Abstract P6-01-06: Multi-Parametric MRI-Based Radiomics Models from Tumor and Peritumoral Regions as Potential Predictors of Treatment Response to Neoadjuvant Systemic Therapy in Triple Negative Breast Cancer Patients

PURPOSE Triple negative breast cancer (TNBC) is an aggressive and heterogeneous subtype of breast cancer. Pathologic complete response (pCR) to neoadjuvant systemic therapy (NAST) predicts better survival. Early prediction of the treatment response can potentially triage non-responding patients to alternative protocol treatments, spare them of the unneeded toxicity, and improve pCR. We evaluated the ability of radiomic textural analysis of intratumoral and peritumoral regions on the dynamic contrast enhanced (DCE) and diffusion-weighted imaging (DWI) MRI images obtained early during NAST to predict pCR. MATERIALS AND METHODS This IRB-approved prospective study (NCT02276443) included 182 patients with biopsy proven stage I-III TNBC who had multiparametric MRIs at baseline (BL), post 2 cycles (C2), and post 4 cycles (C4) of NAST before surgery. Tumors and peritumoral regions of 5 mm and 10 mm in thickness were segmented on the 2.5 minutes DCE subtraction images and on the b=800 DWI images. Ten histogram-based first order texture features including mean, minimum, maximum, standard deviation, kurtosis, skewness, 1st, 5th, 95th, and 99th percentile, and 300 radiomic Grey Level Co-occurrence matrix (GLCM) features along with their absolute and relative differences between the 3 imaging time points were extracted from the tumors and from the peritumoral regions with an in-house Matlab toolbox. Treatment response at surgery (pCR vs non-pCR) was documented. The samples were divided into training and testing datasets by a 2:1 ratio. Area under the receiver operating characteristics curve (AUC ROC) was calculated for univariate analysis in predicting pCR. Logistic regression with elastic net regularization was performed for texture feature selection. Parameter optimization was performed by using 5-fold cross-validation based on mean cross-validated AUC in the training set. RESULTS Of 182 TNBC patients, 88 (48%) had pCR and 94 (52%) did not achieve pCR. Eight multivariate models combining radiomic features from both DCE and DWI tumoral and peritumoral regions had AUC > 0.8 (0.807-0.831) with p-value < 0.001 in both training and testing sets. The highest AUC=0.831 was obtained from a model consisting of 15 radiomic features: tumor DWI (5 GLCM features) at C2, peritumoral region on DCE (skewness) at C2, tumor DCE (1st, 5th percentile) at C4, tumor DWI (3 GLCM features) at C4, peritumoral region DWI (1 GLCM feature) at C4, and the relative difference between C4/C2 on DCE (5th, 95th percentile and mean). CONCLUSION Multi-parametric MRI-based radiomics models from the tumor and the peritumoral regions showed high accuracy as potential early predictors of NAST response in TNBC patients.

Citation Format: Rania M. Mohamed, Bikash Panthi, Beatriz Adrada, Rosalind Candelaria, Mary S. Guirguis, Wei Yang, Medine Boge, Miral Patel, Nabil Elshafeey, Sanaz Pashapoor, Zijian Zhou, Jong Bum Son, Ken-Pin Hwang, H. T. Carisa Le-Petross, Jessica Leung, Marion E. Scoggins, Gary J. Whitman, Zhan Xu, Deanna L. Lane, Tanya Moseley, Frances Perez, Jason White, Elizabeth Ravenberg, Alyson Clayborn, Mark Pagel, Huiqin Chen, Jia Sun, Peng Wei, Alastair M. Thompson, Stacy Moulder, Anil Korkut, Lei Huo, Kelly K. Hunt, Jennifer K. Litton, Vicente Valero, Debu Tripathy, Clinton Yam, Jingfei Ma, Gaiane Rauch. Multi-Parametric MRI-Based Radiomics Models from Tumor and Peritumoral Regions as Potential Predictors of Treatment Response to Neoadjuvant Systemic Therapy in Triple Negative Breast Cancer Patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-06.

Abstract P6-01-34: Longitudinal DCE-MRI Radiomic Models for Early Prediction of Response to Neoadjuvant Systemic Therapy (NAST) in Triple Negative Breast Cancer (TNBC) Patients

Background and Purpose Early prediction of neoadjuvant systemic therapy (NAST) response in triple negative breast cancer (TNBC) patients could potentially aid in the selection of alternative therapies and avoid unnecessary toxicity in patients unlikely to achieve pathologic complete response (pCR) with NAST. In this study, we investigated the radiomic features of the peritumoral and the tumoral regions from dynamic contrast enhanced (DCE) MRI acquired at different time points of NAST for early treatment response prediction in TNBC. Methods and Materials This study included 182 biopsy-confirmed stage I-III TNBC patients enrolled in an IRB approved prospective clinical trial (NCT02276433). All patients underwent DCE-MRI on a GE 3T MRI scanner at baseline (BL), after two (C2) and four (C4) cycles of doxorubicin/cyclophosphamide based chemotherapy and before surgery. The peritumoral and the tumoral regions were segmented manually by two fellowship-trained radiologists using early phase (2.5 min) DCE-MRI subtraction images. Ten first order radiomic features, 300 grey-level-co-occurrence matrix (GLCM) features along with their absolute and relative differences (C4/BL, C2/BL, C4/C2) between the 3 imaging time points were extracted from the peritumoral and the tumoral regions. Patients were randomly divided into training and testing sets in a 2:1 ratio. For univariate analysis, area under the receiver operating characteristics curve (AUC ROC) was measured to determine the features most predictive of pCR/non-pCR. Wilcoxon Rank Sum test was used to test the statistical significance of predictive performance. In multivariate analysis, radiomic models were established using logistic regression with elastic net regularization followed by 5-fold cross validation for performance assessment. Results Eighty-eight (48%) patients had pCR (59 training, 29 testing) and 94 (52%) patients had non-pCR (63 training, 31 testing). Twenty-five radiomic features (4 from peritumoral C4, 5 from tumoral C4, 4 from peritumoral C4/BL, 6 from tumoral C4/BL, 2 from peritumoral C4/C2 and 4 from tumoral C4/C2) were statistically significant with AUC ≥ 0.75 in both the training and the testing sets at the univariate analysis. The significant features at C4 had AUCs of 0.75-0.79 for the training set and 0.76-0.81 for the testing set. Changes measured between C4 and BL or C2 showed AUC of 0.76-0.84 in the training and 0.75-0.81 in the testing datasets. Eleven multivariate regression models comprised of radiomic features at BL, C2, C4 and their changes (C4/BL, C4/C2 and C2/BL) showed an AUC of 0.80-0.84 for cross validation and an AUC of 0.80-0.82 for independent testing. Conclusions Radiomic models using longitudinal DCE MRI parameters of peritumoral and tumoral regions during NAST have the potential to predict pCR in TNBC patients undergoing NAST.

