The Enderstruder: An accessible open-source syringe extruder compatible with Ender series 3D printers

Bioprinting has enabled the precise spatiotemporal deposition of cells and biomaterials, opening new avenues of research in tissue engineering and regenerative medicine. Although several open-source syringe extruder adaptations for bioprinters have been published and adopted by end users, only one has been specifically adapted for the Ender series, an affordable and open-source line of thermoplastic 3D printers. Here, we introduce the Enderstruder, a cost-effective extruder attachment that uses a standard 10 mL BD syringe, positions the stepper motor at the level of the gantry, enhances x-axis stability with a linear rail, and uses the originally included stepper motor, resulting in reduced cost and simplified assembly. Furthermore, we present an iterative process to fine-tune printing profiles for high-viscosity biomaterial inks. To facilitate the implementation of our work by other researchers, we provide fully editable Cura profiles for five commonly used biomaterials. Using these five materials to validate and characterize our design, we employ the Enderstruder to print established calibration patterns and complex shapes. By presenting the Enderstruder and its iterative development process, this study contributes to the growing repository of open-source bioprinting solutions, fostering greater accessibility and affordability for researchers in tissue engineering.

Biallelic KITLG variants lead to a distinct spectrum of hypomelanosis and sensorineural hearing loss

Background

Pathogenic variants in KITLG, a crucial protein involved in pigmentation and neural crest cell migration, cause non‐syndromic hearing loss, Waardenburg syndrome type 2, familial progressive hyperpigmentation and familial progressive hyper‐ and hypopigmentation, all of which are inherited in an autosomal dominant manner.

Objectives

To describe the genotypic and clinical spectrum of biallelic KITLG‐variants.

Methods

We used a genotype‐first approach through the GeneMatcher data sharing platform to collect individuals with biallelic KITLG variants and reviewed the literature for overlapping reports.

Results

We describe the first case series with biallelic KITLG variants; we expand the known hypomelanosis spectrum to include a ‘sock‐and‐glove‐like’, symmetric distribution, progressive repigmentation and generalized hypomelanosis. We speculate that KITLG biallelic loss‐of‐function variants cause generalized hypomelanosis, whilst variants with residual function lead to a variable auditory‐pigmentary disorder mostly reminiscent of Waardenburg syndrome type 2 or piebaldism.

Conclusions

We provide consolidating evidence that biallelic KITLG variants cause a distinct auditory‐pigmentary disorder. We evidence a significant clinical variability, similar to the one previously observed in KIT‐related piebaldism.

A phase 1/2 clinical trial of the nitric oxide synthase inhibitor L-NMMA and taxane for treating chemoresistant triple-negative breast cancer

[Figure: see text].

A randomized, controlled phase II trial of neoadjuvant ado-trastuzumab emtansine, lapatinib, and nab-paclitaxel versus trastuzumab, pertuzumab, and paclitaxel in HER2-positive breast cancer (TEAL study)

Background

Neoadjuvant dual human epidermal growth factor receptor (HER2) blockade with trastuzumab and pertuzumab plus paclitaxel leads to an overall pathologic complete response (pCR) rate of 46%. Dual HER2 blockade with ado-trastuzumab emtansine (T-DM1) and lapatinib plus nab-paclitaxel has shown efficacy in patients with metastatic HER2-positive breast cancer. To test neoadjuvant effectiveness of this regimen, an open-label, multicenter, randomized, phase II trial was conducted comparing T-DM1, lapatinib, and nab-paclitaxel with trastuzumab, pertuzumab, and paclitaxel in patients with early-stage HER2-positive breast cancer.

Methods

Stratification by estrogen receptor (ER) status occurred prior to randomization. Patients in the experimental arm received 6 weeks of targeted therapies (T-DM1 and lapatinib) followed by T-DM1 every 3 weeks, lapatinib daily, and nab-paclitaxel weekly for 12 weeks. In the standard arm, patients received 6 weeks of trastuzumab and pertuzumab followed by trastuzumab weekly, pertuzumab every 3 weeks, and paclitaxel weekly for 12 weeks. The primary objective was to evaluate the proportion of patients with residual cancer burden (RCB) 0 or I. Key secondary objectives included pCR rate, safety, and change in tumor size at 6 weeks. Hypothesis-generating correlative assessments were also performed.

Results

The 30 evaluable patients were well-balanced in patient and tumor characteristics. The proportion of patients with RCB 0 or I was higher in the experimental arm (100% vs. 62.5% in the standard arm, p = 0.0035). In the ER-positive subset, all patients in the experimental arm achieved RCB 0-I versus 25% in the standard arm (p = 0.0035). Adverse events were similar between the two arms.

Conclusion

In early-stage HER2-positive breast cancer, the neoadjuvant treatment with T-DM1, lapatinib, and nab-paclitaxel was more effective than the standard treatment, particularly in the ER-positive cohort.

Trial registration

Clinicaltrials.gov NCT02073487, February 27, 2014.

Abstract P6-17-26: Care 001: multi-center randomized open-label phase II trial of neoadjuvant trastuzumab emtansine (T-DM1) in combination with lapatinib and nab-paclitaxel compared with paclitaxel, trastuzumab and pertuzumab in HER2-neu over-expressed breast cancer patients (TEAL study)

Background: We conducted a multicenter, randomized open-label phase II neoadjuvant study of trastuzumab-emtansine (T-DM1), Lapatinib (L) and Nab Paclitaxel (Nab-P) compared to standard of care (SOC) Paclitaxel (Pac), Trastuzumab (T), and Pertuzumab (P) in patients with HER2 over-expressed breast cancer.

Methods: Patients in the experimental arm received a biologic window of targeted therapies alone for 6 weeks (T-DM1 and L) followed by T-DM1 3.0 mg/kg Q3W, L 750mg oral daily and Nab-P 80 mg/m2 weekly (QW) X 12 weeks. Patients in SOC arm received targeted therapies alone for 6 weeks (T and P) followed by Pac 80mg/m2QW, T 2mg/kg QW, and P 420mg Q3W X 12 weeks. The primary objective was to evaluate the proportion of patients with residual cancer burden (RCB) 0 or 1. Key secondary objectives included correlative assessments of PIK3CA mutations, PTEN expression, and HER2 subtypes which are being reported.

Results: Thirty of the 33 enrolled patients were evaluable. Patient demographics were well balanced. HER2 subtypes and altered PIK3CA (low PTEN or PIK3CA mutations) pathway were not statistically different between both arms. We have previously reported that all patients achieved RCB 0 & I in the T-DM1, L and Nab-P arm, compared to SOC (100% vs. 62.5%, p 0.0035). In the SOC arm, the 6 week change in tumor size on breast MRI during targeted biologic window treatment is significantly different between the responders and non-responders based on two-sided Wilcoxon rank-sum test (p =0.0065). Consistent with literature, among ER positive patients treated with SOC, PTEN low expressers were less likely to respond (0%, 0 of 2) than PTEN high expressers (67%, 2 of 3). In the experimental arm, all patients responded regardless of PTEN. There was only 1 PIK3CA mutation on the experimental arm where all responded.

Table 1:Breast MRI Tumor Size Standard of Care ArmResponseNMeanStandard Deviation95% CL MeanMinimumMaximumNo6-0.13330.4457-0.60110.3344-1.00.3Yes52.58001.88330.24154.91850.24.9Sixteen patients total were present in standard of care arm but 5 had incomplete imaging data.

Conclusions: TDM1 plus L and Nab-P therapy was well tolerated with noteworthy responses in all patients, including in PTEN low expressers. Change in tumor size at 6 weeks of biologic therapies was significant between responders and non-responders and can be evaluated as a surrogate for future studies.

Citation Format: Creamer SL, Patel TA, Ensor JE, Rodriguez AA, Niravath PA, Darcourt JG, Kaklamani VG, Meisel JL, Li X, Zhao J, Kuhn JG, Rosato RR, Qian W, Belcheva A, Boone T, Chang J. Care 001: multi-center randomized open-label phase II trial of neoadjuvant trastuzumab emtansine (T-DM1) in combination with lapatinib and nab-paclitaxel compared with paclitaxel, trastuzumab and pertuzumab in HER2-neu over-expressed breast cancer patients (TEAL study) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-26.

Identification of Incidental Germline Mutations in Patients With Advanced Solid Tumors Who Underwent Cell-Free Circulating Tumor DNA Sequencing

PURPOSE

To determine the potential for detection of incidental germline cancer predisposition mutations through cell-free DNA (cfDNA) analyses in patients who underwent solid tumor somatic mutation evaluation.

