated fibroblasts (TAFs) in both primary and metastatic tumors compared to normal pancreas, in samples obtained from either human patients or genetically engineered mice. In tumor-derived cultured cells, expression of palladin isoforms follows cell-type specific patterns, with the 85–90 kDa isoform in TAFs, and the 65 kDa isoform predominating in normal and neoplastic epithelial cells. These results suggest that upregulation of 85–90 kDa palladin isoform may play a role in the establishment of the TAF phenotype, and thus in the formation of a desmoplastic tumor microenvironment. Thus, palladin may have a potential use in the early diagnosis of PDA and may have much broader significance in understanding metastatic behavior.

Abstract 3104: The role of Pim-3 kinase in NF-κB signaling and transformation of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the 4th most common cause of cancer deaths in the United States. Due to the aggressive nature of this cancer and the lack of biomarkers for early detection, the incidence and mortality rates for PDAC are nearly equivalent. A better understanding of the molecular mechanisms leading to the development of pancreatic cancer remains a major goal for defining appropriate treatment strategies. Past studies have shown that the proto-oncogene Pim-3 kinase is expressed in pancreatic cancer and is able to phosphorylate the pro-apoptotic protein Bad to block Bad-mediated apoptosis in human pancreatic cancer cell lines. With these and other observations implicating Pim kinases as oncogenes and inhibitors of apoptosis, the purpose of our study is to further characterize the functional significance of Pim-3 in PDAC growth as well as identify possible downstream targets. We hypothesize that inhibition of Pim-3 signaling will be an effective approach for antagonizing the aberrant growth of pancreatic cancer. Initially, we confirmed by immunohistochemistry that Pim-3 protein is aberrantly expressed in human pancreatic cancer and pancreatitis tissue and is constitutively expressed in a panel of human pancreatic cancer cell lines. Also, we found that suppression of Pim-3 by shRNAs significantly decreased cell growth and caused a reduction in invasion of pancreatic cancer cells in Matrix-gel. To our knowledge, this is the first time that any of the Pims have been associated with invasion in pancreatic cancer. Most recently, other members of the Pim kinase family have been shown to activate NF-κB in cancer. From our studies, we observed that suppression of Pim-3 upregulated IκBα and decreased phospho-NF-κB p65 (Ser536), suggesting an effect on NF-κB transcription activity. Our results indicate the importance of Pim-3 in various aspects of transformation of pancreatic cancer and how NF-κB may be a potential downstream target of Pim-3 signaling in PDAC. These findings will allow us to critically validate Pim kinases as novel biomarkers and therapeutic targets for pancreatic cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3104.

Palladin expression contributes to invasive motiliy in metastatic breast cancer cells

Abstract #6018

Background: Cancer metastasis involves multiple actin-dependent steps, including intravasation , extravasation, and adhesion. Therefore, it is important to understand the molecular mechanisms that control cytoskeletal dynamics in metastatic cells. Palladin is an actin-binding protein that functions as a key molecular scaffold involved in actin organization. Recent studies showed that (1) a mutation in palladin is linked to a rare form of familial pancreatic cancer, (2) palladin is overexpressed in many sporadic pancreatic tumors, and (3) palladin is upregulated in pancreatic tumor-associated fibroblasts. However, palladin's functions in other invasive cancers have not been well elucidated.&#x2028; Methods: Three primary human breast cancer specimens, three metastatic breast cancer specimens and three samples of benign breast tissue were obtained from the UNC Tissue Procurement Facility. Extracts were analyzed using western blots. Eight human breast cancer cell lines, which differ in their metastatic potential, were used: T47D, BT474, ZR75.1 and MCF-7, BT549, Hs578T, MDA-MB-231 and SUM159. Western blots were performed to determine the level of palladin in all cells lines. siRNA and virus infection approaches were used to reduce and overexpress palladin levels, respectively. Cell migration was analyzed in transwell inserts. Invasion experiments were conducted in Matrigel invasion chambers. Podosome formation was induced with the phorbol ester PDBu.&#x2028; Results: Immunoblot analysis revealed that palladin levels are higher overall in primary tumors and metastases, when compared to benign breast tissue. Immunohistochemistry showed that palladin staining is associated with ductal epithelial cells and tumor cells. In breast cancer cells, palladin expression closely correlates with metastatic potential: palladin levels were ∼16 fold higher in invasive cells than in non-invasive cells. Furthermore, knockdown of palladin resulted in a significant reduction in the ability of SUM159 cells to migrate through a transwell filter, and to invade through a layer of Matrigel. Phorbol ester treatment stimulated the formation of palladin-containing podosomes in SUM159 and MDA-MB-231, but not MCF7 cells. Palladin knockdown also impaired the ability of SUM159 cells to assemble podosomes. Palladin overexpression promotes podosome formation but does not affect cell migration.&#x2028; Discussion: Our results show that palladin plays an important role in podosome formation, and thus high levels of palladin expression may contribute to the invasive motility of metastatic breast cancer cells by facilitating the assembly of these structures. Our results also show that overexpression of palladin alone is not sufficient to trigger enhanced invasive motility in cultured human breast cancer cells. These results support a model in which a cohort of genes are coordinately upregulated in metastatic cells, contributing to specific aspects of invasive cell motility.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6018.

