CRTAM promotes antitumor immune response in triple negative breast cancer by enhancing CD8+ T cell infiltration

The immunomodulatory (IM) subtype of triple negative breast cancer (TNBC) exhibits high expression of immune cell signaling genes and is more responsive to immunotherapy. However, the specific mechanism underlying this phenomenon remains unclear. One of the potential key genes appears to be the cytotoxic and regulatory T cell molecule (CRTAM). A cohort of 360 previously untreated TNBC patients from Fudan University Shanghai Cancer Center (FUSCC) underwent RNA sequencing analysis of their primary tumor tissue. Combined with three RNA-seq datasets obtained from the GEO database, a LASSO regression analysis was conducted to identify genes specific to the IM type of TNBC. Our findings revealed elevated CRTAM expression in the IM-type TNBC, which correlated with a favorable overall survival and recurrence-free survival in TNBC patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated a strong association between CRTAM and immune responses as well as immune system processes. Notably, CRTAM overexpression induced STAT1 phosphorylation and upregulation of interferon-stimulated genes. We also found that CRTAM enhanced tumor-associated immune cell infiltration, especially CD8+ T cells, which may be related to the increased expression of MHC class I molecules caused by CRTAM overexpression. These results suggest that CRTAM may serve as a potential biomarker for predicting the efficacy of immunotherapy in TNBC.

Somatic mutations in a multigene panel and impact on prognosis based on TP53 status in Chinese HER2-positive patients undergoing neoadjuvant therapy: A single-institution retrospective cohort

BACKGROUND

Gene mutations play a crucial role in the occurrence and development of tumors, particularly in breast cancer (BC). Neoadjuvant therapy (NAT) has shown greater clinical benefit in HER2-positive breast cancer. However, further clinical investigation is needed to fully understand the correlation between genetic mutations and NAT efficacy and the long-term prognosis in HER2-positive BC.

METHODS

This was a retrospective cohort study of 222 patients receiving NAT between 2017 and 2021 in the Department of Breast Surgery of Fudan University Shanghai Cancer Center. Tumor samples from these patients were subjected to Next Generation Sequencing (NGS) to analyze mutations in 513 cancer-related genes. This study aimed to investigate the association between these genetic mutations and postoperative pathological complete response (pCR), as well as their impact on disease-free survival (DFS).

RESULTS

In total, 48.65% patients reached pCR, ER-negative status (p < 0.001), PR-negative status (p < 0.001), Ki67 ≥ 20 (p = 0.011), and dual-targeted therapy (p < 0.001) were all associated with enhanced pCR rates. The frequency of somatic alterations in TP53 (60%), PIK3CA (15%), and ERBB2 (11%) was highest. In the HER2+/HR- cohort, patients who achieved pCR had a significant benefit in prognosis (HR = 3.049, p = 0.0498). KMT2C (p = 0.036) and TP53 (p = 0.037) mutations were significantly increased in patients with DFS events. Moreover, TP53 mutations had prognostic significance in HER2-positive BC patients with HR-negative (HR = 3.712, p = 0.027) and pCR (HR = 6.253, p = 0.027) status and who received herceptin-only targeted therapy (HR = 4.145, p = 0.011).

CONCLUSIONS

The genetic mutation profiles of Chinese HER2+ patients who received NAT were discrepant with respect to HR status or DFS events. TP53 mutations have significant prognostic value in patients with NAT for HER2-positive BC and patients benefit differently depending on HR status, the neoadjuvant regimen and response, which highlights the significance of genetic factors in treatment customization based on individual genetic and clinical characteristics.

MNX1 Promotes Anti-HER2 Therapy Sensitivity via Transcriptional Regulation of CD-M6PR in HER2-Positive Breast Cancer

Although targeted therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer has significantly prolonged survival time and improved patients' quality of life, drug resistance has gradually emerged. This study explored the mechanisms underlying the effect of the motor neuron and pancreatic homeobox 1 (MNX1) genes on drug sensitivity in HER2-positive breast cancer. From July 2017 to 2018, core needle biopsies of HER2-positive breast cancer were collected from patients who received paclitaxel, carboplatin, and trastuzumab neoadjuvant therapy at our center. Based on treatment efficacy, 81 patients were divided into pathological complete response (pCR) and non-pCR groups. High-throughput RNA sequencing results were analyzed along with the GSE181574 dataset. MNX1 was significantly upregulated in the pCR group compared with the non-pCR group in both sequencing datasets, suggesting that MNX1 might be correlated with drug sensitivity in HER2-positive breast cancer. Meanwhile, tissue array results revealed that high MNX1 expression corresponded to a good prognosis. In vitro functional tests showed that upregulation of MNX1 significantly increased the sensitivity of HER2-positive breast cancer cells to lapatinib and pyrotinib. In conclusion, MNX1 may serve as a prognostic marker for patients with HER2-positive breast cancer, and its expression may facilitate clinical screening of patients sensitive to anti-HER2-targeted therapy.

Immediate Breast Reconstruction After Neoadjuvant Chemotherapy: Factors Associated With Surgical Selection and Complications

BACKGROUND

Breast reconstruction has become an integral component of breast cancer treatment, especially for patients who are unable to undergo breast-conserving surgery after neoadjuvant chemotherapy (NAC). We analyzed factors influencing the type of immediate reconstruction surgery after NAC, as well as the complication rates for each surgery type.

METHODS

The study included patients with breast cancer who underwent mastectomy following NAC from 2010 to 2021. Clinicopathological characteristics, unplanned reoperation rates, and the duration of postoperative hospitalization were analyzed in patients undergoing autologous tissue reconstruction (ATR, n = 127), implant-based reconstruction (IBR, n = 60), and combined autologous tissue and implant reconstruction (n = 60).

RESULTS

A total of 1651 patients who received NAC before mastectomy were enrolled. Among them, 247 (15.0%) patients underwent immediate reconstruction (IR), whereas 1404 underwent mastectomy only. Patients in the IR group were younger ( P < 0.001), had lower body mass index ( P < 0.001), and exhibited earlier clinical ( P = 0.003) and nodal ( P < 0.001) stage than those in the non-IR group. Patients in the ATR group were older ( P < 0.001) and had higher body mass index ( P = 0.007), larger tumor size ( P = 0.024), and more frequent childbearing history ( P = 0.011) than those in the other groups. Complications resulting in unplanned reoperations were more frequent in the IBR group ( P = 0.039). The duration of postoperative hospitalization was longest after ATR ( P = 0.008).

CONCLUSIONS

Age and clinical tumor/nodal stage at presentation are associated with IR for patients undergoing mastectomy after NAC. For patients undergoing IR after NAC, ATR may be safer and more suitable than IBR.