PATIENTS AND METHODS

Data were evaluated from 10,888 unselected patients with advanced (stage III/IV) cancer who underwent Guardant360 testing between November 2015 and December 2016. The main outcome was prevalence of putative germline mutations identified among 16 actionable hereditary cancer predisposition genes.

RESULTS

More than 50 cancer types were studied, including lung (41%), breast (19%), colorectal (8%), prostate (6%), pancreatic (3%), and ovarian (2%). Average patient age was 63.5 years (range, 18 to 95 years); 43% were male. One hundred and fifty-six individuals (1.4%) had suspected hereditary cancer mutations in 11 genes. Putative germline mutations were more frequent in individuals younger than 50 years versus those 50 years and older (3.0% v 1.2%, respectively; P < .001). Highest yields of putative germline findings were in patients with ovarian (8.13%), prostate (3.46%), pancreatic (3.34%), and breast (2.2%) cancer. Putative germline mutation identification was consistent among 12 individuals with multiple samples. Patients with circulating tumor DNA copy number variation and/or reversion mutations suggestive of functional loss of the wild-type allele in the tumor DNA also are described.

CONCLUSION

Detection of putative germline mutations from cfDNA is feasible across multiple genes and cancer types without prior mutation knowledge. Many mutations were found in cancers without clear guidelines for hereditary cancer genetic counseling/testing. Given the clinical significance of identifying hereditary cancer predisposition for patients and their families as well as targetable germline alterations such as in BRCA1 or BRCA2, research on the best way to validate and return potential germline results from cfDNA analysis to clinicians and patients is needed.

Abstract P1-02-06: Serial monitoring of circulating tumor DNA in patients with metastatic breast cancer

Background: For patients with MBC, there is currently no evidence that changing therapy on the basis of biomarker results improves outcome. Clinical benefit of treatment is defined as complete response, objective response, or stable disease as determined by RECIST criteria on radiological evaluation. Serial measurements of serum biomarkers such as CA2729 and CTCs have proven unsuccessful in predicting clinical benefit. Circulating tumor DNA(ctDNA) has emerged as a potential biomarker that may predict response to therapy or progression of disease. The present retrospective study was conducted to evaluate the relationship between change in ctDNA with clinical benefit determined by clinical and radiological evaluations of patients with MBC patients.

Methods: We conducted a retrospective, single-institutional study to determine if serial monitoring of ctDNA allele frequency levels predict clinical benefit of a treatment. 55 patients with measurable MBC who had serial monitoring of ctDNA between August 2014 and May 2016 were included. The median age was 55.9 (27–94) years). Clinical outcomes were determined as per standard guidelines. The analysis was performed on all cases that had serial measurements of ctDNA with no change in therapy in between and the repeat blood draw was done within 30 days of repeat radiographic evaluation. The dataset contained 125 observations from 48 unique patients. The relationship between the change in ctDNA and clinical benefit was analyzed using a generalized linear model with a random subject effect to account for the intrapatient dependence occurring from obtaining multiple evaluations from the same patient. A logit link function was used akin to logistic regression and a compound symmetric correlation structure was assumed.

Results: 68.8% of the cases were hormone receptor-positive, 18.8% HER2-positive, and 27.1% TNBC. The treatments received were 58.4% hormonal therapy, 31.2% chemotherapy, 26.4% included anti-HER2 therapy, 2 cases were on targeted therapy, and 1 case was not on any treatment. Three patients had stage 4 disease in complete remission. ctDNA analysis was repeated on average 4 days prior to radiological evaluation. The average time between repeat assessments was 108.5 days. 93% of the patients had a genomic alteration detected at some point during their course of disease. The most common mutations detected were TP53 41.7%, PIK3CA 35.4%, ESR1 18.8%, and ERBB2 amplifications 6.3%. A dichotomized change in ctDNA is a significant predictor of clinical benefit (p &lt; 0.0001). The intrapatient correlation is estimated to be 0.273 for the transformed variable. The model yields a predicted probability of clinical benefit of 26.9% when the increase in ctDNA is greater than or equal to 0.5 and when the increase in ctDNA is less than 0.5, the a predicted probability of clinical benefit is 78.4%. The concordance of change in ctDNA and change in CA 27-29 was 76.2%.

Conclusions: Serial evaluation of serum ctDNA may be useful to evaluate molecular response to treatment which may correlate with clinical benefit and potentially guide treatment decisions. Early indication that a chosen therapy is not effective may lead to avoidance of overtreatment and initiation of an alternative regimen. Further, prospective studies are needed.

Citation Format: Patel A, Mukherjee A, Hwang D, Ensor J, Patel TA, Chang JC, Rodriguez AA. Serial monitoring of circulating tumor DNA in patients with metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-06.

Correlating mammographic and pathologic findings in clinical decision support using natural language processing and data mining methods

BACKGROUND

A key challenge to mining electronic health records for mammography research is the preponderance of unstructured narrative text, which strikingly limits usable output. The imaging characteristics of breast cancer subtypes have been described previously, but without standardization of parameters for data mining.

METHODS

The authors searched the enterprise-wide data warehouse at the Houston Methodist Hospital, the Methodist Environment for Translational Enhancement and Outcomes Research (METEOR), for patients with Breast Imaging Reporting and Data System (BI-RADS) category 5 mammogram readings performed between January 2006 and May 2015 and an available pathology report. The authors developed natural language processing (NLP) software algorithms to automatically extract mammographic and pathologic findings from free text mammogram and pathology reports. The correlation between mammographic imaging features and breast cancer subtype was analyzed using one-way analysis of variance and the Fisher exact test.

RESULTS

The NLP algorithm was able to obtain key characteristics for 543 patients who met the inclusion criteria. Patients with estrogen receptor-positive tumors were more likely to have spiculated margins (P = .0008), and those with tumors that overexpressed human epidermal growth factor receptor 2 (HER2) were more likely to have heterogeneous and pleomorphic calcifications (P = .0078 and P = .0002, respectively).

CONCLUSIONS

Mammographic imaging characteristics, obtained from an automated text search and the extraction of mammogram reports using NLP techniques, correlated with pathologic breast cancer subtype. The results of the current study validate previously reported trends assessed by manual data collection. Furthermore, NLP provides an automated means with which to scale up data extraction and analysis for clinical decision support. Cancer 2017;114-121. © 2016 American Cancer Society.

Abstract P6-03-05: Cell-free DNA as molecular tool for monitoring disease progression and response to therapy in breast cancer patients

Background: Identification of cancer-specific genes from breast cancer cells was instrumental in the advancement of targeted breast cancer therapy. However, with genomic heterogeneity within the breast cancer and evolution of cancer over time, genomic sequencing obtained from a single biopsy site may not capture the complete genomic profile. Thus, circulating cell-free DNA (cfDNA), isolated from plasma, is potentially a non-invasive source of identifying cancer-specific genomic alterations and may provide comprehensive genomic data throughout a patient's clinical course as they undergo anti-cancer therapy.

Method: We performed a retrospective chart review of 100 patients with stage 4 or high-risk stage 3 breast cancer who were tested for cfDNA genomic alterations. The most common actionable cancer specific genomic alterations were identified. In 23 patients who also had genomic analysis from tumor DNA (tDNA), an analysis using the Cohen's Kappa statistic was performed to determine the degree of agreement between genomic alterations found in tDNA and cfDNA. The proportion of patients with clinical disease progression between two cohorts determined by change in mutant allele frequency was compared using two-sided Fisher's exact test. Patients who received targeted therapy based on the identified genomic alteration were followed to determine response to therapy.

Results: In cfDNA of 100 breast cancer patients, the most commonly found cancer specific genomic alterations were TP53, PIK3CA, EGFR amplification, and ERBB2 amplification, with incidence rates 27%, 22%, 9%, and 7%, respectively. In tDNA of 23 patients, incidence rates were 65%, 26%, 9%, and 13%. PIK3CA and ERBB2 amplification demonstrated robust agreement between tDNA and cfDNA (Cohen's Kappa= 0.64 and 0.77, respectively). TP53 and EGFR amplification demonstrated poor agreement between tDNA and cfDNA (Cohen's Kappa= 0.18 and 0.33, respectively). There were 22 patients who had baseline and post-therapy mutant allele frequency measurements of TP53 and PIK3CA. Directional change of mutant allele frequency was closely associated with patient's response to therapy (p=0.0017). 8 out of 8 patients (100%) who had progression of disease had increase in mutant allele frequency. 10 out of 14 patients (71%) of patients who responded to therapy had decrease in mutant allele frequency. 6 patients who were found to have ERBB2 amplification were initiated on anti-HER2 cancer therapy. 5 of 6 patients (83%) had clinical response to therapy, while one patient had progression of disease. 3 patients who were found to have EGFR amplification (2 in cfDNA, 1 in tDNA) were initiated on anti-EGFR therapy. 2 of 3 patients (67%) had clinical response to therapy, while one patient had progression of disease.