Citation Format: Bikash Panthi, Rania M. Mohamed, Beatriz Adrada, Rosalind Candelaria, Mary S. Guirguis, Wei Yang, Medine Boge, Miral Patel, Nabil Elshafeey, Sanaz Pashapoor, Zijian Zhou, Jong Bum Son, Ken-Pin Hwang, H. T. Carisa Le-Petross, Jessica Leung, Marion E. Scoggins, Gary J. Whitman, Zhan Xu, Deanna L. Lane, Tanya Moseley, Frances Perez, Jason White, Elizabeth Ravenberg, Alyson Clayborn, Mark Pagel, Huiqin Chen, Jia Sun, Peng Wei, Alastair M. Thompson, Stacy Moulder, Anil Korkut, Lei Huo, Kelly K. Hunt, Jennifer K. Litton, Vicente Valero, Debu Tripathy, Clinton Yam, Jingfei Ma, Gaiane Rauch. Longitudinal DCE-MRI Radiomic Models for Early Prediction of Response to Neoadjuvant Systemic Therapy (NAST) in Triple Negative Breast Cancer (TNBC) Patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-34.

Abstract HER2-01: HER2-01 Clinical and Molecular Characteristics of HER2-low/zero Early Stage Triple-Negative Breast Cancer

Background: In the metastatic setting, low HER2 expression is associated with clinical benefit from trastuzumab deruxtecan, a HER2-targeting antibody drug conjugates. However, little is known about the biological significance of low HER2 expression in patients with early stage triple-negative breast cancer (TNBC) receiving neoadjuvant therapy (NAT). Methods: Out of 595 patients with stage I-III TNBC enrolled on the prospective ARTEMIS trial (NCT02276443) from 2015-2021, we identified 367 patients with available HER2 immunohistochemistry (IHC) results on pre-NAT tumor tissue (HER2-zero: n=218; HER2-low [IHC 1+, 2+]: n=149). All patients were treated with anthracycline-based NAT. In cases where sufficient pre-NAT tumor tissue were available, additional IHC and/or RNAseq were performed. Differential gene expression (DGE) and pathway analysis were performed using DEseq2. Gene set enrichment analysis (GSEA) was performed using the Hallmark gene sets. Deconvolution analyses were performed using CIBERSORT. We controlled for multiple hypothesis using a false discovery rate (FDR) threshold with the Benjamini-Hochberg method, accepting as significant genes with at least a 2-fold change and < 5% FDR. Results: Table 1 summarizes baseline clinicopathological features of the 367 patients. Compared to HER2-zero tumors, HER2-low tumors were less likely of metaplastic histology (p=0.001), associated with lower Ki67 (p=0.017) and were more likely to be androgen receptor (AR)-positive (p=0.01). There were no significant differences in tumor-infiltrating lymphocytes (TILs) infiltration and PD-L1 expression between HER2-zero and HER2-low tumors. Among the 226 patients with sufficient pre-NAT tissue for RNAseq, DGE analyses demonstrated upregulation of genes involved in fatty acid metabolism (ACSM1) and steroid hormone metabolism (DHRS2, UGT2B28) in HER2-low tumors compared with HER2-zero tumors. Deconvolution analyses revealed no significant differences between predicted proportions of immune cell subpopulations between HER2-low and HER2-zero tumors. Although rates of pCR were not significantly different between patients with HER2-zero (46%) and HER2-low tumors (40%) (p=0.34), non-pCR in patients with HER2-low tumors was associated with increased expression of EREG, which encodes an EGFR ligand, while non-pCR in patients with HER2-zero tumors was associated with downregulation in genes involved in immune response pathways. GSEA further identified the Hallmark allograft rejection (FDR q=0.001), interferon gamma response (FDR q=0.002), and interferon alpha response pathways (FDR q=0.007) as the 3 most significantly downregulated pathways in HER2-zero tumors from patients experiencing a non-pCR relative to HER2-zero tumors from patients experiencing a pCR. Conclusion: In early stage TNBC, low HER2 expression is associated with increased AR expression and upregulation of genes associated with fatty acid and steroid hormone metabolism. Gene expression analyses suggest that drivers of resistance to NAT differ between HER2-low and HER2-zero tumors. Biological differences between HER2-zero and HER2-low tumors exist and may influence future personalized treatment for patients with early stage TNBC.

Citation Format: Clinton Yam, Ziyi Li, Anil Korkut, Wencai Ma, Elisabeth Kong, Holly A. Hill, Hussein Abbas, Sausan Abouharb, Beatriz Adrada, Banu K. Arun, Carlos H. Barcenas, Ajit Bisen, Daniel Booser, Aman Buzdar, Rosalind Candelaria, Junjie Chen, Alyson Clayborn, Senthil Damodaran, Qingqing Ding, Haven Garber, Gabriel N. Hortobagyi, Kelly K. Hunt, Nuhad K. Ibrahim, Adaeze Iheme, Meghan S. Karuturi, Kimberly Koenig, Rachel M. Layman, Jangsoon Lee, Jennifer K. Litton, Melissa Mitchell, Giancarlo Moscol, Jason Mouabbi, Rashmi K. Murthy, Oluchi Oke, Paula Pohlmann, David Ramirez, Elizabeth Ravenberg, Sadia Saleem, Mediget Teshome, Vicente Valero, Jason White, Madison Williams, Wendy Woodward, Chasity Yajima, Naoto T. Ueno, Ken Chen, Gaiane Rauch, Lei Huo, Debu Tripathy. HER2-01 Clinical and Molecular Characteristics of HER2-low/zero Early Stage Triple-Negative Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr HER2-01.

Abstract P1-05-15: DCE-MRI for early prediction of excellent response versus chemoresistance in triple negative breast cancer

PURPOSE Triple-negative breast cancer (TNBC) is a heterogeneous disease with variable response to neoadjuvant therapy (NAT). Pathologic complete response (pCR) has become a prognostic marker for overall and disease-free survival. The aim of this study was to determine if dynamic contrast-enhanced (DCE)-MRI after 2 and/or 4 cycles of NAT can identify patients with a high likelihood of achieving pCR, triaging them to standard of care (SOC), or, when appropriate, to de-escalation trials. Conversely, we aimed to identify chemoresistant tumors that are unlikely to achieve pCR and may benefit from escalated targeted trials.

METHOD AND MATERIALS 309 patients with stage I-III TNBC underwent DCE-MRI (temporal resolution: 9-12 sec) at baseline (BL), 2 cycles (C2), and 4 cycles (C4) of SOC doxorubicin/cyclophosphamide (AC) NAT as part of a prospective IRB-approved study (NCT02276443). Tumor volumes of the index lesion were calculated using 3 axis measurements during the early phase of the DCE-MRI (60s). Percent tumor volume reduction (TVR) between BL, C2, and C4 was calculated. Patients were randomly assigned to a training or a validation cohort in a 1:1 ratio. pCR was assessed at surgery after completion of SOC NAT. Correlation between pCR and TVR was evaluated using ROC analysis.

RESULTS Of 309 TNBC patients, 136 (44%) achieved pCR. Following 2 cycles of NAT, TVR >80% was predictive of pCR (chemosensitivity), while TVR ≤ 55% was predictive of non-pCR (chemoresistance) with PPV 80%, NPV 89%, AUC 0.811 (0.73~0.893, p< 0.0001) in the training cohort, and PPV 82%, NPV 85%, AUC 0.815 (CI:0.736~0.894, p< 0.0001) in the validation cohort. Following 4 cycles of NAT, TVR >90% was predictive of pCR, while TVR ≤80% was predictive of non-pCR with PPV 80%, NPV 84%, AUC 0.827 (0.756~0.898, p< 0.0001) in the training cohort and with PPV 73%, NPV 82%, AUC 0.785 (CI:0.709~0.862, p< 0.001) in the validation cohort. Using this model, the pCR status was correctly classified in 50% of TNBC patients using C2 DCE-MRI in the training cohort, and 54% in the validation cohort. Only 8% were misclassified in the training cohort, and 10% in the validation cohort. Using C4 DCE-MRI, the pCR status of 61% and 57% of TNBC was correctly classified in the validation and the testing cohorts, respectively. 12% were misclassified in the validation cohort, and 21% in the testing cohort.