Abstract P3-05-46: scRNA-seq profiling reveals different tumor immune-microenvironment in triple negative breast cancer and decodes pivotal role of THBS1- SDC1 axis in tumor metastasis

ABSTRACT Background: Breast cancer has become the most common cancer worldwide and triple-negative breast cancer (TNBC) is the most aggressive subtype due to the lacks of hormone receptors and HER2 expression. Increasing rate of breast cancer metastasis also need to be solved. Nearly one in four breast cancer patients developed metastasis after treatment, which attributed to 90% cancer related death. Considering highly aggressive pattern of TNBC, TNBC showed higher metastasis probability rather than other subtypes. Therefore, exploring more biomarkers and therapeutic targets are on urgent. Methods: We profiled the transcriptomes of 59646 cells from 12 primary and 4 metastatic tumor samples from Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/). Results: Comparing with primary site, metastatic site was predominated with immunosuppressive tumor microenvironment. In brief, metastatic samples showed increasing numbers of macrophages, lower anti-tumor microenvironment scores, higher malignant cell properties scores, less effective T cells and macrophages, enhanced immune escape potential tumor cells and a later pseudotime state of malignant cells, compared with primary samples. Remarkably, metastatic samples exhibited a stronger interaction of THBS1-SDC1 axis between macrophage subcluster named angiogenesis-1 and malignant cell subcluster named CDKN2A epithelial cells. We subsequently confirmed that higher THBS1-SDC1 expression indicated with poor overall survival and distant metastatic free survival of TNBC patients in The Cancer Genome Atlas (TCGA) TNBC cohort. Conclusion: Our immune landscape of TNBC ecosystem provide deeper insights into tumor metastasis and offer potential biomarkers and therapeutic target for TNBC. Key words: Breast cancer; immune-microenvironment; THBS1; SDC1; metastasis

Citation Format: Liyi Zhang, Qi Zhang, Pei Li, Min Xiong, Yue Zhou, Jingyan Xue, Ming Chen, Wei-Ru Chi, Hengyu Ren, Chih Wan Goh, Douwaner Liu, Liren Wangxu, Yayun Chi, Bingqiu Xiu, Jiong Wu. scRNA-seq profiling reveals different tumor immune-microenvironment in triple negative breast cancer and decodes pivotal role of THBS1- SDC1 axis in tumor metastasis [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 P3-05-46.

Abstract P1-13-15: Elevated TCEAL9 Expression Is Correlated With Trastuzumab-based Neoadjuvant Chemotherapy Resistance In HER2-positive Breast Cancer

Background: -Trastuzumab-based neoadjuvant chemotherapy has shown to have remarkable clinical benefits for HER2-positive breast cancer patients who had higher tumor burden. -Patients who achieved pathological complete response (pCR) are known to have better prognosis. -However, certain patients have little response or are not sensitive to trastuzumab-based treatment regimens. -Understanding the mechanism of trastuzumab resistance is crucial for the development of new therapeutic strategy. Objectives: To investigate the role of TCEAL9 in developing trastuzumab resistance in HER2-positive breast cancer Methods: A total of 83 patients who received paclitaxel, carboplatin and trastuzumab neoadjuvant chemotherapy in Fudan University Shanghai Cancer Center(FUSCC) from 2016 to 2018 were enrolled in this study. After completed neoadjuvant chemotherapy and surgery, gene expressions were compared between the pCR and non-pCR groups. Total RNA from formalin-fixed paraffin-embedded tissue sections was isolated and RNA-sequencing was performed. Gene sets from GEO dataset GSE52707 were used to analyze TCEAL9 expression in resistant and non-resistant cell lines. Gene expression levels were converted into log2 values and row-wised standardized. BT-474 and SK-BR-3 cell lines were transduced with each expression lentivirus, followed by selection with puromycin for stable expression. TCEAL9 mRNA and protein level evaluation was evaluated by qPCR and western blot. The influence of TCEAL9 expression on proliferation and sensitivity to HER2-targeted therapy was evaluated by CCK8. BT-474 and SK-BR-3 transfected cells were plated in 96-well plates with 4,000 cells per well. After 3 or 5 days of incubation with trastuzumab, pertuzumab or lapatinib, the viability of cells was measured using Cell Proliferation Assay. Comparisons between Kaplan-Meier curves were performed using the long-rank test. Results: TCEAL9 was elevated significantly (P&lt; 0.05) in non-pCR patients in the FUSCC cohort and was associated with lapatinib resistance in GSE52707 from GEO datasets. Patients with elevated TCEAL9 expression had worse recurrence-free survival (RFS), distant metastasis-free survival (DMFS) and progression-free survival (PPS) (all P&lt; 0.05)by using KM-plotter. Overexpression of TCEAL9 was associated with lapatinib(IC50= 5.56 vs 10.90nM) and trastuzumab + pertuzumab(IC50= 745 vs 635nM) resistance in BT-474 and SK-BR-3 respectively, but has no influence in proliferation. In this study, we found that TCEAL9 could induce HER2-positive breast cancer cells resistance to HER2-targeted therapy through the activation of mTOR signaling pathway. After EGFR stimulation, TCEAL9 has a higher mTOR phosphorylation level in BT-474 cells. TCEAL9 elevation also increased HER2 and mTOR phosphorylation after lapatinib treatment in SK-BR-3 cells. In addition, the elevation of TCEAL9 has a positive correlation with HER2 signaling pathways such as EGFR, PIK3R1, FOXO1 and AKT3 in TCGA datasets. Conclusions: TCEAL9 expression correlates with trastuzumab resistance and high TCEAL9 expression is associated with poor prognosis in HER2-positive breast cancer patients.

Citation Format: Chih Wan Goh, Wei-Ru Chi, Liyi Zhang, Qi Zhang, Ming Chen, Min Xiong, Douwaner Liu, Hengyu Ren, Bingqiu Xiu, Jingyan Xue, Yayun Chi, Jiong Wu. Elevated TCEAL9 Expression Is Correlated With Trastuzumab-based Neoadjuvant Chemotherapy Resistance In HER2-positive 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 P1-13-15.

Abstract P1-05-31: A single center retrospective analysis of 259 cases of metaplastic breast cancer

Introduction: Metaplastic breast cancer (MBC) is a rare breast tumor.WHO histological classification of breast tumors in 2019 divided MBC into the following seven types: low-grade adenosquamous carcinoma, fibromatoid metaplastic carcinoma, squamous cell carcinoma, spindle cell carcinoma, metaplastic carcinoma with mesenchymal differentiation, mixed metaplastic carcinoma and myoepithelial carcinoma. Based on single center data, this study intends to conduct a detailed analysis of the clinicopathological features, treatment and prognostic factors of MBC. Methods:We collected 259 MBCs treated in our center from 2006 to 2022. The patient’s age, histological type, image feature, tumor size, lymph node metastasis, tumor stage, immunohistochemical information, surgical plan and systemic adjuvant therapy were summarized and considered to explore the factors affecting the overall survival rate (OS) and disease-free survival rate (DFS). T-test and chi-square test were performed on the data. P&lt; 0.05 showed that the difference was statistically significant. Kaplan-Meier survival was used to analyze the long-term efficacy. Results: The incidence rate of MBC in breast cancer patients in our center is about 0.5%. They included 105 cases of squamous cell carcinoma (40.5%), 49 cases of mixed metaplastic carcinoma (18.9%), 41 cases of spindle cell carcinoma (15.8%), 27 cases of metaplasia carcinoma secreting matrix (10.4%), 6 cases of metaplastic carcinoma with mesenchymal differentiation (2.3%), 6 cases of myoepithelial carcinoma (2.3%), 3 cases of low-grade adenosquamous carcinoma (1.2%), 1 case of fibromatoid metaplasia carcinoma (0.4%) and 21 cases of unknown (8.1%). MBC were mainly three negative subtypes, which were 204 cases (78.8%), 41 cases (15.8%) luminal subtypes and 14 cases (5.4%) HER2 positive subtypes. There was no significant difference in the distribution of breast cancer subtypes among different histological types of MBC. There were 63 cases (24.3%) in clinical stage I, 171 cases (66.0%) in stage II, 23 cases (8.9%) in stage III and 2 cases (0.8%) in stage IV. 58 patients underwent core needle biopsy, of which only 7 (12.1%) reported histological types consistent with MBC. Among 154 patients with molybdenum target reports, 59 of them (38.3%) had malignant calcifications. The diagnostic coincidence rates of MRI, ultrasound and molybdenum target were 90.0%, 85.1% and 74.7% respectively. 258 cases of MBC received surgical treatment, including 183 cases of total mastectomy (70.9%), 53 cases of breast conserving surgery (20.5%) and 22 cases of quadrant resection (8.5%); 132 patients (51.2%) underwent axillary lymph node dissection and 93 patients (36.0%) underwent sentinel lymph node biopsy. 24 patients (9.3%) received neoadjuvant chemotherapy, of which only 2 (8.3%) achieved pathological complete remission. 56 patients (21.6%) received adjuvant radiotherapy, with a median of 25 times. 167 patients (64.5%) received adjuvant chemotherapy, and anthracycline sequential paclitaxel was the most commonly used regimen. The median follow-up was 31 months. The five-year DFS was 82.0%, and the five-year OS was 89.4%. Through Cox regression analysis, it was found that patients’ N stage (P=0.036) and receiving anthracycline sequential paclitaxel adjuvant chemotherapy (P=0.004) were independent prognostic factors. Conclusion: The histological types of MBC are complex. MRI is of high value in diagnosis. Conventional CNB is difficult to meet the needs of pathological tissue classification. Patients without lymph node metastasis and receiving anthracycline sequential paclitaxel adjuvant chemotherapy are associated with better prognosis. Through multidisciplinary standardized diagnosis and treatment, there is no significant difference between the prognosis of MBC and the common types of breast cancer. Keyword: metaplastic breast cancer; pathological characteristics; imaging; treatment; prognosis.