Conclusion: There is no definite agreement between genomic alterations found in tDNA and those found in cfDNA. Whether this is due to tumor heterogeneity or tumor evolution over time with administration of anti-cancer treatment remains unknown. However, identification of selected cancer specific genomic alterations from cfDNA may be a non-invasive tool to monitor disease progression and response to breast cancer therapy.

Citation Format: Liang DH, Patel A, Ensor JE, Patel TA, Chang JC, Rodriguez AA. Cell-free DNA as molecular tool for monitoring disease progression and response to therapy in breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-05.

Antitumor activity of Cetuximab in combination with Ixabepilone on triple negative breast cancer stem cells

Background

Developing novel strategies against treatment-resistant triple negative breast cancer (TNBC) cells remains a significant challenge. The ErbB family, including epidermal growth factor receptor (EGFR), plays key roles in metastasis, tumorigenesis, cell proliferation, and drug resistance. Recently, these characteristics have been linked to a small subpopulation of cells classified as cancer stem cells (CSC) which are believed to be responsible for tumor initiation and maintenance. Ixabepilone is a new generation microtubule-stabilizing agent, which has been expected to be more efficacious than conventional taxanes. Here we aim to investigate whether the EGFR monoclonal antibody Cetuximab, in combination with Ixabepilone, is more effective in eliminating CSC populations compared to chemotherapy alone in TNBC.

Methods

Representative TNBC cell lines (MDA-MB-231 and SUM159) were used to evaluate breast CSC populations. We used fluorescence-activated cell sorter analysis (CD44⁺ and CD24^-/low, or Aldefluor⁺) and a self-renewal assay called mammosphere formation efficiency (MSFE) to measure CSC population size after treatment with Cetuximab, or Cetuximab plus Ixabepilone in vitro.

Results

Although there was no significant decrease in cell viability, Cetuximab reduced MSFE and the CSC population in breast cancer cells in vitro and in vivo through inhibition of autophagy. Also, SUM159 and MDA-MB-231 orthotopic tumors demonstrated partial response to Centuximab or Ixabepilone monotherapy; however, the effect of the combination treatment was significant only in SUM159 tumors (p <0.0001), when compared to Ixabepilone alone.

Conclusions

Overall, our findings demonstrate that EGFR-targeted therapy by Cetuximab effectively reduces the CSC population in TNBC tumors. However, combination therapy with Ixabepilone may be effective only in a small subset of TNBCs, warranting further investigation of alternative approaches to target multiple pathways for TNBC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0662-4) contains supplementary material, which is available to authorized users.

Cell-free DNA as a molecular tool for monitoring disease progression and response to therapy in breast cancer patients

Due to the spatial and temporal genomic heterogeneity of breast cancer, genomic sequencing obtained from a single biopsy may not capture the complete genomic profile of tumors. Thus, we propose that cell-free DNA (cfDNA) in plasma may be an alternate source of genomic information to provide comprehensive data throughout a patient's clinical course. We performed a retrospective chart review of 100 patients with stage 4 or high-risk stage 3 breast cancer. The degree of agreement between genomic alterations found in tumor DNA (tDNA) and cfDNA was determined by Cohen's Kappa. Clinical disease progression was compared to mutant allele frequency using a two-sided Fisher's exact test. The presence of mutations and mutant allele frequency was correlated with progression-free survival (PFS) using a Cox proportional hazards model and a log-rank test. The most commonly found genomic alterations were mutations in TP53 and PIK3CA, and amplification of EGFR and ERBB2. PIK3CA mutation and ERBB2 amplification demonstrated robust agreement between tDNA and cfDNA (Cohen's kappa = 0.64 and 0.77, respectively). TP53 mutation and EGFR amplification demonstrated poor agreement between tDNA and cfDNA (Cohen's kappa = 0.18 and 0.33, respectively). The directional changes of TP53 and PIK3CA mutant allele frequency were closely associated with response to therapy (p = 0.002). The presence of TP53 mutation (p = 0.0004) and PIK3CA mutant allele frequency [p = 0.01, HR 1.074 (95 % CI 1.018-1.134)] was excellent predictors of PFS. Identification of selected cancer-specific genomic alterations from cfDNA may be a noninvasive way to monitor disease progression, predict PFS, and offer targeted therapy.

Chloroquine eliminates cancer stem cells through deregulation of Jak2 and DNMT1

Triple negative breast cancer (TNBC) is known to contain a high percentage of CD44(+) /CD24(-/low) cancer stem cells (CSCs), corresponding with a poor prognosis despite systemic chemotherapy. Chloroquine (CQ), an antimalarial drug, is a lysotropic reagent which inhibits autophagy. CQ was identified as a potential CSC inhibitor through in silico gene expression signature analysis of the CD44(+) /CD24(-/low) CSC population. Autophagy plays a critical role in adaptation to stress conditions in cancer cells, and is related with drug resistance and CSC maintenance. Thus, the objectives of this study were to examine the potential enhanced efficacy arising from addition of CQ to standard chemotherapy (paclitaxel) in TNBC and to identify the mechanism by which CQ eliminates CSCs in TNBCs. Herein, we report that CQ sensitizes TNBC cells to paclitaxel through inhibition of autophagy and reduces the CD44(+) /CD24(-/low) CSC population in both preclinical and clinical settings. Also, we are the first to report a mechanism by which CQ regulates the CSCs in TNBC through inhibition of the Janus-activated kinase 2 (Jak2)-signal transducer and activator of transcription 3 signaling pathway by reducing the expression of Jak2 and DNA methyltransferase 1.

Inhibition of iNOS as a novel effective targeted therapy against triple-negative breast cancer

Introduction

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer with no effective targeted therapy. Inducible nitric oxide synthase (iNOS) is associated with poor survival in patients with breast cancer by increasing tumor aggressiveness. This work aimed to investigate the potential of iNOS inhibitors as a targeted therapy for TNBC. We hypothesized that inhibition of endogenous iNOS would decrease TNBC aggressiveness by reducing tumor initiation and metastasis through modulation of epithelial-mesenchymal transition (EMT)-inducing factors.

Methods

iNOS protein levels were determined in 83 human TNBC tissues and correlated with clinical outcome. Proliferation, mammosphere-forming efficiency, migration, and EMT transcription factors were assessed in vitro after iNOS inhibition. Endogenous iNOS targeting was evaluated as a potential therapy in TNBC mouse models.

Results

High endogenous iNOS expression was associated with worse prognosis in patients with TNBC by gene expression as well as immunohistochemical analysis. Selective iNOS (1400 W) and pan-NOS (L-NMMA and L-NAME) inhibitors diminished cell proliferation, cancer stem cell self-renewal, and cell migration in vitro, together with inhibition of EMT transcription factors (Snail, Slug, Twist1, and Zeb1). Impairment of hypoxia-inducible factor 1α, endoplasmic reticulum stress (IRE1α/XBP1), and the crosstalk between activating transcription factor 3/activating transcription factor 4 and transforming growth factor β was observed. iNOS inhibition significantly reduced tumor growth, the number of lung metastases, tumor initiation, and self-renewal.

Conclusions

Considering the effectiveness of L-NMMA in decreasing tumor growth and enhancing survival rate in TNBC, we propose a targeted therapeutic clinical trial by re-purposing the pan-NOS inhibitor L-NMMA, which has been extensively investigated for cardiogenic shock as an anti-cancer therapeutic.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0527-x) contains supplementary material, which is available to authorized users.

Erratum to: Dual HER2 blockade: preclinical and clinical data

No abstract.

Field- and temperature-dependent 13C NMR studies of the EDTA-Zn2+ complex: insight into structure and dynamics via relaxation measurements

The relaxation rates for the three different carbon types in EDTA (carbonyl, CH2 central, and CH2 lateral) were measured with and without Zn(2+) as a function of field strength and temperature. The use of different field strengths in combination with NOE measurements allowed for the contribution of each relaxation mechanism (chemical shift anisotropy; spin rotation; dipole-dipole) to the total relaxation rate for each carbon to be determined. Temperature studies allowed for determination of the activation energy (Ea) for the motions of each carbon type. The most surprising result was the observation that the τ(c) decreases significantly for the lateral carbon upon addition of Zn(2+) at neutral pH, going from 54 to 8.6 ps at 298 K. This appears to be a pH-dependent phenomenon as other reports indicate that τ(c) increases for the lateral carbon upon addition of Zn(2+) under strongly basic conditions.