CONCLUSION DCE-MRI after 2 and 4 cycles of AC-based NAT correctly predicted the pCR status of 54% and 57% of TNBC patients, respectively, as either excellent responders or nonresponders with high AUC 0.811 and 0.827. This may allow patients to be triaged to SOC NAT with option of de-escalation or early targeted therapies for non-responders.

Imaging of Noncalcified Ductal Carcinoma In Situ

Ductal carcinoma in situ (DCIS) is a commonly encountered malignancy, accounting for approximately 20% of new breast cancer diagnoses in the United States. DCIS is characterized by a proliferation of tumor cells within the terminal duct lobular unit with preservation of the basement membrane. Typically nonpalpable and asymptomatic, DCIS is most often detected as calcifications on screening mammography. However, DCIS may also be noncalcified. When compared to calcified DCIS, noncalcified DCIS is more likely to be symptomatic, with patients most often presenting with nipple discharge or a palpable mass. Diagnosing noncalcified DCIS is challenging since it may be occult or subtle on mammography, and ultrasound findings can be nonspecific and may be interpreted as benign fibrocystic changes. In cases with a calcified component of DCIS, the extent of DCIS may be underestimated by mammography because not all involved areas may calcify. Breast magnetic resonance imaging (MRI), although less readily available than mammography and ultrasound, is advantageous in detecting noncalcified DCIS, especially high grade DCIS, which may not develop microcalcifications. MRI relies on abnormal contrast uptake due to tumor vascularity and changes in vessel density and permeability. This pictoral review presents the spectrum of imaging findings of noncalcified DCIS to assist radiologists in accurately detecting and describing its key imaging findings. Utilizing different modalities, we review the differential diagnoses for noncalcified DCIS, show illustrative cases of noncalcified DCIS, and discuss the importance of this entity.

Abstract P2-16-09: Residual cancer burden in patients with early stage triple negative breast cancer who progress on anthracycline-based neoadjuvant chemotherapy in an ongoing clinical trial (ARTEMIS)

BACKGROUND: Current treatment for early stage triple negative breast cancer (TNBC) includes neoadjuvant systemic chemotherapy (NAST), which is used to assess disease biology and the need for adjuvant treatment in case of residual disease at the time of surgery, also known as residual cancer burden (RCB). Patients with TNBC who experience RCB-0 (pathologic complete response [pCR]) or RCB-I after NAST have an excellent prognosis whereas patients with significant residual disease (RCB-II or RCB-III) are at a high risk of relapse. Standard NAST for TNBC achieves pCR in 30-50% of cases. NAST typically consists of anthracycline-based chemotherapy followed or preceded by a taxane +/- carboplatin. Disease progression (PD) is uncommon in TNBC patients receiving NAST and little is known regarding outcomes in patients who have PD during the initial phase of NAST. METHODS: Total 316 TNBC patients were evaluated from two prospectively accrued clinical trials of NAST (NCT02276443 and NCT01334021). The ARTEMIS trial (NCT02276443) aims to improve pCR rates by adding targeted therapy to chemotherapy as the second phase of NAST for those patients who do not experience at least a 70% volumetric reduction after 4 cycles of doxorubicin/cyclophosphamide (AC). Unique histopathologic features including % stromal tumor-infiltrating lymphocytes (sTIL), presence of mesenchymal histology (high vimentin expression by IHC), and androgen receptor expression are used to guide second phase therapy. RESULTS: 31 TNBC patients had PD while receiving AC as the first phase of NAST (10%; 95% CI= 6.69-13.31%). 9 of 31 patients proceeded to standard chemotherapy and all had RCB II/III disease. 22 of 31 patients were enrolled to targeted therapy trials. 6 were treated with the EGFR inhibitor panitumumab + carboplatin/paclitaxel, 9 with atezolizumab + nab-paclitaxel, and 7 with everolimus, bevacizumab, and liposomal doxorubicin (DAE). Of these 22 patients, 3 (13.6%) had pCR/RCB-0, 1 (4.5%) RCB-I and 18 (81.8%) had RCB II/III. All 4 patients who experienced RCB-0/I had T2N0 disease at diagnosis. 2 had sTIL < 5% and 2 patients had 70% sTIL. CONCLUSION: PD is uncommon while receiving NAST. Patients with TNBC and progression on initial NAST with AC are unlikely to achieve pCR or RCB-I status despite subsequent standard chemotherapy. Combination chemotherapy with targeted therapy on clinical trial resulted in a numerically higher rate of pCR+RCB-I (18%) as salvage therapy, but this was not statistically significant and requires confirmation in larger trials.

Citation Format: Haven Garber, Gaiane Rauch, Beatriz Adrada, Rosalind Candelaria, Elizabeth Mittendorf, Alastair Thompson, Jennifer Litton, Senthil Damodaran, Bora Lim, Banu Arun, Naoto Ueno, Vicente Valero, Nuhad Ibrahim, Rashmi Murthy, Debu Tripathy, Helen Piwnica-Worms, Fraser Symmans, Lei Huo, Stacy Moulder. Residual cancer burden in patients with early stage triple negative breast cancer who progress on anthracycline-based neoadjuvant chemotherapy in an ongoing clinical trial (ARTEMIS) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-16-09.

Abstract P2-16-08: Longitudinal response and selection under neoadjuvant systemic therapy (NAST) in triple-negative breast cancer (TNBC): Profiling results from a randomized, TNBC enrolling trial to confirm molecular profiling improves survival (ARTEMIS; NCT02276443)

Background: The heterogeneity of TNBC results in a spectrum of responses to NAST: 30-40% of patients (pts) have pathologic complete response (pCR) with excellent prognosis. Several methods have been used to measure and evaluate residual disease, including ultrasound, MRI scans, histo-pathology and transcriptional profiling (Seth, ASCO 2019). In addition, we hypothesize that integrative understanding of sub-clonal selection and changes in molecular pathways would lead to better stratification as a biomarker for chemotherapy, and subsequent targeted therapy trials. Methods: Pts with stage I-III TNBC began a planned 4 cycles of Adriamycin-based chemo (AC). Biopsies were performed pre (mandatory) and post (optional) AC. Volumetric change by ultrasound (VUS) at completion of AC (or progression) was calculated. Pts with sensitive disease received subsequent taxane-based (T) therapy. Pts with insensitive disease were offered phase II trials. Pathologic response was assessed at surgical resection in 55 pts. Matched samples, pre and post AC (N = 55 pts) underwent transcriptomic and genomic profiling. Samples were classified into six previously identified ARTEMIS subtypes of TNBC (ART-Type) and immune deconvolution and estimation was performed using RNA-Seq profiles. Somatic mutations and copy-number changes were evaluated using, Mutect, FACETS, and PyClone. Results: Predominately, tumors reacted to AC in 4 different patterns with variation in immune and EMT related pathways. Enrichment of EMT (Group 4) was associated with poor prognosis and higher RCB (10.3% vs 42% pCR rates, p<0.05). The global changes in transcription led to ART-Type switching in all subtypes (44% of pts), except LAR subtype. MYC amplification was more prevalent (40%) in Group 4, associated with higher EMT and poor prognosis than other groups (28%). Phylogenetic evaluation of selection revealed, sub-clonal selection in 22% of evaluable cases with pre and post biopsies. Conclusions: Molecular profiling of longitudinal TNBC samples reveals distinct response patterns in tumors and their micro-environments upon treatment with AC. Integrative analysis of genomic and transcriptomic changes can lead to better stratification of response to NAST. These patterns were indicative of pathologic response in this cohort; however, they require validation in a separate cohort.