Citation Format: Douwaner Liu, Jiajian Chen, Shuang Hao, Bingqiu Xiu, Qi Zhang, Liyi Zhang, Guangyu Liu, Zhimin Shao, Jiong Wu. A single center retrospective analysis of 259 cases of metaplastic 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 P1-05-31.

Abstract P1-13-05: Extracellular vesicles-transported lncRNA BCDR1 promotes tumor cell proliferation and therapy resistance via upregulating G1/S-phase transition in breast cancer

Background Extracellular vesicles (EVs), secreted by tumor cells for intercellular communication, play an important role in breast cancer progression. Previous studies have proved that lncRNA could use EVs to transmit signals and affect the progression and treatment of breast cancer. In addition, a previous study has found that, in HER2 therapy-resistant tumors, CDK4/6 activity and cell cycle progression genes were involved and might serve as treatment targets. However, recent clinical trials were not supportive of the use of CDK4/6 inhibitors in HER2 enriched internal subtypes of breast cancer. In this study, we aim to explore the role of EVs-transported long noncoding RNA BCDR1 in the promotion of cell cycle progression in HER2-positive breast cancer, exploring a new potential target in combination with CDK4/6 inhibitor and anti-HER2 treatment. Methods Samples were collected from patients with HER2 overexpression receiving neoadjuvant therapy. RNA-seq was performed to identify differentially expressed RNAs between pathological complete response (pCR) and non-pCR group. In addition, serum extracellular vesicles were collected and determined through RNA-seq. The drug response and proliferation rate of tumor cells were measured in breast cancer cells (HCC-1954, BT-474 and MCF-7). Quantitative RT-PCR (qRT-PCR) was used to detect the expression levels of BCDR1 and its potential target genes. RNA-seq and GSEA analysis was carried out to determine the target pathways regulated by BCDR1. DNA fiber assay, mass spectrometry, and flow cytometry were used to understand the underlying mechanism of BCDR1. Results Core needle biopsy tissues from HER2-positive breast cancer patients with any ER status were collected before NAC. Among genes differentially overexpressed, BCDR1 was found to be downregulated in pCR group compared with non-pCR group. BCDR1 was also elevated in plasma EVs in the non-pCR group. In addition, overexpression of BCDR1 in breast cancer cells promoted cell proliferation and HER2 treatment resistance. Through pathway analysis, we found BCDR1 could facilitate G1/S-phase transition. Flow cytometry confirmed these findings. We also noticed that proteins that regulate DNA licensing including minichromosome maintenance proteins (MCMs) were enriched in BCDR1 overexpression cells. Through DNA fiber assay, we confirmed that BCDR1 could promote DNA replication initiation. Interestingly, under CDK4/6 inhibitor treatment, BCDR1 was induced, unrevealing an internal treatment-resistant mechanism in these tumor cells. Through EVs RT-qPCR, we found BCDR1 could transport from high expression cells to low, with the same biological function. We also explored antisense oligonucleotide (ASO) use in the inhibition of BCDR1 biological function and transportation. Conclusion BCDR1 promotes cell proliferation and therapy resistance via upregulating DNA licensing in breast cancer. BCDR1 could transported through EVs with same biological function. This study also suggests that BCDR1 could serve as a biomarker and therapeutic target in breast cancer.

Citation Format: Qi Zhang, Bingqiu Xiu, Yayun Chi, Jiong Wu. Extracellular vesicles-transported lncRNA BCDR1 promotes tumor cell proliferation and therapy resistance via upregulating G1/S-phase transition in 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 P1-13-05.

Abstract P1-07-07: Cross-talk of Four Types of RNA Modification Proteins with Adenosine Reveals the Landscape of Multivariate Prognostic Patterns in Breast Cancer

Background: BRCA is the most common malignant tumour, and its heterogeneity is one of its major characteristics. m6A, m1A, APA, and A-to-I RNA editing constitute the four most common adenosine-associated RNA modifications and represent the most typical and critical forms of epigenetic regulation contributing to the immunoinflammatory response, tumorigenesis and tumour heterogeneity. However, the cross-talk and potential combined profiles of these RMPs in multivariate prognostic patterns of BRCA remain unknown. Methods: A total of 48 published RMPs were analysed and found to display significant expression alterations and genomic mutation rates between tumour and normal tissues in the TCGA-BRCA cohort. Data from 4188 BRCA patients with clinical outcomes were downloaded from the GEO, METABRIC and TCGA databases, normalized and merged into one cohort. The prognostic value and interconnections of these RMPs were also studied. The four PRGs with the greatest prognostic value were then selected to construct diverse RMP-associated prognostic models through uniCox, differential expression analysis, LASSO regression and multiCox. Alterations in biological functional pathways, genomic mutations, immune infiltrations, RNAss scores and drug sensitivities among different models, as well as their prognostic value, were then explored. Results: Utilizing a large number of samples and a comprehensive set of genes contributing to adenosine-associated RNA modification, our study revealed the joint potential bio-functions and underlying features of these diverse RMPs and provided effective models (PRG clusters, gene clusters and the risk model) for predicting the clinical outcomes of BRCA. The individuals with higher risk scores showed poor prognoses, cell cycle function enrichment, upregulation of stemness scores, higher TMBs, immune activation and specific drug resistance. This work highlights the significance of comprehensively examining post-transcriptional RNA modification genes. Conclusions: Here, we designed and verified an advanced forecasting model to reveal the underlying links between BRCA and RMPs and precisely predict the clinical outcomes of multivariate prognostic patterns for individuals.

Citation Format: Xuliren Wang, Min Xiong, Bingqiu Xiu, Jiong Wu, Yayun Chi. Cross-talk of Four Types of RNA Modification Proteins with Adenosine Reveals the Landscape of Multivariate Prognostic Patterns in 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 P1-07-07.