Palladin contributes to invasive motility in human breast cancer cells

Cancer metastasis involves multiple steps including detachment of the metastatic cells from neighboring cells, the acquisition of motility and invasion to other tissue. All of these steps require the reorganization of the actin cytoskeleton. In this study, we found that the protein palladin, a molecular scaffold with an important function in actin organization, is expressed at higher overall levels in tumors compared to benign breast tissue, and also significantly higher in four invasive breast cancer cell lines when compared to four non-invasive cell lines. In addition, we found that palladin plays a key role in the formation of podosomes. Podosomes are actin-rich structures that function in adhesion and matrix degradation and have been found in many invasive cell types. Our results show that phorbol ester treatment stimulated the formation of palladin-containing podosomes in invasive, but not in non-invasive cell lines. More importantly, palladin knockdown resulted in decreased podosome formation and a significant reduction in transwell migration and invasive motility. Palladin overexpression induced podosome formation in the non-invasive MCF7 cells, which are otherwise unable to form podosomes, suggesting that palladin plays a critical role in the assembly of podosomes. Overall, these results indicate that palladin overexpression contributes to the invasive behavior of metastatic cells.

Increased depth of subcutaneous fat is protective against abdominal injuries in motor vehicle collisions

The objective of this study was to determine the effect of differences in subcutaneous fat depth on adult injury patterns in motor vehicle collisions. Sixty-seven consecutive adult crash subjects aged 19-65 who received computed tomography of their chest, abdomen and pelvis as part of their medical evaluation and who consented to inclusion in the Crash Injury Research Engineering Network (CIREN) study were included. Subcutaneous fat was measured just lateral to the rectus abdominus muscle in a transverse section taken through the subject at the level of L4. Women had significantly greater subcutaneous fat depth than men. Increased subcutaneous fat depth was associated with significantly decreased injury severity to the abdominal region of females. A similar trend was noted in males although it did not reach statistical significance. Our findings suggest that increased subcutaneous fat may be protective against injuries by cushioning the abdominal region against injurious forces in motor vehicle collisions.

In vitro processing of the proproteins GrdE of protein B of glycine reductase and PrdA of D-proline reductase from Clostridium sticklandii: formation of a pyruvoyl group from a cysteine residue

GrdE and PrdA of Clostridium sticklandii are subunits of glycine reductase and D-proline reductase, respectively, that are processed post-translationally to form a catalytic active pyruvoyl group. The cleavage occurred on the N-terminal side of a cysteine residue, which is thus the precursor of a pyruvoyl moiety. Both proproteins could be over-expressed in Escherichia coli and conditions were developed for in vitro processing. GrdE could be expressed as full-size protein, whereas PrdA had to be truncated N-terminally to achieve successful over-expression. Both proproteins were cleaved at the in vivo observed cleavage site after addition of 200 mM NaBH4 in Tris buffer (pH 7.6) at room temperature as analysed by SDS/PAGE and MS. Cleavage of GrdE was observed with a half-time of approximately 30 min. Cys242, as the precursor of the pyruvoyl group in GrdE, was changed to alanine, serine, or threonine by site-directed mutagenesis. The Cys242-->Ser and Cys242-->Thr mutant proteins were also cleaved under similar conditions with extended half-times. However, the Cys242-->Ala mutant protein was not cleaved indicating a pivotal role of the thiol group of cysteine or hydroxyl group of serine and threonine during the processing of pyruvoyl group-dependent reductases.

Rapid and simultaneous activation of Stat3 and production of interleukin 6 in resuscitated hemorrhagic shock

The inflammatory response of the liver to hemorrhagic shock includes the production of acute phase proteins and a variety of mediators, such as the cytokine interleukin (IL)-6. The transcription of acute phase protein genes in hepatocytes has been shown to be activated by Stat3, one of six distinct signal transducers and activators of transcription (STAT) proteins. IL-6 signals through activation of Stat3. In this study, we examined whether or not Stat3 was activated and IL-6 mRNA produced in the liver of rats subjected to hemorrhagic shock and whether or not both phases of shock, the ischemic and the resuscitation phases, were required. We report here that Stat3 activation and increased IL-6 expression required resuscitation and displayed identical kinetics following resuscitation, suggesting that liver production of IL-6 was responsible for liver Stat3 activation in hemorrhagic shock.

Alfentanil's analgesic, respiratory, and cardiovascular actions in relation to dose and plasma concentration in unanesthetized dogs

Relationships between plasma concentrations of alfentanil and its analgesic, respiratory, and cardiovascular effects were determined in dogs. To avoid drug interaction, trained, unanesthetized, spontaneously breathing dogs were used. After a control period in the awake state, alfentanil was injected in increasing amounts (10, 20, 80, 160, and 320 micrograms/kg) at 5-min intervals to a total dose of 590 micrograms/kg administered over 20 min. The effects were observed on pain responses (heart rate and blood pressure changes and somatic reactions to tail clamping), respiration (respiratory rate, oxygen consumption [VO2], blood gas tensions) and circulation (heart rate and blood pressure). The plasma concentration-effect curves, derived by relating the changes in multiple variables from the awake state to the corresponding plasma concentrations (range 8-5079 ng/ml), plateaued at and around 200 ng/ml during the injection period but were displaced in parallel to two-fold higher concentrations during recovery, which resembles acute tolerance. At maximally effective analgesic concentrations, which precipitated profound cardiorespiratory slowing with conspicuous hypoxemia, the VO2 of 4.4 +/- 0.3 ml X kg-1 X min-1 corresponded with the calculated metabolic rate but increased to 6.3 +/- 1.6 ml X kg-1 during recovery. The analgesic action of alfentanil, which cannot be separated from its depressant cardiorespiratory effects and maximally effective analgesic concentrations (between 200 and 400 ng/ml), apparently does not jeopardize the adequacy of tissue oxygenation in dogs.