Citation Format: Sahil Seth, Lei Huo, Suhas Vasaikar, Gaiane Rauch, Bora Lim, Jason White, Beatriz Adrada, Helen Piwnica-Worms, Naoto T Ueno, Alastair Mark Thompson, Elizabeth Mittendorf, Debashish Tripathy, Jennifer Keating Litton, William Fraser Symmans, Giulio Draetta, Andrew Futreal, Jeffrey Chang, Stacy Moulder. Longitudinal response and selection under neoadjuvant systemic therapy (NAST) in triple-negative breast cancer (TNBC): Profiling results from a randomized, TNBC enrolling trial to confirm molecular profiling improves survival (ARTEMIS; NCT02276443) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-16-08.

Abstract P1-10-20: Serial TILs: Evaluating the role of mid-treatment tumor infiltrating lymphocytes (TIL) in predicting pathologic complete response (pCR) in early-stage triple negative breast cancer (TNBC)

Introduction High levels of TIL at baseline are associated with higher pCR rates and better overall survival in TNBC. Recent studies have also indicated that higher TIL in post-NACT residual disease in TNBC are an important independent predictor of improved survival. We evaluated the role of mid-treatment (post-AC; Adriamycin/Cyclophosphamide) TIL in predicting pCR rates in early-stage TNBC. Methods Of 242 patients with stage I-III TNBC enrolled in the ARTEMIS trial (NCT02276443), 156 patients had pre-AC TIL and pCR status available for this analysis. Both pre-and post-AC TIL counts were available in 29 patients. Post-AC TIL counts for the remaining patients were imputed using linear regression with age, race, stage III, vimentin >50% and post-AC tumor volume reduction. Using these imputed TIL counts we evaluated the association of post-AC TIL with pCR. We also evaluated the change in TIL before and after treatment with AC. Results At baseline the median TIL count was 10% (n=156). In the post-AC samples, the median TIL count was 5%. Using imputed TIL counts, we did not conclude that post-AC TIL was associated with pCR (p= 0.28). Using a cut-point of 15% TIL, our analysis showed that baseline TIL is more strongly correlated with pCR than post-AC TIL (Table 1). In our univariable logistic regression, both baseline TIL and the difference in TIL pre-and post- treatment were significantly associated with pCR (p= 0.0015 and p=0.0068, respectively), however in the multivariable analysis only baseline TIL was significant. Our analysis did show that a decrease in TIL from pre- to post-treatment was significantly associated with pCR (p=0.022). However, this measure was not significant in our logistic regression model when pre-TIL was also included. Conclusion Higher pre-treatment TIL correlated more strongly with pCR rate when compared to post-AC TIL. Pre-treatment high TIL was associated with pCR regardless of changes in TIL pre and post treatment.

Table 1. Changes in TIL before and after treatmentBaseline TILPost-AC TILN#pCR (%)LowLow6217 (27%)LowHigh4012 (30%)HighLow2513 (52%)HighHigh2916 (55%)TIL; Low: <15, High >15

Citation Format: Nour Abuhadra, Kenneth Hess, Jennifer Litton, Gaiane Rauch, Alastair Thompson, Bora Lim, Beatriz Adrada, Elizabeth Mittendorf, Senthil Damodaran, Rosalind Candelaria, Banu Arun, Wei Tse Yang, Naoto Ueno, Lumarie Santiago, Rashmi Murthy, Nuhad Ibrahim, Sahin Aysegul, William Symmans, Lei Huo, Stacy Moulder. Serial TILs: Evaluating the role of mid-treatment tumor infiltrating lymphocytes (TIL) in predicting pathologic complete response (pCR) in early-stage triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-20.

[Parameters influencing the preclinical application of cervical collars]

BACKGROUND

The application of cervical collars is a standard procedure in emergency care of trauma patients. It is often observed that the application of cervical collars is performed incorrectly, which may lead to reduced immobilization of the cervical spine.

OBJECTIVES

The objective of this study was to analyze the practical skills of professional emergency care providers concerning the application of cervical collars.

MATERIALS AND METHODS

Emergency care professionals (n = 104) were asked to apply a cervical collar to a training doll. Each performance step was assessed separately. Furthermore, personal and occupational data of all study participants were collected using a questionnaire.

RESULTS

The study participants included professional rescue personnel and emergency physicians. The average occupational experience of all study participants in out-of-hospital emergency care was 11.1 ± 8.9 years. Most participants had already received training on trauma care (61 %) and felt "very confident" in handling a cervical collar (84 %). The application of the cervical collar was performed correctly in 11 % of the performances. The most common error was incorrect size adjustment of the cervical collar (66 %). No association was found between the correct application of the cervical collar and possible parameters of influence, such as working experience in emergency care or participation in trauma courses.

CONCLUSIONS

Despite pronounced subjective confidence regarding the application of cervical collars, this study shows that there are general deficits in the practical skills of applying cervical collars. Therefore, a critical assessment of the current training contents on the subject of trauma care must be demanded.

Abstract P3-07-01: Towards a therapeutically relevant subtyping scheme for triple-negative breast cancer (TNBC), profiling results from A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival (ARTEMIS)

Triple-negative breast cancer is a highly diverse group of cancers, with poor prognosis, and currently, there are no targeted drugs available in the clinic. In TNBC around 50% percent of the patients respond to chemotherapy, while, the other 50% percent relapse with poor prognosis. There is a need to understand better the targetable mechanisms driving TNBC via integrative analysis of gene-expression, copy-number, and mutational data.

Samples from 220 triple-negative breast cancer (TNBC) pts treated with NACT were prioritized for transcriptomic and genomic profiling. Non-negative matrix factorization was used on array-based profiling to identify six robust (ARTEMIS) subtypes. Comparing ARTEMIS subtypes with Vanderbilt subtypes, revealed significant overlap with 4/6 clusters while identifying two new clusters. Logistic regression on ssGSEA scores vs. subtypes revealed several pathways, selectively enriched specific subtypes. CL1/IM (Immune subtype), was enriched in INFg and INFa, while CL2 (MYC/mTOR), showed enrichment of several proliferation-related pathways. In addition, LAR and M (Mesenchymal) pts formed overlapping clusters, using either method.

Two new subtypes did not associate significantly with any of the previous subtypes. The majority of the tumors from the Vanderbilt BL2 and MSL were reclassified into a CL5 (ANGIO) cluster, which was enriched in angiogenesis geneset, including targetable genes like VEGF and FGFR. Also, an MYO (CL3) subtype was identified, with myogenesis-related genes. Of note, TIL (tumor infiltrating lymphocytes) and LAR quantification using IHC were associated with respective ARTEMIS subtypes. Finally, the IM subtype was significantly associated with higher rates of RCB 0-I and the M (CL4) subtype was associated with higher rates of RCB II-III, irrespective of the neoadjuvant treatment regimen.

ARTEMIS subtypes are a novel classification system for TNBC that is focused on therapeutic translation. Further, we show a possibility to classify previously un-classified (UNS) tumors, which will be validated using additional cohorts (TCGA/METABRIC).