Abstract P5-02-41: UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization

Background: In the past 20 years, the efficacy and prognosis of HER2-positive breast cancer have significantly improved. However, nearly 50% of patients still have residual invasive tumors after chemotherapy combined with dual-targeted neoadjuvant therapy, especially for those with disease progression during treatment. A lack of effective therapeutic regimens results from the failure of targeted therapy, whose heterogeneity is especially worthy of our attention. The aim of this study was to look for efficacy markers and investigate new drug-resistance mechanisms. Methods: Firstly, the high-throughput sequencing data from 81 patients who received neoadjuvant chemotherapy TCbH (paclitaxel + carboplatin + trastuzumab) was analyzed by the efficacy outcomes. They were divided into 8 patients with stable or progressive disease (SD/PD), 35 with partial response (PR), and 38 with pathological complete remission (pCR). Then, UBE2E3 was chosen from the different expression genes between SD/PD and pCR based on efficacy results and the weighted gene co-expression network (WGCNA). UBE2E3 clinical correlations were investigated using publicly available data from The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), and UBE2E3 was validated using immunohistochemistry (IHC) on 200 HER2-positive breast cancer tissue chips. Further, the UBE2E3 knockdown and overexpression stable transfer cell lines were constructed, and the effects of UBE2E3 on cell proliferation, clone formation, and drug sensitivity were verified by live cell imaging, the CCK8 assay, plate cloning, and IC50 assays, respectively. The tumor growth of UBE2E3 in vivo was investigated by an in situ transplantation tumor assay in nude mice. Meanwhile, the p-RB assay of mouse tissues by IHC was used to explore the effect of UBE2E3 on cell proliferation. RNA-seq was used to screen the downstream molecules of UBE2E3. Western blotting was used to verify the results of bioinformatics analysis and to explore the downstream key molecules. The protease inhibitor MG132 and actinomycin CHX were used to look at the effect on the stability of the target protein. Immunoprecipitation and silver staining assays were used to find interacting proteins with the UBE2E3. Results: Ten hub-genes which were efficacy-related were identified by WGCNA analysis, in which UBE2E3 was highly expressed in the SD/PD group (p &lt; 0.05). In HER2-positive breast cancer, high expression of UBE2E3 was associated with poor prognosis and decreased disease-free survival both in public data and Fudan University Shanghai Cancer Center (FUSCC) data [HR 2. 36, (1.25–4.47), p &lt; 0.05]. The experimental results demonstrated that UBE2E3 promoted the proliferation of HER2-positive breast cancer cells, enhanced clone formation, and resisted lapatinib’s treatment in cellular phenotype; and that UBE2E3 promoted tumor growth in vivo and upregulated the expression of p-RB. The differentially expressed genes’ sets of the RNA-seq between overexpressed cell lines and control showed that overexpressing UBE2E3 activated the EGFR pathway. Further, an immunoblot assay confirmed that UBE2E3 positively regulated EGFR levels and activated the downstream MAPK pathway. The proteasome inhibitor MG132 and CHX assays showed that UBE2E3 could stabilize EGFR proteins. The co-immunoprecipitation and silver staining assays showed that UBE2E3 stabilized EGFR proteins by interacting with c-Cbl. Conclusion: UBE2E3 could negatively affect the efficacy of HER2-positive breast cancer therapy and is significantly associated with poor prognosis. UBE2E3 may serve as a potential marker of efficacy and prognosis for HER2-positive breast cancer in the future. Therapeutic efficacy is affected by UBE2E3, which binds to c-Cbl and causes upregulation of EGFR expression in vivo, which in turn causes the MAPK pathway to be activated and tumor growth to be pushed up.

Citation Format: Pei Li, Wei-Ru Chi, Bingqiu Xiu, Qi Zhang, Liyi Zhang, Ming Chen, Jingyan Xue, Xiaoyan Huang, Yayun Chi, Jiong Wu. UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization [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 P5-02-41.

Abstract P5-02-53: P95HER2 Expression in HER2-Positive Breast Cancer

Background: -HER2-positive breast cancer subtype accounted for around 15-20% of all breast cancer. -The introduction of HER2-targeted therapy such as trastuzumab and pertuzumab has remarkably increased the patients’ prognosis of HER2-positive breast cancer. -However, resistance exists due to impaired drug binding to HER2 receptor and constitutive activation of HER2 downstream signaling pathways. -P95HER2 isoform is a truncated form of HER2 that retains the C terminal domain but lacks an N terminal trastuzumab binding site, leading to trastuzumab resistance in HER2-positive breast cancer. -A new P95HER2 antibody is developed to target the extracellular domain of p95HER2 in formalin-fixed paraffin-embedded (FFPE) HER2-positive breast cancer tissues by using hematoxylin and eosin (HE) staining method. Objectives: To evaluate the expression of P95HER2 and its clinicopathological characteristics in HER2-positive breast cancer. Methods: We assessed 68 HER2-positive patients (IHC 3+ or IHC 2+/in situ hybridization [ISH]+) from Fudan University Shanghai Cancer Center (FUSCC) who underwent breast cancer surgery and were treated with adjuvant chemotherapy (taxane or anthracycline or combination) plus trastuzumab from 2014 to 2016. P95HER2 HE antibody is provided by Simcere Pharma. In this study, we compared 27 patients with primary trastuzumab resistance with 41 non-relapse breast cancer patients. 14 patients have not received trastuzumab targeted therapy. P95HER2 staining of either 1+, 2+ or 3+ observed in any tumor area in HE slides was considered to be P95 HER2 positive. Chi-square test was used to determine the relationship between P95HER2 expression of patients’ characteristics. The main outcome measures were disease free-survival (DFS), distant disease-free survival (DDFS) and overall survival (OS) by using log-rank test. Univariable and multivariable Cox regression analyses were used to identify independent factors related to prognosis. Results: From 2014 to 2016, we assessed the expression of P95HER2 expression in 68 HER2 positive breast cancer patients from FUSCC. Median follow-up was 45 months. In our study, 19 (27.9%) were P95HER2 positive. P95HER2 positive expression rate is higher in premenopausal patients than in postmenopausal patients (68.4% vs 38.8%, P= 0.028). Univariable analysis showed that higher T-stage (P= 0.018), higher N-stage (P= 0.001) and P95HER2 positive expression (P= 0.033) were associated with worse DDFS. Multivariable analysis showed that higher T-stage (hazard ratio, 6.019; 95% CI, 1.205-30.078; P= 0.029) and P95HER2 positive (hazard ratio, 2.349; 95%CI, 1.03-5.358; P= 0.042) independently predicted worse DDFS. P95HER2 positive was significantly associated with shorter 5-year DDFS (42.1% vs 67.6%, P= 0.028), but has no significant difference in DFS (36.8% vs 59.5%, P= 0.072) and OS (74.8% vs 81.2%, P= 0.685). Conclusions: P95HER2 positive was found more in premenopausal patients and was associated with a higher metastasis rate, indicating that P95HER2 expression tends to be a more aggressive isoform type of HER2-positive breast cancer. P95HER2 may serve as a therapeutic target for anti-HER2 therapy.

Citation Format: Chih Wan Goh, Liyi Zhang, Wei-Ru Chi, Bingqiu Xiu, Jiajian Chen, Wenqing Yang, Chunxia Ao, Jianxing Tang, Jingyan Xue, Yayun Chi, Jiong Wu. P95HER2 Expression in HER2-Positive 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 P5-02-53.