Dual HER2 blockade: preclinical and clinical data

The estrogen receptor and human epidermal growth factor receptor (HER) signaling pathways are the dominant drivers of cell proliferation and survival in the majority of human breast cancers. Not surprisingly, targeting these pathways provides the most effective therapies in appropriately selected patients. However, de novo and acquired resistance remain major obstacles to successful treatment. By increasing the understanding of the molecular mechanisms of combined HER2-targeted therapies, we aim to be better able to select patients who would respond to these treatments and understand some of the mechanisms of resistance to HER2-targeted treatments. Recent studies have demonstrated an increased effectiveness of dual targeted HER2 therapies against HER2-amplified breast cancer as compared with single blockade. These studies have resulted in the recent US Food and Drug Administration approval of the combination of taxane chemotherapy with pertuzumab and trastuzumab in the first-line metastatic setting as well as an accelerated approval in the neoadjuvant setting. Another mechanism for overcoming resistance to HER2 targeted therapies is the antibody-drug conjugate trastuzumab-emtansine, which targets the HER2 receptor conjugated to the potent antimicrotubule agent mertansine, allowing for intracellular release of the cytotoxic drug. Studies evaluating the efficacy of dual blockade with antibody-drug conjugate are currently ongoing. This article reviews recent data on different combinations of anti-HER2 treatments as well as ongoing and future research in this area.

Abstract P2-16-23: The ENCHANT-1 trial (NCT01677455): An open label multicenter phase 2 proof of concept study evaluating first line ganetespib monotherapy in women with metastatic HER2 positive or triple negative breast cancer (TNBC)

Background: Hsp90 is a molecular chaperone protein required for the stabilization and activation of many proteins, referred to as Hsp90 ‘clients’, such as HER2, HIF1-a, EGFR, ER, PI3K, AKT, P53 and VEGFR. The drug candidate, ganetespib is a novel triazolone inhibitor of Hsp90, with over 700 patients treated to date. Ganetespib has shown activity in preclinical models of HER2+, ER+/PR+ and TNBC. Early clinical trials documented ganetespib single agent activity in heavily pretreated HER2+ and TNBC patients. Ganetespib has been well tolerated in clinical trials with a favorable safety profile. This efficacy-screening study is designed to provide further evidence of ganetespib activity and identify potentially predictive biomarkers in metastatic breast cancer (BC).

Methods: The ENCHANT-1 Trial is an international, first-line 2-cohort Phase 2 study in BC patients: Cohort A, HER2 amplified (n = 35), and Cohort B, TNBC (n = 35). Patients who present with previously untreated metastatic disease are eligible for treatment with ganetespib at 150 mg/m2 twice weekly on 3 out of 4 wks, for a total of up to 12 wks. Primary endpoint: ORR assessed using RECIST1.1 criteria. Key secondary endpoints include metabolic response as assessed by PET/CT at wk 3 utilizing modified EORTC criteria. Disease progression (PD) at wk 3 by PET imaging indicates discontinuation of study therapy, and is performed to quickly offer patients with metabolic PD a standard of care treatment.

The study is designed as Simon 2-stage requiring at least one OR in 15 patients for the respective cohort to expand to 35 patients. A Steering Committee is established to oversee the overall study and review the interim results.

Results: The study was initiated in 23 centers globally. At the time of submission, a total of 17 patients had been enrolled; TNBC (n = 15) and HER2 (n = 2). Here we report the interim analysis in the TNBC cohort. The median age was 54 years (range 30 -77) with ECOG PS 0 (n = 7/15). Most patients (n = 9) presented with de novo metastatic disease. 5 patients were not evaluable for PET assessment (3 had not yet reached wk 3 and 2 withdrawn before wk 3 for clinical progression), and 9 patients were not evaluable for objective response at wk 6 (3 withdrawn before or at wk 3 for clinical progression and 6 had not yet reached wk 6 evaluation). In the 10 patients with evaluable PET imaging, 9 patients achieved metabolic (m) response (2 mPR, 4 mSD with dominant tumor shrinkage and 3 SD) and one patient with mPD. In the 6 patients evaluable for OR at wk 6, one patient achieved PR, 2 SD and 3 PD. Treatment with ganetespib was well tolerated; the most common AEs were mild or moderate diarrhea (8/15, 53%), fatigue (5/15, 33%), decreased appetite (4/15, 27%), insomnia (4/15, 27%), and nausea (4/15, 27%).

Conclusion: Ganetespib single agent was generally well tolerated and showed anti-tumor activity TNBC patients as early as 3 weeks following treatment. PET seems to be a good tool to screen antitumor activity of new agents in early settings rather that in heavily pretreated patients. The TNBC cohort has met the protocol criteria for proceeding to stage 2.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-23.

Multicenter phase II study of neoadjuvant lapatinib and trastuzumab with hormonal therapy and without chemotherapy in patients with human epidermal growth factor receptor 2-overexpressing breast cancer: TBCRC 006

PURPOSE

We previously reported the eradication of human epidermal growth factor receptor 2 (HER2)- amplified human xenografts in mice by inhibition of the HER2 pathway with lapatinib and trastuzumab to block all homo- and heterodimer signaling as well as by blockade of estrogen receptor (ER) when expressed. In this clinical trial, we sought to translate these findings to patients using targeted therapy without chemotherapy.

PATIENTS AND METHOD

Women with stages II to III HER2-positive breast cancers were eligible. They received trastuzumab once per week (4 mg/kg loading, then 2 mg/kg) and lapatinib 1000 mg once per day for 12 weeks. Women with ER-positive tumors also received letrozole (plus a luteinizing hormone-releasing hormone [LHRH] agonist if premenopausal). Pathologic response was assessed by ER status. Biopsies were obtained at baseline, weeks 2 and 8, and time of surgery.

RESULTS

Sixty-six patients were enrolled, and 64 were eligible and evaluable for response. Median tumor size was 6 cm (range, 1.5 to 30 cm). Adverse events were mainly grades 1 to 2 (GI, 63%; skin, 46%). Grade 3 metabolic, GI, and liver (18%; 12 patients) and grade 4 liver toxicities (one patient) were also observed. Overall, in-breast pathologic complete response (pCR; ypT0-is) was 27% (ER positive, 21%; ER negative, 36%). The rate of low-volume residual disease (ypT1a-b) was 22% (ER positive, 33%; ER negative, 4%).

CONCLUSION

In patients with locally advanced HER2-positive breast cancer, our approach of targeted therapy only resulted in a high pCR rate without chemotherapy. Our data support the hypothesis that selected patients with HER2-positive tumors may not need chemotherapy, and more-complete blockade of HER receptors and ER is an effective strategy worthy of further study.

Identification of prognosis-relevant subgroups in patients with chemoresistant triple-negative breast cancer

PURPOSE

Patients with triple-negative breast cancer (TNBC) and residual disease after neoadjuvant chemotherapy generally have worse outcome; however, some patients with residual tumor after neoadjuvant chemotherapy do not relapse. We hypothesize that there are subgroups of patients with chemoresistant TNBC with different prognosis.

EXPERIMENTAL DESIGN

Forty-nine chemoresistant cases from 111 patients with TNBC treated with neoadjuvant chemotherapy (M.D. Anderson Cancer Center, Houston, TX) constituted the discovery cohort, and 25 chemoresistant samples from 47 neoadjuvant chemotherapy-treated TNBC (The Methodist Hospital, Houston, TX) were chosen for validation. Extended validation was carried out in 269 operable TNBC predicted to be chemoresistant by expression pattern from published datasets.

RESULTS

We established a seven-gene prognostic signature using dChip and gene set enrichment analyses. In the independent validation cohort, the classifier predicted correctly with positive predictive value of 75.0% and negative predictive value (i.e., relapse-free survival; RFS) of 76.9% at 3 years. Those predicted to relapse had a HR of 4.67 [95% confidence interval (CI): 1.27-17.15] for relapse in 3 years. In extended validation, patients predicted not to relapse exhibited 3-year RFS of 78.9%, whereas the 3-year RFS was 48.5% for patients predicted to relapse, with HR of 2.61 (95% CI: 1.52-4.49). The TNBC subgroup that predicted to have relatively favorable prognosis was characterized by high expression of "luminal-like" genes [androgen-receptor (AR) and GATA3], whereas the subgroup with worse prognosis was characterized by expression of cancer stem-cell markers.