Citation Format: Seth S, Huo L, Rauch G, Lau R, Gilcrease M, Adrada B, Piwnica-Worms H, Symmans WF, Draetta G, Futreal AP, Moulder S, Chang JT. Towards a therapeutically relevant subtyping scheme for triple-negative breast cancer (TNBC), profiling results from A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival (ARTEMIS) [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 P3-07-01.

Abstract P3-01-01: Circulating tumor cells (CTCs) after neoadjuvant chemotherapy for triple negative breast cancer (TNBC)

Background: ARTEMIS (A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival) is a randomized trial to determine if precision guided neoadjuvant chemotherapy (NAC) impacts rates of pathologic complete response in the breast and axillary nodes (pCR). We hypothesized that CTCs in peripheral blood after completion of NAC would provide prognostic information beyond pCR alone in TNBC patients.

Methods: Blood was assessed for CTCs after NAC as part of two IRB approved studies, ARTEMIS (2014 – 0185/PA15-1050), and LAB04-0698. CTCs were identified using the Cell Search® System (Menarini Silicon Biosystems). Samples with one or more cells, also having morphologic criteria for malignancy, were deemed CTC positive. Log-rank test and Cox regression analysis were applied to evaluate associations between CTC positive, pCR, and overall survival.

Results: pCR was achieved in 24/68 (35%) patients with TNBC. Twenty four patients (35%) were CTC positive. Three year overall survival was evaluated in 4 groups of patients: pCR and no CTCs (n=20), pCR and CTC positive (n=4), non-pCR and no CTCs (n=24) and non-pCR and CTC positive (n=20). Three year overall survival was higher in the pCR and no CTCs cohort (100%), compared to pCR and CTC positive (50%), non-pCR and no CTCs (83%), non-pCR and CTC positive (19%); log rank p<0.0001. In the non-pCR and CTC positive patient cohorts, the presence of CTCs was associated with significant risk of death at 3 years [hazard ratio of 12.3 (95% CI 3.4-454, p=0.00002)], whereas a favorable, but non-significant trend was noted for pCR [hazard ratio of 0.2 (95% CI 0.0, 1.4, p=0.11)].

Conclusion: The identification of CTCs after NAC has prognostic significance beyond that of pCR, and should be considered in evaluation of patients for clinical trials of adjuvant therapies.

Citation Format: Lucci A, Hall C, Hess K, Ravenberg E, Clayborn A, Mittendorf E, Rauch G, Candelaria R, Moulder S, Thompson A. Circulating tumor cells (CTCs) after neoadjuvant chemotherapy for triple negative breast cancer (TNBC) [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 P3-01-01.

Abstract P5-05-01: A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment

BACKGROUND: Patient-derived xenograft (PDX) models of breast cancer replicate the diverse histologic and molecular features of patient tumors and provide a renewable source of human tumor tissue. However, collection of tissue by core needle biopsy is problematic due to patient discomfort, bleeding risk and the limited number of passes a patient can tolerate. Several studies have catalogued the maintenance of molecular features of patient tumors in PDX models of breast cancer.

METHODS: To support the neoadjuvant molecular diagnostic and drug development program in triple negative breast cancer (TNBC), a pilot study was conducted to determine if fine needle aspiration (FNA) could be used for building PDX models. Subsequently, PDX models are being established in alignment with ongoing clinical trials at MDACC. The molecular evolution of patient's tumors, matched with PDXs engrafted from their tumors, is under study throughout the neoadjuvant treatment of TNBC using RNA sequencing, whole-exome sequencing, deep sequencing of cancer genes, and histologic analyses.

RESULTS: To date, 20 established PDX models have been developed and stable PDX models continue to be generated at a rate of 2-3 per month. Several of these models are derived from serial FNAs derived from patients throughout neoadjuvant treatment. These models retain histologic and molecular features of the original patient tumors. Serial patient biopsies, matched with PDX models, have enabled measurement of the mutational and transcriptomic evolution in vivo of TNBC undergoing neoadjuvant treatment.

We have standardized the use of FNAs to generate PDX models both pre- and post-neoadjuvant therapy in the following ongoing neoadjuvant clinical trials:

1. MDACC 2014-0185 (PI Stacy Moulder, 360 patients), 'ARTEMIS: A Randomized TNBC-Enrolling trial to confirm Molecular profiling Improves Survival'

2. MDACC 2014-0045 (PI Jennifer Litton, 20+ patients), 'A pilot study of BMN673 as a neoadjuvant study in patients with a diagnosis of invasive breast cancer and a deleterious BRCA mutation'

CONCLUSION: We demonstrated that PDX models from tissue collected by FNA recapitulate the biology and clinical course of the patient's tumor. Sequencing analyses revealed that neoadjuvant chemotherapy and PDX engraftment enrich for cancer gene mutations. We observe association of the rate of successful PDX engraftment with clinical parameters such as the patient's residual cancer burden (RCB) status at the time of surgery (upon completion of neoadjuvant treatment). In addition, we observe that PDX models derived from serial patient biopsies throughout treatment are more resistant to chemotherapy treatment. These models recapitulate the variety of chemotherapy responses observed in patients with TNBC and serve as powerful tools for preclinical biomarker and discovery studies.

Citation Format: Echeverria GV, Cai S, Tu Y, McCoy A, Lau R, Redwood A, Rauch G, Adrada B, Candelaria R, Santiago L, Thompson A, Litton J, Moulder S, Symmans F, Chang JT, Piwnica-Worms H. A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-05-01.

Contemporary breast conservation patient outcomes for ductal carcinoma in situ and margins < 2 mm

559

Background: Recent national consensus guidelines regarding optimal margin width for the management of DCIS have been published; however, controversy remains for managing margins <2mm. The relationship between margin width and locoregional recurrence (LRR) was determined in a contemporary cohort of patients. Methods: 1504 patients with DCIS undergoing definitive breast conserving surgery from 1996 to 2010 were analyzed for clinical and pathologic characteristics from a prospectively managed comprehensive academic cancer center database. Cox proportional hazard models were used to examine the relationship between margin width (<2mm or ≥2mm) and LRR by adjuvant radiation therapy (RT). Patients with positive margins (n=11) were excluded. Results: Overall, 3.4% of patients had a LRR at a median follow-up of 8.7 years. Univariate analysis of age, family history, grade, tumor size, comedonecrosis, RT, adjuvant hormonal therapy, ER status, and margin width found younger age (< 40 yr, p=0.02), no RT (n=299, p=0.005), and margin width <2mm(n=138, p=0.005) to be associated with LRR. The association between margin width and LRR differed by adjuvant radiation therapy status (p=0.02 for the interaction). There was no statistical significant difference in LRR for patients with margins <2mm vs ≥2 mm who received RT, (10-year LRR 6.0% vs 3.2%, respectively; HR 1.5, 95% CI 0.5-4.2, p=0.48). For patients who did not receive RT (n=299), those with margins < 2 mm were significantly more likely to develop a LRR than those with margins ≥2mm (10-year LRR 35.7% vs. 4.6%, respectively; HR 7.2, 95%CI 2.6-19.4, p=0.0001). Conclusions: In patients with <2mm margins receiving adjuvant radiation therapy, there is no difference in locoregional recurrence when compared to patients with ≥2mm margins. Additional surgery for wider margins of resection are not routinely justified in this group of patients but should be obtained for patients with <2mm margins who forego radiotherapy.