Abstract P2-16-04: MNX1 promotes tumor sensitivity to HER2-targeted therapy in HER2-positive breast cancer

Background: Female breast cancer has been the world’s leading cancer incidence among women. HER2-positive breast cancer accounts for about 15%~20% of all breast cancer, with a high degree of malignancy and easy metastasis and recurrence. With the development of medical technology and the continuous innovation of HER2 targeting drugs, patients with HER2-positive breast cancer have more treatment options and their prognosis had been greatly improved. However, there is still a lack of biomarkers for HER2-positive early breast cancer in clinical practice. Methods: This study prospectively collected single-center (Fudan University Shanghai Cancer Center, FUSCC) preoperative core needle biopsy samples of breast cancer patients from July 2017 to July 2018 who received neoadjuvant paclitaxel, carboplatin plus with trastuzumab (PCH). The patients were divided into pCR and non-PCR groups, and 81 patients were enrolled. The differential expression of genes was screened and validated by RNA-seq. The gene expression data for GSE181574 (this database has a total of 105 cases of breast cancer tissue samples were collected by core needle biopsy before neoadjuvant treatment. 52 cases underwent Ado-trastuzumab emtansine plus pertuzumab, 9 cases of paclitaxel plus trastuzumab, and 44 cases of paclitaxel plus trastuzumab and pertuzumab), GSE52707 (SK-BR-3 Lapatinib resistance cell group vs control group), and GSE15043 (BT474 Herceptin-resistant cell group vs control group), were downloaded from the Gene Expression Omnibus (GEO) database. Cell cloning formation, proliferation assay, and drug sensitivity experiments were conducted in MNX1 ectopic and knockdown cell lines. Co-IP assay, RNA-Seq, and ChIP-Seq analysis were used to explore the downstream pathways that MNX1 might be involved. Results: High-throughput sequencing results of core needle biopsy samples from 81 HER2-positive breast cancer patients were divided into pCR and non-pCR groups. Using DEseq2 packet analysis to screen differentially expressed genes, P-value &lt; 0.05, | log2FoldChange | &gt; 1 as the filter, there were 620 up-regulated genes and 715 down-regulated genes in the pCR group. The same method was used for the analysis of the GSE181574 data set. Combined the two datasets used P values and log2FoldChange (P-value &lt; 0.05, | log2FoldChange | &gt; 1.2) as selection criteria, we found the MNX1 and PNMT expressions were significantly higher in the pCR group. Subsequently, differential analysis of GSE52707 and GSE15043 datasets showed that MNX1 and PNMT expression levels were reduced in drug-resistant cell lines. Considering the P-value and | log2FoldChange |, we ultimately selected motor neuron and pancreatic homeobox 1(MNX1) gene as the target factors for follow-up studies. In the cloning formation and proliferation assay, overexpression of MNX1 inhibits proliferation and clonal formation of HER2-positive breast cancer cells. In the drug sensitivity experiments overexpression of MNX1 enhances the sensitivity of HER2-positive breast cancer cells to tyrosine kinase inhibitors (TKI) such as lapatinib and pyrotinib. MNX1 knockdown reduces the sensitivity of HER2-positive breast cancer cells to TKI. Through RNA-seq and ChIP-seq, we found that CD-M6PR might be a downstream target gene regulated by MNX1. Verification by Dual-Luciferase Reporter Assay MNX1 was found to positively regulate CD-M6PR transcription. By Co-IP assay, it was found that MNX1 interacted with EEF1D, and EEF1D stabilized MNX1. MNX1 and CD-M6PR affect the proliferation and drug sensitivity of breast cancer cells by down-regulating the PI3K-AKT-mTOR pathway. Conclusion: Overexpression of MNX1 increases the sensitivity of HER-2 positive cells to TKI. MNX1 binds to EEF1D and is stabilized by EEF1D. MNX1 positively regulates M6PR and affects the proliferation of breast cancer cells and the sensitivity of breast cancer cells to TKI through the PI3K-AKT-mTOR pathway.

Citation Format: Wei-Ru Chi, Bingqiu Xiu, Min Xiong, Pei Li, Qi Zhang, Lun Li, Jianjing Hou, Xujie Zhou, Yuting Sang, Ming Chen, Liyi Zhang, Jingyan Xue, Yayun Chi, Jiong Wu. MNX1 promotes tumor sensitivity to HER2-targeted therapy in HER2-positive 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 P2-16-04.

LINC00478-derived novel cytoplasmic lncRNA LacRNA stabilizes PHB2 and suppresses breast cancer metastasis via repressing MYC targets

BACKGROUND

Metastasis is the predominant cause of mortality in patients with breast cancer. Long noncoding RNAs (lncRNAs) have been shown to drive important phenotypes in tumors, including invasion and metastasis. However, the lncRNAs involved in metastasis and their molecular and cellular mechanisms are still largely unknown.

METHODS

The transcriptional and posttranscriptional processing of LINC00478-associated cytoplasmic RNA (LacRNA) was determined by RT-qPCR, semiquantitative PCR and 5'/3' RACE. Paired-guide CRISPR/cas9 and CRISPR/dead-Cas9 systems was used to knock out or activate the expression of LacRNA. Cell migration and invasion assay was performed to confirm the phenotype of LacRNA. Tail vein model and mammary fat pad model were used for in vivo study. The LacRNA-PHB2-cMyc axis were screened and validated by RNA pulldown, mass spectrometry, RNA immunoprecipitation and RNA-seq assays.

RESULTS

Here, we identified a novel cytoplasmic lncRNA, LacRNA (LINC00478-associated cytoplasmic RNA), derived from nucleus-located lncRNA LINC00478. The nascent transcript of LINC00478 full-length (LINC00478_FL) was cleaved and polyadenylated, simultaneously yielding 5' ends stable expressing LacRNA, which is released into the cytoplasm, and long 3' ends of nuclear-retained lncRNA. LINC00478_3'RNA was rapidly degraded. LacRNA significantly inhibited breast cancer invasion and metastasis in vitro and in vivo. Mechanistically, LacRNA physically interacted with the PHB domain of PHB2 through its 61-140-nt region. This specific binding affected the formation of the autophagy degradation complex of PHB2 and LC3, delaying the degradation of the PHB2 protein. Unexpectedly, LacRNA specifically interacted with PHB2, recruited c-Myc and promoted c-Myc ubiquitination and degradation. The negatively regulation of Myc signaling ultimately inhibited breast cancer metastasis. Furthermore, LacRNA and LacRNA-mediated c-Myc signaling downregulation are significantly associated with good clinical outcomes, take advantage of these factors we constructed a prognostic predict model.

CONCLUSION

Therefore, our findings propose LacRNA as a potential prognostic biomarker and a new therapeutic strategy.

Immunosuppressive lncRNA LINC00624 promotes tumor progression and therapy resistance through ADAR1 stabilization

BACKGROUND

Despite the success of HER2-targeted therapy in achieving prolonged survival in approximately 50% of treated individuals, treatment resistance is still an important challenge for HER2+ breast cancer (BC) patients. The influence of both adaptive and innate immune responses on the therapeutic outcomes of HER2+BC patients has been extensively demonstrated.

METHODS

Long non-coding RNAs expressed in non-pathological complete response (pCR) HER2 positive BC were screened and validated by RNA-seq. Survival analysis were made by Kaplan-Meier method. Cell death assay and proliferation assay were performed to confirm the phenotype of LINC00624. RT-qPCR and western blot were used to assay the IFN response. Xenograft mouse model were used for in vivo confirmation of anti-neu treatment resistance. RNA pull-down and immunoblot were used to confirm the interaction of ADAR1 and LINC00624. ADAR1 recombinant protein were purified from baculovirus expression system. B16-OVA cells were used to study antigen presentation both in vitro and in vivo. Flow cytometry was used to determine the tumor infiltrated immune cells of xenograft model. Antisense oligonucleotides (ASOs) were used for in vivo treatment.