CONCLUSION

We developed a clinically relevant signature for patients with chemoresistant TNBC. For these women, new therapeutic strategies like targeting AR activation or cancer stem cells may need to be developed.

Abstract P5-03-03: Antitumor Activity and Cancer Stem Cells Effect of Cetuximab in Combination with Ixabepilone in Triple Negative Breast Cancers (TNBC)

Purpose: The ErbB family, including EGFR, has been demonstrated to play key roles in metastasis, tumorigenesis, cell proliferation, and drug resistance. Recently, these characteristics have been linked to a small subpopulation of cells classified as cancer stem cells (CSCs) which are believed to be responsible for tumor initiation and maintenance. Ixabepilone is the microtubule-stabilizing agent has been expected to be more sensitive than the conventional taxanes. The aim of this study was to investigate whether the EGFR monoclonocal antibody cetuximab, in combination with ixabepilone is a more effective treatment, and kill cancer stem cells more effectively as compared to chemotherapy alone in TNBC.

Experimental Design and Results: Breast CSC populations were evaluated with FACS analysis (CD44+ and CD24−/low, or Aldefluor+) and mammosphere formation efficiency (MSFE). In vitro, we demonstrated that in triple negative cell lines (MDA-MB-231 and SUM159), cancer stem cell populations were decreased after treatment of cetuximab, or cetuximab plus ixabepilone. In vivo, cetuximab in combination with ixabepilone treatment caused significant tumor regression (cetuximab vs. cetuximab+ ixabepilone; tumor volume fold change P &lt;0.05 (MDA-MB-231), P &lt;0.0001 (SUM159) in triple negative breast cancer xenografts. Thus, cetuximab decreased CSC population in xenograft tumors. Decrease in autophagy (LC3b, p62 and autophagosomes) were seen in cetuximab-treated tumors.

Conclusions: These studies demonstrate that cetuximab in combination with ixabepilone is more effective than chemotherapy alone in TNBC by affecting CSCs, as well as bulk tumor. These data support a neoadjuvant phase II study comparing ixabepilone vs. ixabepilone +cetuximab in TNBC patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-03.

Abstract P6-07-11: Is the prognosis of lymphotropic invasive micropapillary carcinoma worse than invasive ductal carcinoma?: A population-based study of 645 patients

Purpose: Invasive micropapillary carcinoma (IMPC) is an uncommon distinct variant of breast carcinoma and is associated with an increased risk for regional lymph node metastases. Therefore, IMPC is considered to have an unfavorable prognosis when compared to invasive ductal carcinoma (IDC). The prognostic factors for IMPC are not well characterized due to the relative scarcity of cases reported in the literature.

Methods: We analyzed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database to evaluate prognostic factors of a population of 645 breast IMPC patients and 300,060 breast IDC patients reported between 2001 and 2008. Using univariate and multivariate analyses, hazard ratios (HR) were calculated for disease-specific (DSS) and overall survival (OS) for these patients using parameters such as patient age at diagnosis, histological grade, ER status, PR status, tumor size, and degree of lymph node positivity. Subset analysis of high grade, lymph node-positive patients was performed to compare DSS and OS between IMPC and IDC.

Results: The 5-year DSS and OS for IMPC patients were 92.1% and 84.6% compared to 5-year DSS and OS of 88.5% and 80.2% for IDC patients. At presentation, TNM staging of IMPC cases was similar to IDC except for a higher percentage of LN metastases (52.4% in IMPC vs. 34.7% in IDC). Of those with known estrogen receptor (ER) status, 84.2% of IMPC cases were ER-positive, which was associated with better DSS (Hazard Ratio (HR) 0.36, p &lt; 0.002) and OS (HR 0.62, p = 0.072). Patients with four or more positive lymph nodes had worse DSS (HR 7.1, p &lt; 0.0001) and OS (HR 3.2, p &lt; 0.0001) than node-negative patients, but those with one to three positive lymph nodes had similar DSS (HR 1.04, p = 0.96) and OS (HR 0.99, p = 0.97) as node-negative patients. In the subset of patients with high grade, node-positive breast carcinoma, patients with micropapillary histology had better DSS (p &lt; 0.03) and a trend towards better OS (p = 0.12) than high grade, node-positive invasive ductal carcinoma. This subset of IMPC patients also had a higher percentage of ER-positive tumors (77%) compared to IDC patients (56%).

Conclusions: While IMPC has a high propensity for lymph node metastasis, it has a disease-specific and overall prognosis that compares favorably to IDC. The higher percentage of hormone-receptor positivity may account for this survival advantage, even in high grade, node-positive disease. Therefore, estrogen-receptor-negativity or having four or more positive lymph nodes at presentation may potentially serve as prognostic markers for IMPC patients. In this study population, patients with one to three positive lymph nodes have DSS and OS similar to node-negative patients. Additional clinical studies are warranted to further investigate this observation. This is the largest study of IMPC to date, and these findings help our understanding of this uncommon histological variant of breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-11.

Abstract P3-06-14: Identification of Prognosis-Relevant Subgroups in Patients with Chemoresistant Triple Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. TNBC patients with pathologic complete response (pCR) have excellent survival, but those with residual disease after neoadjuvant chemotherapy have significantly worse outcome. However, some patients having extensive residual cancer burden after neoadjuvant chemotherapy do not relapse, and we hypothesize that there may be subgroups with diverse prognosis among these chemoresistant TNBC patients.

Methods: Forty-nine cases with residual cancer from 111 TNBC patients treated with neoadjuvant chemotherapy (in M.D. Anderson Cancer Center, 2000–2006) constituted the discovery cohort. Twenty-five chemoresistant samples from 47 neoadjuvant chemotherapy-treated TNBC (in Baylor College of Medicine and Methodist Hospital, 2002–2006) were chosen for validation. Extended validation was performed in 269 operable TNBC predicted to be chemoresistant (using a JAMA-published genomic predictor) from public databases.

Results: By comparing the gene expression data from cases in relapse with those from un-relapsed cases, we established a 7-gene prognostic signature (including AR, ESR2, GATA3, GBX2, KRT16, MMP28, and WNT11) using dChip and gene enrichment analyses. In the discovery cohort, the signature showed positive predictive value (PPV; i.e., cumulative relapse rate of patients predicted to relapse in 3 years) of 95.4% and negative predictive values (NPV; i.e., relapse-free survival of patients predicted not to relapse in 3 years) of 100%. In the validation cohort, the classifier predicted correctly with PPV of 75.0% and NPV of 76.9% at 3 years. Compared with patients predicted not to relapse, those predicted to relapse had a hazard ratio of 3.37 (95% CI, 1.15–9.85) for disease recurrence or death in 3 years. In an extended validation cohort of 269 patients, our signature discriminated chemoresistant TNBC in overall cohort (PPV, 52.4%; NPV, 77.7%; log rank P &lt; 0.0001), or each subset (e.g., log rank p = 0.001 for Rotterdam set; p = 0.013 for Frankfurt set), with adjusted overall hazard ratio of 2.07 (95% CI, 1.26–3.39). This signature was the only marker that could effectively predict the relapse in patients with chemoresistant TNBC. Of note, the subgroup predicted not to relapse was characterized by high expression of luminal-like genes (AR, GATA3), while the subgroup predicted to have high possibility of relapse was characterized by high expression of cancer stem cell and epithelial-to-mesenchymal transition associated genes (WNT11, MMP28). The former corresponded to the luminal AR subtype and the latter to the mesenchymal stem-like subtype, according to Pietenpol's TNBC subtype classification.

Conclusion: We developed a clinically useful prognostic signature for chemoresistant TNBC. For these chemoresistant TNBC patients, new therapeutic strategies targeting AR-activation or cancer stem cells need to be developed.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-14.

P3-14-09: A Phase II Preoperative Study of Dasatinib, a Multi-Targeted Tyrosine Kinase Inhibitor, in Locally Advanced “Triple-Negative” Breast Cancer Patients

Background: We previously reported that kinases (Src, Yes-1, cKIT, Abl, and EPH4) were druggable in triple negative breast cancer (TNBC). In this clinical trial, we sought to translate these findings by treating TNBC patients with dasatinib, a multi-targeted kinase inhibitor against these targets.