A randomized, triple negative breast cancer enrolling trial to confirm molecular profiling improves survival (ARTEMIS)

TPS590

Background: Following neoadjuvant chemotherapy (NACT), patients (pts) with triple negative breast cancer (TNBC) achieving pathologic complete response/residual cancer burden-0 (pCR/RCB-0) or minimal residual disease (RCB-I) have an improved relapse free survival when compared to pts with more extensive residual disease (RCB-II/III) (Symmans et al, JCO 2017). Pts with chemo-resistant TNBC have a poor prognosis as there are currently no FDA-approved targeted agents available for TNBC. We previously reported the ability of a novel gene expression signature (GES) to predict sensitivity to NACT (Hatzis et al, JAMA 2011). Here we seek to prospectively validate the use of this GES in combination with imaging to predict response to NACT and establish the clinical impact of selecting pts predicted to have non-responsive disease (NRD) for enrollment in clinical trials of targeted therapy. Methods: All pts will undergo a biopsy of the primary tumor for molecular characterization (MC) and will be randomized 2:1 to know their MC results (intervention arm) or not (control arm). A maximum of 360 pts will be enrolled and randomized using a group sequential design with one-sided O’Brien-Fleming boundaries, with two equally spaced binding interim tests for futility and superiority and one final test, having an overall Type I error of 0.05 and power of 0.80 to detect an improvement in pCR/RCB-I from 50% to 64%. Secondary endpoints include rates of clinical trial enrollment, disease free survival and integrated biomarker analyses. All pts will receive 4 cycles of anthracycline-based NACT with imaging done every 2 cycles to assess response. After completion or progression on anthracycline-based NACT, pts predicted to have NRD based on MC/imaging (intervention arm) or imaging alone (control arm) will be offered enrollment on a clinical trial. Pts are eligible if they have stage I-III TNBC with a primary tumor that is ≥1.5cm. Pts with contraindications to anthracyclines and/or taxanes are excluded. Enrollment began in November 2015. 105 pts have been enrolled to date with 71 and 34 pts randomized to the intervention and control arms, respectively. Clinical trial information: NCT02276443.

Can Routine Imaging After Neoadjuvant Chemotherapy in Breast Cancer Predict Pathologic Complete Response?

BACKGROUND

This study evaluated breast imaging procedures for predicting pathologic complete response (pCR = ypT0) after neoadjuvant chemotherapy (NACT) for breast cancer to challenge surgery as a diagnostic procedure after NACT.

METHODS

This retrospective, exploratory, monocenter study included 150 invasive breast cancers treated by NACT. The patients received magnetic resonance imaging (MRI), mammography (MGR), and ultrasound (US). The results were classified in three response subgroups according to response evaluation criteria in solid tumors. To incorporate specific features of MRI and MGR, an additional category [clinical near complete response (near-cCR)] was defined. Residual cancer in imaging and pathology was defined as a positive result. Negative predictive values (NPVs), false-negative rates (FNRs), and false-positive rates (FPRs) of all imaging procedures were analyzed for the whole cohort and for triple-negative (TN), HER2-positive (HER2+), and HER2-negative/hormone-receptor-positive (HER2-/HR+) cancers, respectively.

RESULTS

In 46 cases (31%), pCR (ypT0) was achieved. Clinical complete response (cCR) and near-cCR showed nearly the same NPVs and FNRs. The NPV was highest with 61% for near-cCR in MRI and lowest with 44% for near-cCR in MGR for the whole cohort. The FNRs ranged from 4 to 25% according to different imaging methods. The MRI performance seemed to be superior, especially in TN cancers (NPV 94%; FNR 5%). The lowest FPR was 10 % in MRI, and the highest FPR was 44% in US.

CONCLUSION

Neither MRI nor MGR or US can diagnose a pCR (ypT0) with sufficient accuracy to replace pathologic diagnosis of the surgical excision specimen.

Prevalence of atrial fibrillation and association of previous antithrombotic treatment in patients with cerebral microbleeds

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMBs) are associated with an increased risk of intracerebral hemorrhage. The impact of oral anticoagulation (OAC) on CMBs is not well characterized. Our aim was to assess the prevalence of CMBs in stroke and transient ischaemic attack (TIA) patients with atrial fibrillation (AF) and to analyze the implications of previous treatment with OAC.

METHODS

In this retrospective analysis on data from a prospectively recruiting stroke registry, patients with ischaemic stroke or TIA with brain magnetic resonance imaging including susceptibility weighted imaging were consecutively enrolled during a 3-year period. For each patient cardiovascular risk factors, AF history and recent diagnosis of AF, present use of OAC and antiplatelets, the National Institute of Health Stroke Scale and the premorbid modified Rankin Scale score were recorded. Two independent raters identified CMBs according to consensus criteria. CMB location was classified as lobar, deep or in the posterior fossa.

RESULTS

In all, 785 patients (mean age 63.9 ± 14.2 years) were included. At least one CMB was detected in 186 (23.7%) patients. CMBs were significantly more frequent in patients with AF (30.5% vs. 22.4%). Patients with previous OAC treatment were more likely to have CMBs (36.7% vs. 22.8%, P = 0.03) and abundant CMBs (n > 10) were more frequent in anticoagulated patients even after adjustment for age. However, age was the only independent factor predicting CMBs (P = 0.001).

CONCLUSIONS

Cerebral microbleeds are common in elderly AF patients with acute ischaemic stroke. Previous OAC is associated with a higher number of CMBs predominantly in the lobar location. Establishing a causal relationship requires prospective longitudinal investigation.

Prevalence of renal dysfunction in ischaemic stroke and transient ischaemic attack patients with or without atrial fibrillation

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) is associated with a higher risk of stroke and atrial fibrillation (AF). There are limited data on the comorbidity of renal dysfunction and AF in stroke patients. Our aim was to determine the frequency of kidney dysfunction in ischaemic stroke patients with and without AF.

METHODS

In a prospectively collected, single center cohort of acute ischaemic stroke and transient ischaemic attack (TIA) patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation on admission. Renal function was graded into five categories (cat.): cat. 1, eGRF ≥90 ml/min/1.73 m(2); cat. 2, 60-89; cat. 3, 30-59; cat. 4, 15-29; cat. 5, <15. The diagnosis of AF was based on medical history, a 12-lead electrocardiogram (ECG) and 24-h Holter or continuous ECG monitoring.

RESULTS

In total, 2274 patients (1727 stroke, 547 TIA; median age 71.0) were included. Median eGFR was 78.6 ml/min/1.73 m(2) (interquartile range 61/95); 21.1% were in cat. 3, 2.1% in cat. 4, 0.7% in cat. 5. In all, 535 patients (23.5%) suffered from AF; 28.0% of these were in cat. 3, 2.6% and 0.8% in cat. 4 and cat. 5, respectively. In multivariable analysis, age [odds ratio (OR) 1.1], diabetes (OR 1.8), heart failure (OR 1.7) and AF (OR 1.4) were independently associated with kidney dysfunction (eGFR < 60).

CONCLUSIONS

Renal dysfunction is far more common in stroke patients than in the general population and more common in AF-related stroke. These findings may have implications for the choice of anticoagulants.