RESULTS

In this study, we found that LINC00624 blocked the antitumor effect of HER2- targeted therapy both in vitro and in vivo by inhibiting type I interferon (IFN) pathway activation. The double-stranded RNA-like structure of LINC00624 can bind and be edited by the adenosine (A) to inosine (I) RNA-editing enzyme adenosine deaminase RNA specific 1 (ADAR1), and this editing has been shown to release the growth inhibition and attenuate the innate immune response caused by the IFN response. Notably, LINC00624 promoted the stabilization of ADAR1 by inhibiting its ubiquitination-induced degradation triggered by β-TrCP. In contrast, LINC00624 inhibited major histocompatibility complex (MHC) class I antigen presentation and limited CD8+T cell infiltration in the cancer microenvironment, resulting in immune checkpoint blockade inhibition and anti-HER2 treatment resistance mediated through ADAR1.

CONCLUSIONS

In summary, these results suggest that LINC00624 is a cancer immunosuppressive lncRNA and targeting LINC00624 through ASOs in tumors expressing high levels of LINC00624 has great therapeutic potential in future clinical applications.

Cross-talk of four types of RNA modification proteins with adenosine reveals the landscape of multivariate prognostic patterns in breast cancer

Background: Breast cancer (BC) is the most common malignant tumour, and its heterogeneity is one of its major characteristics. N6-methyladenosine (m6A), N1-methyladenosine (m1A), alternative polyadenylation (APA), and adenosine-to-inosine (A-to-I) RNA editing constitute the four most common adenosine-associated RNA modifications and represent the most typical and critical forms of epigenetic regulation contributing to the immunoinflammatory response, tumorigenesis and tumour heterogeneity. However, the cross-talk and potential combined profiles of these RNA-modified proteins (RMPs) in multivariate prognostic patterns of BC remain unknown.

Methods: A total of 48 published RMPs were analysed and found to display significant expression alterations and genomic mutation rates between tumour and normal tissues in the TCGA-BRCA cohort. Data from 4188 BC patients with clinical outcomes were downloaded from the Gene Expression Omnibus (GEO), the Cancer Genome Atlas (TCGA), and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), normalized and merged into one cohort. The prognostic value and interconnections of these RMPs were also studied. The four prognosis-related genes (PRGs) with the greatest prognostic value were then selected to construct diverse RMP-associated prognostic models through univariate Cox (uniCox) regression analysis, differential expression analysis, Least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox (multiCox) regression. Alterations in biological functional pathways, genomic mutations, immune infiltrations, RNAss scores and drug sensitivities among different models, as well as their prognostic value, were then explored.

Results: Utilizing a large number of samples and a comprehensive set of genes contributing to adenosine-associated RNA modification, our study revealed the joint potential bio-functions and underlying features of these diverse RMPs and provided effective models (PRG clusters, gene clusters and the risk model) for predicting the clinical outcomes of BC. The individuals with higher risk scores showed poor prognoses, cell cycle function enrichment, upregulation of stemness scores, higher tumour mutation burdens (TMBs), immune activation and specific drug resistance. This work highlights the significance of comprehensively examining post-transcriptional RNA modification genes.

Conclusion: Here, we designed and verified an advanced forecasting model to reveal the underlying links between BC and RMPs and precisely predict the clinical outcomes of multivariate prognostic patterns for individuals.

Stabilization of CCDC102B by Loss of RACK1 Through the CMA Pathway Promotes Breast Cancer Metastasis via Activation of the NF-κB Pathway

Background

Breast cancer is one of the leading causes of cancer-related death among women, and the pathological status of axillary lymph nodes is an important predictor of prognosis. However, the mechanism involved in this early stage of metastasis remains largely unknown.

Methods

Microarray analysis was used to carry out differential genomics analyses between matched pairs of metastatic sentinel lymph node tissues and breast primary tumors. The CRISPR/Cas9 gene editing system was used for in vivo screening by transplanting a loss-of-function cell pool into immunocompromised mice. MAGeCK was used to analyze the screening results. Survival analysis was performed via the Kaplan–Meier method. Cell proliferation, wound healing, migration and invasion assays were performed to confirm the phenotype. A tail vein model and subcutaneous xenotransplanted tumor model were used for the in vivo study. The relationship between coiled-coil domain containing 102B (CCDC102B) and receptor for activated C kinase 1 (RACK1) was examined using coimmunoprecipitation, mass spectrometry, nuclear protein extraction and immunofluorescence assays. The primary biological functions and pathways related to CCDC102B were enriched by RNA sequencing.

Results

We identified CCDC102B through screening and found that it was significantly upregulated in metastatic lesions in lymph nodes compared to matched primary tumors. Increased expression of CCDC102B promoted breast cancer metastasis in vitro and in vivo. Additionally, high expression of CCDC102B was correlated with poor clinical outcomes in breast cancer patients. We further identified that CCDC102B was stabilized by the loss of RACK1, a protein negatively correlated with breast cancer metastasis. Mechanistically, we found that RACK1 promoted CCDC102B lysosomal degradation by mediating chaperone-mediated autophagy (CMA). The aggressive behavior of CCDC102B in breast cancer cells could be reversed by the expression of RACK1. Moreover, CCDC102B was correlated with the significant enrichment of NF-κB pathway components. Overexpressing CCDC102B led to less interaction between RACK1 and IKKa. Thus, CCDC102B positively regulates the NF−κB pathway by interacting with RACK1.

Conclusion

Taken together, our findings uncover a novel role of CCDC102B in breast cancer metastasis. CCDC102B serves as a potential metastasis promoter by regulating the activation of the NF-κB pathway and can be degraded by RACK1 via CMA.

The Prognoses of Young Women With Breast Cancer (≤35 years) With Different Surgical Options: A Propensity Score Matching Retrospective Cohort Study

Background

Compared with older patients, young women with breast cancer (YWBCs) have a poorer prognosis and a higher risk of recurrence. Ages ≤35 years are independent risk factors for local recurrence of breast cancer. Surgery is the most important local treatment for YWBC, and there is still a lack of prospective studies comparing surgical options for recurrence and survival. We retrospectively compared the effects of surgical options on disease-free survival (DFS) and overall survival (OS) of YWBC at Fudan University Shanghai Cancer Center (FUSCC).

Methods

YWBCs (age ≤35 years) who underwent surgery at FUSCC between 2008 and 2016 were retrospectively analyzed and divided into three groups according to surgical options: 1) breast-conserving surgery (BCS), 2) mastectomy alone (M), and 3) mastectomy with reconstruction (RECON). The DFS and OS outcome rates from the three surgical options were compared using the Kaplan–Meier method and Cox regression model. Propensity score matching (PSM) was also used to balance the baseline characteristics to eliminate selection bias.

Results

A total of 1,520 YWBCs were enrolled with a median follow-up of 5.1 years, including 524 patients (34.5%) who underwent BCS, 676 patients (44.5%) who underwent M, and 320 patients (21.1%) who underwent RECON. The 5-year DFS rates were 96%, 87%, and 93%, respectively (P < 0.001); the 5-year OS rates were 98%, 94%, and 97%, respectively (P = 0.002). Multivariate Cox analysis showed that DFS and OS were significantly improved in patients undergoing BCS compared with those undergoing M, with hazard ratios (HR) of 0.448 (95% CI 0.276–0.728; P = 0.001) and 0.405 (95% CI 0.206–0.797, P = 0.009), respectively. After PSM, DFS and OS rates were significantly improved in patients undergoing BCS compared to patients undergoing M (DFS, P = 0.001; OS, P = 0.009); RECON was also improved compared to patients undergoing M in terms of DFS and OS, but the difference was not statistically significant (DFS, P = 0.164; OS, P = 0.130).