Methods: Women with stage II-III TNBC were eligible. Patients received dasatinib at 100 mg daily for 3 to 4 weeks before standard-of-care definitive surgery and chemotherapy. Biopsies were performed at baseline, week 1, and at the time of surgery. A cohort of patients had positron emission mammography (PEM; baseline and at 2–3 weeks of dasatinib therapy). This study was designed to detect an increase in clinical response rate from 10% to 25%, using a Simon optimal two stage design, with one-sided alpha=5% and power=80%. At least 3 responses out of 22 patients were needed to proceed to the second stage.

Results: 22 patients were enrolled (Table 1). Median tumor size was 7.0 cm (range 2.4-25 cm). Adverse events were modest, mainly grade 1–2 (headache: 45%, abnormal LFTs: 55%, GI: 23%, fatigue: 18%). One patient had a myocardial infarction 24 hours after starting dasatinib. Out of 22 patients, 2 (9%) had a clinical partial response after 3–4 weeks of therapy, 15 had stable disease (68%), while 5 had progressive disease (23%). Of the 8 patients who received paired PEM imaging, metabolic responses were observed in 2 patients (25%). Conclusion: A short course of dasatinib led to clinical responses in 2 out of 22 patients with TNBC, and the study did not proceed to second stage. Since TNBC is a heterogeneous disease, biomarker studies including sequencing of candidate genes like B-RAF for inactivating mutations might enable selection of those TNBC patients who could benefit from dasatinib.

Characterizing cancer cells with cancer stem cell-like features in 293T human embryonic kidney cells

BACKGROUND

Since the first suggestion of prospectively identifiable cancer stem cells in solid tumors, efforts have been made to characterize reported cancer stem cell surrogates in existing cancer cell lines, and cell lines rich with these surrogates have been used to screen for cancer stem cell targeted agents. Although 293T cells were derived from human embryonic kidney, transplantation of these cells into the mammary fat pad yields aggressive tumors that self-renew as evidenced by serial xenograft passages through transplantation. Herein we fully characterize cancer stem cell-like features in 293T human embryonic kidney cells.

RESULTS

293T cells can be readily cultured and passaged as spheres in serum-free stem cell promoting culture conditions. Cells cultured in vitro as three-dimensional spheres (3D) were shown to contain higher ALDH1 and CD44+/CD24- population compared to monolayer cells. These cells were also resistant to radiation and upregulate stem cell survival signaling including beta-catenin, Notch1 and Survivin in response to radiation. Moreover, 3D spheres generated from the 293T cells have increased expression of mesenchymal genes including vimentin, n-cadherin, zeb1, snail and slug as well as pro-metastatic genes RhoC, Tenascin C and MTA1. In addition, microRNAs implicated in self-renewal and metastases were markedly reduced in 3D spheres.

CONCLUSIONS

293T cells exhibit a cancer stem cell-like phenotype when cultured as 3D spheres and represent an important research tool for studying the molecular and biological mechanisms of cancer stem cells and for testing and developing novel targets for cancer therapy.

BRCA1 gene expression signature predicts for anthracycline-chemosensitivity in triple-negative breast cancer

Abstract #6039

Background: We used a previously published gene expression signature that can identify tumors from BRCA1 mutation carriers to evaluate its predictive value in triple-negative breast cancer as a marker for chemosensitivity to anthracycline-based chemotherapy. We proposed that based on preclinical evidence suggesting that BRCA1-deficient breast cancer cells are sensitive to DNA damaging drugs such as cisplatin and anthracyclines this gene expression profile may identify tumors with anthracycline chemosensitivity. Two previously published studies defined a gene expression signature associated with BRCA1 germline mutation.(1,2) In these studies, sporadic tumors were misclassified as BRCA1 tumors and further analysis revealed methylation of the BRCA1 promoter region and decreased BRCA1 gene expression. This finding suggests the possibility of identifying sporadic tumors with decreased BRCA1 activity.&#x2028; Methods: We selected from our database of a locally advanced breast cancer neoadjuvant trial all cases of triple negative breast cancer that received 4 cycles of doxorubicin/cyclophosphamide(AC, 60/200 mg/m2, every 3 weeks) prior to surgery. Pathologic response to chemotherapy was disappearance of all invasive cancer or microscopic residual disease. Tumoral gene expression profile previously obtained using Affymetrix U133A Chip was analyzed for an optimal set of 100 most differentially expressed genes distinguishing BRCA1 and sporadic triple negative tumors according to the previously identified gene signature by van't Veer et al.1 We performed unsupervised clustering to determine if this signature could classify a subtype of triple-negative tumors with "BRCAness" and to test our hypothesis that BRCA1-like tumors are more sensitive to AC. We then performed a supervised analysis to determine the most differentially expressed genes that could prospectively identify triple-negative sporadic tumors with “BRCAness” and tumors from BRCA1 germline carriers that are sensitive to anthracyclines.&#x2028; Results: Of the 66 patients enrolled in our neoadjuvant trial, 12 patient's tumors were triple negative and received preoperative AC. By unsupervised clustering, the gene expression pattern associated with BRCA1 cancers subdivided these sporadic cancers in to two groups: Group A(6/7 pathologic responders), and group B(5/5 non-pathologic responders). By supervised analysis, the most differentially overexpressed gene from the BRCA1 profile for AC sensitivity was YWHAH(14-3-3 eta polypeptide), while DKK3(Inhibitor of Wnt and Notch signaling pathway) and RPL23A were most overexpressed in all cases with adriamycin-resistance(p&lt;0.01).&#x2028; Discussion: Triple negative sporadic breast cancer displaying “BRCAness” appear to be sensitive to AC chemotherapy. YWHAH, DKK3, and RPL23A are differentially expressed in anthracycline-sensitive versus resistant tumors. These three genes can potentially identify triple-negative breast cancers that exhibit “BRCAness” and sensitivity to DNA-damaging chemotherapy such as cisplatin, anthracycline, or PARP inhibitors.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6039.

Comparison of and Investigation into the Size Effects on the Rotational Dynamics of Two Spherical Molecules: CCl4 and C60

13C spin-lattice relaxation measurements were performed on CCl4 and C60, two spherical molecules, to investigate the role of molecular size on reorientational dynamics. Measurements were taken at common temperatures and in a common environment; deuterated chlorobenzene-d5. Our data indicate that both CCl4 and C6) reorient in the small-step diffusion limit. Correlation times for CCl4 were found to be smaller in CBZ than in the neat and much shorter than predicted by viscosity arguments. We have attributed the higher rotational freedom to higher "free volume" or lower solute-solvent contact probability, in CBZ than in the neat. Experimental tau C values for CCl4 and C60 in CBZ were found to be much different than those predicted by hydrodynamics. Pure inertia differences did not explain the disparities in the correlation times. However, a very reasonable explanation for our experimental findings was found by considering the solvent-to-probe molecular volume ratio and its effect on rotational diffusion. We applied four hydrodynamic-based theories to our data and found that the model by Gierer-Wirtz best duplicated our experimental observations. The success of this model suggests that the relative size of solute and solvent molecules, as well as events at the microscopic level, rather than bulk properties, are excellent descriptors of the factors affecting rotational diffusion.

Monoclonal antibody DS6 detects a tumor-associated sialoglycotope expressed on human serous ovarian carcinomas

A newly developed murine monoclonal antibody, DS6, immunohistochemically reacts with an antigen, CA6, that is expressed by human serous ovarian carcinomas but not by normal ovarian surface epithelium or mesothelium. CA6 has a limited distribution in normal adult tissues and is most characteristically detected in fallopian tube epithelium, inner urothelium and type 2 pneumocytes. Pre-treatment of tissue sections with either periodic acid or neuraminidase from Vibrio cholerae abolishes immunoreactivity with DS6, indicating that CA6 is a neuraminidase-sensitive and periodic acid-sensitive sialic acid glycoconjugate ("sialoglycotope"). SDS-PAGE of OVCAR5 cell lysates has revealed that the CA6 epitope is expressed on an 80 kDa non-disulfide-linked glycoprotein containing N-linked oligosaccharides. Two-dimensional non-equilibrium pH gradient gel electrophoresis indicates an isoelectric point of approximately 6.2 to 6.5. Comparison of the immunohistochemical distribution of CA6 in human serous ovarian adenocarcinomas has revealed similarities to that of CA125; however, distinct differences and some complementarity of antigen expression were revealed by double-label, 2-color immunohistochemical studies. The DS6-detected CA6 antigen appears to be distinct from other well-characterized tumor-associated antigens, including MUC1, CA125 and the histo-blood group-related antigens sLea, sLex and sTn.

Management of recurrent carotid stenosis: should asymptomatic lesions be treated surgically?