Die chemische Natur der „Luftphytoncide“ von Blattpflanzen insbesondere von Robinia pseudacacia

Mit einer Versuchsanordnung, bei der nur gasförmige, flüchtige Stoffe erfaßt werden, wurde das Phytoncid von Robinia pseudacacia aus dem Pflanzenbrei isoliert und durch Zonenschmelzen und normales Erstarren angereichert. Durch sein 2.4-Dinitrophenylhydrazon, sein UV- und IR-Absorptionsspektrum sowie durch Synthese konnte es als das Δ2-Hexenal identifiziert werden. Pharmakologisch wirkt es wenig toxisch, zeigt aber als Phytoncid fungizide und protistozide Eigenschaften. Es wurde weiterhin als Phytoncid der Eiche, Erle, Lupine, der schwarzen Johannisbeere, der Heidel- und Preißelbeere sowie des Ligusterstrauches und des Grases erkannt. In Freilandversuchen konnte nachgewiesen werden, daß Δ2-Hexenal auch von unverletzten Pflanzen ausgeschieden wird.

Extraktionsverfahren zur Aufklärung flüchtiger Wirkstoffe von Pflanzen

Es wird ein Extraktionsverfahren beschrieben, mit dem man aus Pflanzenteilen flüchtige Wirkstoffe über die Gasphase schonend isoliert und konzentriert. Damit war es möglich, die Abwehrstoffe der Traubenkirsche Prunus padus aus Blättern, Knospen und Rinde zu isolieren und als Benzaldehyd und Blausäure zu identifizieren. Auch die Blätter der Eberesche Sorbus aucuparia geben Blausäure ab, wenn man sie zerdrückt.

Planning and evaluating clinical trials with composite time-to-first-event endpoints in a competing risk framework

Composite endpoints combine several events of interest within a single variable. These are often time-to-first-event data, which are analyzed via survival analysis techniques. To demonstrate the significance of an overall clinical benefit, it is sufficient to assess the test problem formulated for the composite. However, the effect observed for the composite does not necessarily reflect the effects for the components. Therefore, it would be desirable that the sample size for clinical trials using composite endpoints provides enough power not only to detect a clinically relevant superiority for the composite but also to address the components in an adequate way. The single components of a composite endpoint assessed as time-to-first-event define competing risks. We consider multiple test problems based on the cause-specific hazards of competing events to address the problem of analyzing both a composite endpoint and its components. Thereby, we use sequentially rejective test procedures to reduce the power loss to a minimum. We show how to calculate the sample size for the given multiple test problem by using a simply applicable simulation tool in SAS. Our ideas are illustrated by two clinical study examples.

Do patients with invasive lobular breast cancer benefit in terms of adequate change in surgical therapy from a supplementary preoperative breast MRI?

BACKGROUND

Breast magnetic resonance imaging (MRI) has been introduced in the preoperative management of invasive lobular breast cancer (ILC). We analysed if MRI leads to adequate changes in surgical management.

PATIENTS AND METHODS

We carried out a single-centre retrospective confirmatory analysis of 92 patients with ILC and a preoperative breast MRI. By applying a blinded tumour board method, we analysed if surgical procedures were altered due to breast MRI. In case of alteration, we analysed whether the change was adequate according to the postoperative pathology findings. We considered an adequate rate of change>5% to be a clinically relevant benefit.

RESULTS

A change in surgical therapy due to the MRI findings occurred in 23 of 92 patients (25%). According to the postoperative pathology findings, this change was adequate for 20 of these patients (22%; 95% confidence interval [CI] 14%-31%, P<0.0001). An overtreatment occurred for three patients (3%; 95% CI 0%-6%) who underwent a mastectomy following the results of breast MRI. Patients with larger tumours did likely benefit more from preoperative breast MRI.

CONCLUSIONS

Patients with ILC might benefit from a preoperative breast MRI. Possible harm from overtreatment should be minimised by diligent use of preoperative histological clarification.

Genetic variation in MHC class II expression and interactions with MHC sequence polymorphism in three-spined sticklebacks

Genes of the major histocompatibility complex (MHC) have been studied for several decades because of their pronounced allelic polymorphism. Structural allelic polymorphism is, however, not the only source of variability subjected to natural selection. Genetic variation may also exist in gene expression patterns. Here, we show that in a natural population of three-spined sticklebacks (Gasterosteus aculeatus) the expression of MHC class IIB genes was positively correlated with parasite load, which indicates increased immune activation of the MHC when infections are frequent. To experimentally study MHC expression, we used laboratory-bred sticklebacks that were exposed to three naturally occurring species of parasite. We found strong differences in MHC class IIB expression patterns among fish families, which were consistent over two generations, thus demonstrating a genetic component. The average number of MHC class IIB sequence variants within families was negatively correlated to the MHC expression level suggesting compensatory up-regulation in fish with a low (i.e. suboptimal) MHC sequence variability. The observed differences among families and the negative correlation with individual sequence diversity imply that MHC expression is evolutionary relevant for the onset and control of the immune response in natural populations.

How a complex life cycle can improve a parasite's sex life

How complex life cycles of parasites are maintained is still a fascinating and unresolved topic. Complex life cycles using three host species, free-living stages, asexual and sexual reproduction are widespread in parasitic helminths. For such life cycles, we propose here that maintaining a second intermediate host in the life cycle can be advantageous for the individual parasite to increase the intermixture of different clones and therefore decrease the risk of matings between genetically identical individuals in the definitive host. Using microsatellite markers, we show that clone mixing occurs from the first to the second intermediate host in natural populations of the eye-fluke Diplostomum pseudospathaceum. Most individuals released by the first intermediate host belonged to one clone. In contrast, the second intermediate host was infected with a diverse array of mostly unique parasite genotypes. The proposed advantage of increased parasite clone intermixture may be a novel selection pressure favouring the maintenance of complex life cycles.

Risk factors for cerebral hypoperfusion, mild cognitive impairment, and dementia

Putative risk factors accelerating mild cognitive decline and dementia were correlated with repeated measures of cerebral atrophy, CT, densitometry, perfusions, and cognitive testing among neurologically and cognitively normative aging volunteers. A total of 224 normative subjects at increased risk for cognitive decline were admitted to the study. Mean entry age was 59.5 +/- 15.8 years. Mean follow-up is 5.8 +/- 3.3 years. At follow-up, 22 developed mild cognitive impairment (41 CCSE >/= -3), 19 became demented-8 with Vascular type (VAD), 11 with Alzheimer's type (DAT)-and 183 remain cognitively unchanged. Cerebral atrophy, tissue densities, and perfusions were measured by Xe-CT. After age 60, cerebral atrophy, ventricular enlargement, and polio- and leuko-araiosis geometrically increased as perfusions declined. Risk factors accelerating perfusional decline, cerebral atrophy, polio-araiosis, and leuko-araiosis were: transient ischemic attacks (TIAs), hypertension, smoking, hyperlipidemia, and male gender. At age 71.5 +/- 11.9, mild cognitive impairment began accelerated by TIAs, hypertension and heart disease. Leuko-araiosis began before cognitive decline. TIAs, hypertension, and hyperlipidemia correlated with VAD. Excessive cortical perfusional decrease, gray and white matter hypodensities, and cerebral atrophy correlate with cognitive decline.