Conclusions

The surgical options were independent factors affecting DFS and OS in YWBC, and the DFS and OS rates were significantly improved in the BCS group compared to those in the M group. BCS is preferred for early YWBC, and RECON is the best option for remodeling the body images of YWBC who do not have breast-conserving conditions.

Development and Validation of a Robust Ferroptosis-Related Gene Panel for Breast Cancer Disease-Specific Survival

Background: New biomarker combinations have been increasingly developed to improve the precision of current diagnostic and therapeutic modalities. Recently, researchers have found that tumor cells are more vulnerable to ferroptosis. Furthermore, ferroptosis-related genes (FRG) are promising therapeutic targets in breast cancer patients. Therefore, this study aimed to identify FRG that could predict disease-specific survival (DSS) in breast cancer patients. Methods: Gene expression matrix and clinical data were downloaded from public databases. We included 960, 1,900, and 234 patients from the TCGA, METABRIC, and GSE3494 cohorts, respectively. Data for FRG were downloaded from the FerrDb website. Differential expression of FRG was analyzed by comparing the tumors with adjacent normal tissues. Univariate Cox analysis of DSS was performed to identify prognostic FRG. The TCGA-BRCA cohort was used to generate a nine-gene panel with the LASSO cox regression. The METABRIC and GSE3494 cohorts were used to validate the panel. The panel's median cut-off value was used to divide the patients into high- or low-risk subgroups. Analyses of immune microenvironment, functional pathways, and clinical correlation were conducted via GO and KEGG analyses to determine the differences between the two subgroups. Results: The DSS of the low-risk subgroup was longer than that of the high-risk subgroup. The panel's predictive ability was confirmed by ROC curves (TCGA cohort AUC values were 0.806, 0.695, and 0.669 for 2, 3, and 5 years respectively, and the METABRIC cohort AUC values were 0.706, 0.734, and 0.7, respectively for the same periods). The panel was an independent DSS prognostic indicator in the Cox regression analyses. (TCGA cohort: HR = 3.51, 95% CI = 1.792-6.875, p < 0.001; METABRIC cohort: HR = 1.76, 95% CI = 1.283-2.413, p < 0.001). Immune-related pathways were enriched in the high-risk subgroup. The two subgroups that were stratified by the nine-gene panel were also associated with histology type, tumor grade, TNM stage, and Her2-positive and TNBC subtypes. The patients in the high-risk subgroup, whose CTLA4 and PD-1 statuses were both positive or negative, demonstrated a substantial clinical benefit from combination therapy with anti-CTLA4 and anti-PD-1. Conclusion: The new gene panel consisting of nine FRG may be used to assess the prognosis and immune status of patients with breast cancer. A precise therapeutic approach can also be possible with risk stratification.

Clinical and Genetic Predictive Models for the Prediction of Pathological Complete Response to Optimize the Effectiveness for Trastuzumab Based Chemotherapy

Background

Trastuzumab shows excellent benefits for HER2+ breast cancer patients, although 20% treated remain unresponsive. We conducted a retrospective cohort study to optimize neoadjuvant chemotherapy and trastuzumab treatment in HER2+ breast cancer patients.

Methods

Six hundred patients were analyzed to identify clinical characteristics of those not achieving a pathological complete response (pCR) to develop a clinical predictive model. Available RNA sequence data was also reviewed to develop a genetic model for pCR.

Results

The pCR rate was 39.8% and pCR was associated with superior disease free survival and overall survival. ER negativity and PR negativity, higher HER2 IHC scores, higher Ki-67, and trastuzumab use were associated with improved pCR. Weekly paclitaxel and carboplatin had the highest pCR rate (46.70%) and the anthracycline+taxanes regimen had the lowest rate (11.11%). Four published GEO datasets were analyzed and a 10-gene model and immune signature for pCR were developed. Non-pCR patients were ER⁺PR⁺ and had a lower immune signature and gene model score. Hormone receptor status and immune signatures were independent predictive factors of pCR.

Conclusion

Hormone receptor status and a 10-gene model could predict pCR independently and may be applied for patient selection and drug effectiveness optimization.

[A study of LEF1 protein expression in diagnosis and differential diagnosis of lymphoblastic lymphoma/acute lymphoblastic leukemia]

Objective: To evaluate the expression of LEF1 protein in lymphoblastic lymphoma/acute lymphoblastic leukemia (LBL/ALL) and small B-cell lymphomas, and its value in pathologic diagnosis and differential diagnosis of LBL/ALL. Methods: 53 cases of LBL/ALL were collected at shanghai Tongji Hospital from January 2012 to December 2019. The protein expression of LEF1 and TdT was detected by immunohistochemistry in 53 paraffin-embedded tissue samples of LBL/ALL. The specificity and sensitivity of LEF1 and TdT in the diagnosis of LBL/ALL were compared. The expression of LEF1 protein in 77 cases of small B-cell lymphomas including chronic lymphocytic leukemia/small lymphoid lymphoma (CLL/SLL), follicular lymphoma, mantle cell lymphoma, marginal zone lymphoma and Waldenstrom's macroglobulinemia/lymphoplasmacytic lymphoma was studied. The correlation between LEF1 expression and overall survival (OS) and progression-free survival (PFS) was performed by univariate analysis. Results: The expression of LEF1 in LBL/ALL was 100% (53/53), the median value was 90%; the expression of TdT was 84.9% (T-LBL/ALL 78.1%, B-LBL/ALL 95.2%), the median value was 80%; the expression rate and median value of LEF1 and TdT were significantly different (P=0.008 and 0.001 respectively). The expression of LEF1 in CLL/SLL was 14/18, the median value was 45%; LEF1 was not expressed in follicular lymphoma (0/16), mantle cell lymphoma (0/16), marginal zone lymphoma (0/19), and Waldenstrom's macroglobulinemia/lymphoplasmacytic lymphoma (0/8). LEF1 expression was significantly different between B-LBL/ALL and small B-cell lymphomas. The median follow-up time of LBL/ALL cases in this group was 16 months. There was no statistical difference between LEF1 expression and the OS and PFS in LBL/ALL patients. Conclusions: Immunohistochemical staining of LEF1 has high sensitivity and good specificity in the diagnosis of LBL/ALL, and its combination with TdT can improve the diagnostic rate of LBL/ALL.

A pan-cancer analysis of HER2 index revealed transcriptional pattern for precise selection of HER2-targeted therapy

Background

The prevalence of HER2 alterations in pan-cancer indicates a broader range of application of HER2-targeted therapies; however, biomarkers for such therapies are still insufficient and limited to breast cancer and gastric cancer.

Methods

Using multi-omics data from The Cancer Genome Atlas (TCGA), the landscape of HER2 alterations was exhibited across 33 tumor types. A HER2 index was constructed using one-class logistic regression (OCLR). With the predictive value validated in GEO cohorts and pan-cancer cell lines, the index was then applied to evaluate the HER2-enriched expression pattern across TCGA pan-cancer types.

Findings

Increased HER2 somatic copy number alterations (SCNAs) could be divided into two patterns, focal- or arm-level. The expression-based HER2 index successfully distinguished the HER2-enriched subtype from the others and provided a stable and superior performance in predicting the response to HER2-targeted therapies both in breast tumor tissue and pan-cancer cell lines. With frequencies varying from 12.0% to 0.9%, tumors including head and neck squamous tumors, gastrointestinal tumors, bladder cancer, lung cancer and uterine tumors exhibited high HER2 indices together with HER2 amplification or overexpression, which may be more suitable for HER2-targeted therapies. The BLCA.3 and HNSC.Basal were the most distinguishable subtypes within bladder cancer and head and neck cancer respectively by HER2 index, implying their potential benefits from HER2-targeted therapies.