PURPOSE

The purpose of this study was to determine factors that may influence patient selection for surgery in recurrent carotid stenosis (RCS) and to contrast the results of primary and secondary carotid endarterectomy (CENDX) with regard to operative morbidity and stroke prevention.

METHODS

Forty-eight patients who underwent CENDX for RCS (RCS-OP group) were compared with a contemporaneous group of 40 patients who on at least one post-CENDX duplex ultrasonography study had a greater than 50% stenosis but did not undergo operation (RCS-NO-OP group). This latter group was drawn from 1053 follow-up duplex studies in 348 patients who underwent primary CENDX between the years 1983 and 1993. Each of these two groups was compared with a metanalysis of six key series derived from the literature.

RESULTS

No significant differences were seen in the demographics or the incidence of risk factors between the two groups except for a higher incidence of coronary artery disease (p < 0.03) and peripheral vascular disease (p < 0.001) in the RCS-OP group. The operation-specific stroke rate was 2.1%, and the 30-day mortality was also 2.1%. Symptomatic RCS was the indication in 56% of cases. Important anatomic differences were found between groups. The duplex/arteriographic degree of stenosis was greater than 90% in 75% of the patients in the RCS-OP group, whereas only 10% of the patients in the RCS-NO-OP group had greater than 80% stenosis, most being in the 50% to 80% range. An unexpected finding was the sudden progression to occlusion in 10 (25%) of 40 in the RCS-NO-OP group, with 2 (5%) of 10 of the occlusions presenting as unheralded strokes. Overall, a stroke without an antecedent transient ischemic attack occurred in 3 (7.5%) of 40 of patients in the RCS-NO-OP group, all in patients with greater than 75% stenosis on their last documented scan preceding the stroke.

CONCLUSION

Given the relatively low stroke rate with surgery in the RCS-OP group (2.1%) and the higher incidence of unheralded strokes (7.5%) in the RCS-NO-OP group, a more aggressive approach may be warranted in patients with asymptomatic high-grade (> 75%) RCS, a strategy not unlike that adopted for primary CENDX.

Duplex-derived valve closure times fail to correlate with reflux flow volumes in patients with chronic venous insufficiency

The best way to quantitate venous reflux is still a matter of debate. Duplex-derived valve closure time (VCTs) have been used recently because they can be measured easily. We examined the relationships between VCT and duplex-obtained quantitation of venous volume and between VCT and air plethysmography (APG). Sixty-nine legs in 45 patients with varying clinical degrees of chronic venous insufficiency were studied by duplex scan and APG. VCTs were compared with duplex-derived flow calculations and with APG-derived venous filling index and residual volume fraction. The patient's mean age was 47.5 +/- 13.9 years; the mean duration of their symptoms was 13 +/- 4 years. Twenty percent had a history of deep venous thrombosis, and 29% had undergone venous surgery. No correlation was found between VCT and flow volume or between VCT and flow at peak reflux at any of the anatomic locations studied: saphenofemoral junction, greater saphenous vein, lesser saphenous vein, superficial femoral vein, profunda femoris vein, and popliteal vein. Likewise, no correlation was found between total VCT and APG-derived venous filling index or between total flow volumes and APG-derived residual volume fraction. Total VCT and total flow volumes did, however, have a moderate correlation (r = 0.65; p = 0.0003). Duplex-derived VCTs, although extremely useful in determining the presence of reflux, do not correlate with the magnitude of reflux, and should not be used to quantitate the degree of reflux.

Comparison of skeletal muscle laser Doppler flowmetry to changes in central hemodynamics in detecting the physiological response to moderate hemorrhage

Previous studies have demonstrated that laser Doppler (LD) flowmetry is a useful technique for following changes in blood flow in a tissue bed, but the potential role of LD flowmetry in management of the critically ill patient is unclear. This study sought to establish the sensitivity of LD flowmetry compared to changes in centrally measured hemodynamic parameters in response to a mild hemorrhagic episode. In order to establish the correlation between LD flow and actual blood flow, livers from Sprague-Dawley rats were isolated and perfused via the portal vein with citrate anti-coagulated rat blood. Changes in LD flow were recorded while changing blood flow via the perfusion pump. There was a strong correlation between pump flow and LD flow (for N = 5 livers, r > 0.9; P < 0.05). This relationship was stable at hematocrits > 20. The second part of this study tested the sensitivity of LD flowmetry in anesthesized baboons. An LD probe was placed on the surface of the gracilis muscle of the adult male baboons. LD flow and hemodynamic parameters were measured following two episodes of bleeding and reinfusing 250 cc of blood. During the first bleed there were significant changes in heart rate (97 + 8 to 159 + 12), mean arterial pressure (125 + 6 to 105 + 9), and LD flow (20.6 + 4.6 to 11.9 + 3.6); these parameters returned to normal after reinfusion of blood. During the second bleed, the only parameters that showed significant changes were heart rate (118 + 5 to 135 + 12) and LD flow (17.5 + 8 to 10.7 + 3.4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenomyosis as seen on blood flow and blood pool imaging during bone scintigraphy

A 42-year-old woman presented with intermittent low back and left lower extremity pain. The blood flow and blood pool images of bone scintigraphy showed a large focus of increased activity in the right lower abdomen. Computed tomography showed an enlarged uterus displaced to the right side of the pelvis. At surgery, the uterus was found to be involved with adenomyosis. Three-phase bone scintigraphy consisting of blood flow and blood pool images over the anterior pelvis may be a valuable diagnostic aid in the evaluation of lower back or pelvic pain of a woman.

Reliability determination of F mean response latency

Two hundred consecutive ulnar F wave latencies were evaluated in 30 healthy controls (C) and in 9 patients with mild neuropathy (N). The primary study objective was to determine the F wave sample size required to obtain a reliable F mean latency. A secondary objective was to explore the diagnostic utility of three F wave parameters: the minimal F wave latency (Fmin), the average F wave latency (Fmean), and the minimal-maximal F wave latency difference (Frange). For the control group, the Fmean reliability estimates as measured by intraclass correlation coefficients were 0.87, 0.97, and 0.99 with 1, 5, and 10 responses, respectively; for the N group, the corresponding values were 0.73, 0.93, and 0.96. Fmean was abnormal in 89% of the subjects with mild neuropathy whereas Frange and Fmin were abnormal in 67% and 33%, respectively. The study suggests (1) a reliable F mean latency can be obtained by averaging ten F responses; and (2) Fmean and Frange offers promise in increasing the diagnostic utility of the F response in identifying mild neuropathies.

A prospective, randomized trial of Unna's boot versus Duoderm CGF hydroactive dressing plus compression in the management of venous leg ulcers

Leg ulcers caused by chronic venous insufficiency plague an estimated 500,000 Americans, but there have been few improvements in conservative treatment in this century, and Unna's boot continues to be a mainstay of therapy. A recent report suggests that Duoderm CGF dressing provides greater patient comfort and enhanced compliance, but Duoderm alone (without compression) resulted in slower healing compared with Unna's boot. We enrolled 30 patients (30 ulcers) in a clinical trial to compare Duoderm CGF plus compression (Coban wrap) to Unna's boot. No significant difference was observed between the two groups with respect to age, sex, initial ulcer area, ulcer duration, or extent of venous insufficiency by duplex scan. Eight of 16 ulcers (50%) in the Duoderm group healed completely versus 6 of 14 ulcers (43%) in the Unna's boot group (p = 0.18). Healing rates (square centimeters per week) correlated significantly with initial ulcer area and initial ulcer perimeter for both groups but best correlated with initial ulcer perimeter (r = 0.88 with Duoderm, p less than 0.0001; r = 0.80 with Unna's boot, p less than 0.002). After adjusting for differences in initial ulcer perimeter, healing rates were significantly faster for patients on Duoderm than patients on Unna's boot during the first 4 weeks of therapy (0.384 +/- 0.059 cm2/wk/cm perimeter for Duoderm versus 0.135 +/- 0.043 cm2/wk/cm perimeter for Unna's boot; p = 0.002). At 12 weeks patients on Duoderm again appeared to heal faster than those on Unna's boot, although the result did not reach statistical significance (0.049 +/- 0.007 cm2/wk/cm perimeter for Duoderm versus 0.020 +/- 0.017 for Unna's boot, p = 0.11).(ABSTRACT TRUNCATED AT 250 WORDS)

Liver viability after ischemia-reperfusion

Lack of a reproducible model to quantitatively assess hepatocellular injury following ischemia has made it difficult to assess new strategies for minimizing hepatic injury. We studied the progression of hepatocellular injury after ischemia and ischemia with reperfusion in rats. Irreversible injury was quantitated using a triphenyltetrazolium chloride assay that was shown to correlate with ultrastructural changes. Adenosine triphosphate decreased to 36% of basal values after 30 minutes, but returned to normal with reperfusion with no decrease in viability. In contrast, viability fell by 30% after 60 minutes of ischemia, and by 64% when 60 minutes of ischemia was followed by reperfusion. We conclude that reperfusion of ischemic liver increases the degree of irreversible damage. The model employed here seems to be useful for studying ischemic and reperfusion injury in the liver.