Simulation of action potential damping produced by anticonvulsant drugs

Anticonvulsant drugs reduce the ability of central neurones to sustain high-frequency repetitive firing of action potentials. In recent years, it has been demonstrated that this effect is primarily due to a Na+ conductance reduction. We have simulated the electrical behaviour of a neurone, including Ca2+ and various K+ conductances. Although a reduction of Na+ conductance produces a progressive reduction until a complete suppression of the action potential bust, a smaller reduction of this conductance is necessary to produce the same effect when the delayed-rectifier K+ conductance and the Ca2+ conductance are concomitantly reduced . The results indicate that the drugs action on conductances other than Na+ is important for determining their anticonvulsant effect on neurones at therapeutic concentrations.

Prediction of polypeptide secondary structures analysing the oscillation of the hydropathy profile

The hydropathy profile of a polypeptide can reflect periodicity tightly linked, in particular, with alpha-helix and beta-strand conformations. We have developed an algorithm to detect such periodicity to predict the secondary structure of proteins. The method uses profiles constructed with the weighted average of hydropathy along the primary structure of the polypeptide and does the analysis of the variation of the profile for looking for periodic oscillations, using a variation detecting algorithm, without the definition of an empirical threshold. The independence of the method from known structures makes it particularly reliable for analysing membrane proteins.

Coexistent thyroid cancer and pregnancy

OBJECTIVE

A study was performed to determine the appropriate time for the initiation of therapy for thyroid carcinoma first diagnosed during pregnancy.

DATA SOURCES

Material on thyroid cancer cases was obtained from the New Mexico Tumor Registry, Albuquerque, a computerized population-based registry for the state of New Mexico, and the Indian reservation facilities in New Mexico and Arizona (a Surveillance, Epidemiology, and End Results Registry funded by the National Cancer Institute, Bethesda, Md) for the period 1970 to 1991.

STUDY SELECTION

All cases of thyroid cancer, except medullary and anaplastic, in patients aged 18 to 46 years were evaluated. Subgroups were established for (1) all women who were noted to be pregnant at the time of their initial diagnosis and (2) all women with thyroid cancer in the 18- to 46-year-old age group.

DATA EXTRACTION

The information was extracted by a certified tumor registrar for age, sex, thyroid cancer, specific type of thyroid cancer, period, race, year of diagnosis, accession date, last date seen, tumor status, treatment, and patient status.

DATA SYNTHESIS

There have been no deaths in the pregnant group with a follow-up ranging from 0.5 to 20 years. There was no statistically significant difference in observed survival rates between the pregnant group and 465 women, aged 18 to 46 years, with comparable thyroid cancers or in the death rates of women aged 18 to 67 years in the general population.

CONCLUSIONS

Surgical treatment for patients with well-differentiated thyroid cancer diagnosed during pregnancy can be delayed until after parturition.

Secondary structure of noxiustoxin and charybdotoxin from hydropathy power spectra

The analysis of the hydropathy profile power spectra provides a basis for studies of pattern matching between the primary and secondary structure of peptides. The structural motif obtained with Noxiustoxin (NTX), the first K+ channel blocking peptide described, is composed of a N-terminal beta-strand, a central alpha-helix and a final beta-strand zone, probably forming a beta-sheet. These results were compared with those of Charybdotoxin (ChTX), a potent inhibitor of the high conductance Ca(2+)-activated K+ channel, which presents about 48% similarity with NTX in the amino acid sequence. Our prediction for ChTX secondary structure, which is known by 2D-NMR spectroscopy, yielded a Chou-Fasman quality index Q = 90%. The comparison between the two toxins has guided the interpretation of the data obtained.

On the structure of mitochondrial porins and its homologies with bacterial porins

By use of computer modelling, we have predicted a model of 16 transmembrane beta-strands for mitochondrial porins structure from human, Saccharomyces cerevisiae, Neurospora crassa and Dictyostelium discoideum. The proposed model takes into account biochemical and immunological data reported in the literature, as well as electrophysiological results obtained with yeast mitochondrial porins with mutations at selected amino acids. The predicted structure is very similar to that of some bacterial porins, as apparent from the homology of their hydropathic profiles.

Peptides secondary structure prediction with neural networks: a criterion for building appropriate learning sets

Artificial neural networks have been recently applied with success for protein secondary structure prediction. So far, one of the two main aspects on which neural net performance depends, the topology of the net, has been considered. The present work addresses the other main aspect, the building up of the learning set. We present a criterion to build up suitable learning sets based on the alpha-helix percentage. Starting from a set of several well known proteins, we formed 7 groups of proteins with similar helix percentages and we used them for the learning of the same neural net. We found that the best secondary structure prediction for each of the tested proteins (not belonging to the initial set) was the one obtained using the learning set whose helix percentage was closest to that of the tested protein. The accuracy of correct prediction of our method on three types of secondary structure (alpha-helix, beta-sheet and coil), has been compared with the accuracy of other secondary structure prediction methods.

[Diagnosis and therapy of coxitis fugax with special reference to the value of ultrasonographY-assisted diagnosis and hip joint puncture]

Between 1984 to 1991 55 children (mean age 7.0 years) were observed with a painful effusion of the hip examined by ultrasound. Children with radiologically diagnosed hip diseases were excluded. In 47 cases we found a transient synovitis of the hip which started at an average interval of 4 days in mean before admission. All children were reexamined 6 weeks after the end of treatment sonographically and clinically, 4 of those revealing incipient Perthes diseases. The primary sonographic right/left difference in amount of effusion (mean) was 4.0 +/- 1.7 mm and after aspiration 1.5 +/- 1.4 mm with a significantly correlation with the amount of aspirated synovial fluid. The radiological findings for a diagnosis of an effusion of the hip were not reliable. Beside the diagnostic signs of the appearance of the aspirated fluid the sonographic assisted aspiration of the hip is an important treatment mode to reduce the intracapsular pressure and the pain of a hip effusion in children.

Properties of Pseudomonas aeruginosa exotoxin A ionic channel incorporated in planar lipid bilayers

Acidic conditions induce the incorporation of Pseudomonas aeruginosa exotoxin A into phospholipid planar bilayers and the formation of pores permeable to electrolytes. Channel openings occur as single events, although they may occasionally cluster in bursts. In 100 mM KCl, the elementary single channel current amplitude is 3.1 pA (at a transmembrane voltage of 100 mV), the mean open time is 1.3 ms, while bursts may last for several seconds. Noise analysis gave results identical to single channel analysis. Voltage pulse protocols and continuous cycling voltage ramps showed that the toxin channel is voltage dependent, having a higher probability of being open at positive voltages.

Synovial haemangioma of the knee joint

Synovial haemangioma of joints are rare, but usually affect the knee joints of children and adolescents. Recurrent swelling, usually due to haemarthrosis, and intermittent pain may be present for a long time before the diagnosis is made. In this case report the common features of the condition are described, with emphasis on the occurrence of atraumatic haemarthrosis in children. The value of arthroscopy in diagnosis is discussed.

[Biomechanic study of the tensile strength of lyophilized and deep frozen human Achilles tendons following gamma and ethylene oxide sterilization]

By a failed first operation allogenic tissues, as human Achilles tendons are offered for anterior cruciate ligament replacement. The effects of freeze-drying and primary Gamma- or EO-sterilization on the mechanical properties of 62 complete and 74 bisected tendons again fresh frozen controls were investigated under axial tension. A significant decrease of tensile strength for the freeze-dried preparations of 33% for the whole and 43% for the bisected tendons were observed, while Gamma- or EO-sterilizations showed a smaller deleterious effect on the tendons. Considering only the primary mechanical strength complete freeze-dried or complete and bisected irradiated Achilles tendons show sufficient tensile strength for anterior cruciate ligament replacement.