Distribution of valvular incompetence in patients with venous stasis ulceration

Valvular incompetence associated with venous ulceration can occur in the superficial, deep, or perforating systems. Duplex imaging was used to evaluate 95 extremities (78 patients) with current venous ulceration to determine the location of incompetence in each extremity. In addition, in 91 of the 95 extremities the area of the venous ulcer was evaluated for the presence of perforating veins or any other superficial veins or both conditions. Sixty-three (66.3%) of the 95 extremities had multisystem incompetence (superficial and perforating plus superficial and deep plus perforating and deep plus superficial and perforating and deep), whereas single system incompetence (superficial plus perforating plus deep) was seen in only 26 (27.3%). Isolated deep incompetence was identified in only two extremities (2.1%). Furthermore, 45% (41/91) of the ulcers had no duplex evidence of any venous abnormality in the ulcer bed. These data show that the site of valvular incompetence occurred in multiple locations, that isolated valvular incompetence of the deep venous system was uncommon, and that perforating veins were not always in the ulcer bed itself. Because standard venous surgery has traditionally been directed toward only one system, this may provide one explanation for ulcer recurrence. Therefore complete venous evaluation with duplex imaging allowing for surgical intervention directed specifically to the sites of involvement in each system is recommended.

Patterns of venous insufficiency in patients with varicose veins

The nature and distribution of venous disease surrounding the development of varicose veins and its treatment is controversial. Using duplex ultrasonography, we evaluated 54 lower extremities in 32 patients with varicose veins who were symptomatic and had obvious varicose veins by clinical examination. Twenty-eight percent had greater saphenous trunk incompetence, 2% had lesser saphenous trunk incompetence, and 96% had branch disease. Deep valvular incompetence was seen in 41%, saphenofemoral junction incompetence in 46%, and incompetence of one or more perforators in 46% of the extremities. Thirty-three percent demonstrated no evidence of associated saphenofemoral junction, deep vein, or perforating vein incompetence, while 20% had concurrent saphenofemoral junction, deep vein, and perforating vein incompetence. These data support the heterogeneity of venous disease seen in patients with varicose veins and suggest that surgical therapy be directed to a patient's specific pattern of incompetence rather than routine saphenofemoral junction ligation or stripping of the greater saphenous trunk.

Correlation of motor units with strength and spectral characteristics in polio survivors and controls

The purpose of this study was to determine whether quantitative motor unit analysis in postpolio individuals correlates with muscle strength, endurance, work capacity, or power spectral characteristics of surface EMG and to determine whether power spectrum differentiates postpolio from control subjects. This study was designed to compare these variables in 34 symptomatic postpolio, 16 asymptomatic postpolio, and 41 control subjects. Quantitative motor unit analysis of the quadriceps femoris muscle was performed using a concentric needle electrode. Isometric knee extension peak torque, endurance (time to exhaustion) at 40% of maximal torque, work capacity (tension time index), and recovery of force through 10 minutes post-exhaustion were determined. Median frequency of the surface power spectrum was determined during the above testing. Power spectrum histograms were compared at the onset and termination of endurance exercise. Motor unit action potential variables did not correlate with isometric peak torque, tension time index, endurance time, recovery of strength, or with median frequency. Surface power spectrum did not differentiate postpolio from control subjects.

Serendipitous finding of transitional cell carcinoma of the kidney on bone and gallium imaging

A 50-year-old woman presented with low back pain. Bone scintigraphy showed a focus of increased activity in the upper pole of the left kidney. Subsequent Ga-67 citrate scintigraphy demonstrated this same abnormal focus as a region of increased activity. Ultrasonography showed a renal mass in the upper pole of the left kidney. At surgery a transitional cell carcinoma of the upper pole of the left kidney was found.

Evaluation of the perforating veins of the lower extremity using high resolution duplex imaging

The purpose of this study was to evaluate duplex imaging as a means of assessing perforating veins in patients with longstanding venous stasis ulceration. Thirty patients with nonhealing venous stasis ulcers and twenty normal volunteers serving as controls were evaluated with a standard 8-MHz imaging probe and integrated pulsed Doppler. The internal diameter of perforating veins was measured and perforators were grouped into one of four categories based on functional criteria: competent perforator with venous flow (C); incompetent perforator with venous flow (IC); competent perforator with arteriovenous flow (C-AVC); incompetent perforator with arteriovenous flow (IC-AVC). Sixteen of the patients with ulcers were subsequently studied by ascending venography and in 11 patients, intraoperative identification of perforating veins was made during the Rob procedure. In this subset of patients the vessel was categorized as competent or incompetent regardless of flow signal. There were significant differences in mean perforator diameter between ulcer patients and normal volunteers. Duplex imaging identified 93 perforators and venography a total of 70. In all 16 extremities, duplex imaging made the diagnosis of significant perforating vein incompetence, verified by venography. Intraoperative findings demonstrated an excellent correlation with duplex imaging. We believe duplex imaging to be a promising new modality for evaluation of the perforating veins of the lower extremity.

The use of internal jugular vein as interposition graft for femoral vein reconstruction following traumatic venous injury: a useful approach in selected cases

Complex venous injuries remain a controversial and interesting challenge to the vascular and trauma surgeon. Data from the Vietnam Vascular Registry, combined with experience from recent civilian series, seem to indicate that the best results are obtained when venous repair is undertaken. This is especially true of combined arterial and venous injury where compromised venous outflow may lead to limb loss in spite of patent arterial reconstruction. The larger size of veins, however, has required the construction of complex and time-consuming panel and spiral-vein grafts. This makes them far from ideal in the trauma treatment setting, where minimization of blood loss and operating room time are high priorities. We present a case of combined injury to both femoral artery and vein, where the femoral vein injury was repaired using autologous internal jugular vein as interposition graft while the arterial injury was repaired with autologous saphenous vein from the opposite limb. The avoidance of prosthetics, ease of harvest, size match, and little associated morbidity all make a strong case for use of the internal jugular vein where speedy reconstruction of large venous conduits is indicated.

Plasma lipid and lipoprotein concentrations in symptomatic postpolio patients

This study reports lipid and lipoprotein concentrations in postpolio patients seen in our postpolio clinic who were evaluated for complaints of progressive weakness, fatigue, and/or pain. Concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were determined after an overnight fast. Sixty-four patients (24 men and 40 women) with a mean age of 48 +/- 10 years were studied. Mean (+/- SD) lipid concentrations (mg/dL) for men and women, respectively, were 220 +/- 46 and 213 +/- 43 for TC; 38.5 +/- 8.6 and 59.1 +/- 18.1 for HDL-C; 148 +/- 46 and 129 +/- 36 for LDL-C; and 205 +/- 107 and 105 +/- 55 for TG. Hyperlipidemia was found in 16 of 24 men and 10 of 40 women. In the men, mean HDL-C concentration was in the lowest decile of our hospital laboratory's reference range, whereas mean TC/HDL-C ratio was elevated above the recommended value. It is suggested that lipid and lipoprotein concentrations be evaluated in postpolio patients because a high prevalence of lipid/lipoprotein disorders was found in our subjects. Further research is needed on this topic.

One-dose technetium-99m pertechnetate imaging in acute testicular torsion followed by manual detorsion

The role of technetium-99m pertechnetate imaging in acute testicular torsion is well appreciated. Manual testicular detorsion under local anesthesia may be performed in the nuclear medicine clinic by the urology service immediately following initial diagnostic scintigraphy. Following manual testicular detorsion, continued images of the testes are obtained up to 30 minutes without having to reinject the patient with technetium-99m pertechnetate. Reperfusion of the affected testicle will be dramatically noted if the manual detorsion is successful. Four cases are presented to illustrate this.

Gallbladder perforation seen on hepatobiliary imaging following morphine sulfate injection

A case of gallbladder perforation imaged during morphine-augmented cholescintigraphy is presented. Tc-99m DISIDA imaging dramatically demonstrated the bile leak. Whether morphine sulfate contributed to the perforation of the gallbladder is debatable.