Interpretation

As a pan-cancer predictive biomarker of HER2-targeted therapies, the HER2 index could help identify potential candidates for such treatment in multiple tumor types by combining with HER2 multi-omics features. The discoveries of our study highlight the importance of incorporating transcriptional pattern into the assessment of HER2 status for better patient selection.

Funding

The National Key Research and Development Program of China; Clinical Research and Cultivation Project of Shanghai ShenKang Hospital Development Center.

Autologous tissue reconstruction after mastectomy-A cross-sectional survey of 110 hospitals in China

BACKGROUND

Autologous reconstruction after mastectomy became more and more popular, so this study aimed to obtain up-to-date and comprehensive data on autologous reconstruction in China.

METHODS

An electronic questionnaire was sent to 110 hospitals, which were chosen depending on geographical distribution and hospital types. The questionnaire investigated the demographics, characteristics, breast cancer treatment and reconstruction situation of these hospitals through different modules. We only focused on the autologous breast reconstruction module data.

RESULTS

96 hospitals have performed breast reconstruction surgery. The proportion of the hospital performing latissimus dorsi flap (LDF, N = 91), pedicle transverse rectus abdominis myocutaneous flap (pTRAM, N = 62), free abdominal flap (N = 43) and other kinds of flap decreased in sequence. Of the overall reconstruction cases, only 34.3% were autologous reconstruction and LDF was still the most popular option for autologous reconstruction. Related factors of hospital performing different procedures included years of performing breast reconstruction, breast surgical volume, and establishment of an independent plastic surgery department. Compared with LDF, abdominal breast reconstruction was associated with a higher flap necrosis rate.

CONCLUSIONS

This cross-sectional survey offers real-life autologous reconstruction information on a large population and covers the national surgical landscape in China. Autologous reconstruction is still an important part of breast reconstruction. Nevertheless, its low proportion and lower proportion of abdominal flap reconstruction in each institution, demonstrates that special training should be developed for breast surgeons and multidisciplinary cooperation would be promoted in the future.

Abstract P1-05-08: LINC00926 interacts with HNRNPC and suppress metastasis in breast cancer

Background: The recent discovery of the long noncoding RNA genes has dramatically altered our understanding of cancer genetics. Breast cancer is a collection of diseases with variable molecular underpinnings that modulate therapeutic responses, disease free intervals, and long-term survival of patients. In this study, we report the identification of a lncRNA signature associated with metastasis of breast cancer.

Methods: LINC00926 was identified by microarray and validated by real-time PCR. Survival analysis was evaluated using the Kaplan-Meier method and assessed using the log-rank test. In vitro assays were preformed to explore the biological effects of LINC00926 in BC cells. The interaction of LINC00926 with HNRNPC was identified by RNA pull-down and RNA immunoprecipitation.

Results: We assessed the expression of LINC00926 in 293 invasive breast cancer tumors in Fudan University Shanghai Cancer Center (FUSCC), Kaplan-Meier analysis revealed that the high expression level of LINC00926 was significantly associated with good overall survival (OS) (P = 0.009) and disease-free survival (DFS) (P = 0.007). Low expression of LINC00926 was also associated with poor overall survival in TCGA database. Cox proportional hazards regression analysis further demonstrated that high LINC00926 expression level was an independent prognostic factor for overall survival (HR: 0.37; 95% CI: 0.16-0.84; P = 0.018) and DFS (HR: 0.48; 95% CI: 0.24-0.98; P = 0.045). These results suggested that LINC00926 might be a potential tumor-suppressor lncRNA in breast cancer. LINC00926 was mainly located in the cell nucleus. Overexpression of full-length LINC00926 significantly inhibited breast cancer proliferation, invasion and migration in vitro. Knockdown transcriptional activation of LINC00926 promotes the ability of tumor proliferation and metastasis. Via RNA pull-down assay and mass spectrometry, HNRNPC was found to interact with LINC00926. HNRNPC repression is well known to induce alternative splicing. Therefore, such compensating machinery may monitor the RNA post-transcriptional processing and block dsRNA generation. This hypothesis certainly worths further investigation.

Conclusion: Our study revealed a correlation between LINC00926 and metastases in breast cancer. High level of LINC00926 was associated with better metastasis-free survival. The changed metastasis phenotype may be mediated by the interaction of LINC00926 and HNRNPC via meditation of post-transcriptional processing in breast cancer cells. Therefore, LINC00926 may represent a potential predictive biomarker for inhibiting breast cancer invasion-metastasis cascade.

Citation Format: Jianjing Hou, Bingqiu Xiu, Weiru Ji, Qi Zhang, Rong Guo, Yayun Chi, Jiong Wu. LINC00926 interacts with HNRNPC and suppress metastasis in breast cancer [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 P1-05-08.

LINC02273 drives breast cancer metastasis by epigenetically increasing AGR2 transcription

BACKGROUND

The majority of breast cancer patients die of metastasis rather than primary tumors, whereas the molecular mechanisms orchestrating cancer metastasis remains poorly understood. Long noncoding RNAs (lncRNA) have been shown to regulate cancer occurrence and progression. However, the lncRNAs that drive metastasis in cancer patients and their underlying mechanisms are still largely unknown.

METHODS

lncRNAs highly expressed in metastatic lymph nodes were identified by microarray. Survival analysis were made by Kaplan-Meier method. Cell proliferation, migration, and invasion assay was performed to confirm the phenotype of LINC02273. Tail vein model and mammary fat pad model were used for in vivo study. RNA pull-down and RIP assay were used to confirm the interaction of hnRNPL and LINC02273. Chromatin isolation by RNA purification followed by sequencing (ChIRP-seq), RNA-seq, ChIP-seq, and luciferase reporter assay reveal hnRNPL-LINC02273 regulates AGR2. Antisense oligonucleotides were used for in vivo treatment.

RESULTS

We identified a novel long noncoding RNA LINC02273, whose expression was significantly elevated in metastatic lesions compared to the primary tumors, by genetic screen of matched tumor samples. Increased LINC02273 promoted breast cancer metastasis in vitro and in vivo. We further showed that LINC02273 was stabilized by hnRNPL, a protein increased in metastatic lesions, in breast cancer cells. Mechanistically, hnRNPL-LINC02273 formed a complex which activated AGR2 transcription and promoted cancer metastasis. The recruitment of hnRNPL-LINC02273 complex to AGR2 promoter region epigenetically upregulated AGR2 by augmenting local H3K4me3 and H3K27ac levels. Combination of AGR2 and LINC02273 was an independent prognostic factor for predicting breast cancer patient survival. Moreover, our data revealed that LINC02273-targeting antisense oligonucleotides (ASO) substantially inhibited breast cancer metastasis in vivo.

CONCLUSIONS

Our findings uncover a key role of LINC02273-hnRNPL-AGR2 axis in breast cancer metastasis and provide potential novel therapeutic targets for metastatic breast cancer intervention.

Axillary evaluation is not warranted in patients preoperatively diagnosed with ductal carcinoma in situ by core needle biopsy

Background

Patients diagnosed with ductal carcinoma in situ (DCIS) by core needle biopsy (CNB) have a great chance of upstaging to invasive cancer. Positive axillary status can be found in these patients. This study sought to identify clinicopathological factors associated with upstaging and axillary metastasis in patients preoperatively diagnosed with DCIS by CNB.

Materials and Methods

This study identified 604 patients (cT1‐3N0M0) with preoperative diagnosis of pure DCIS by CNB who had undergone axillary evaluation from August 2006 to December 2015 at Fudan University Shanghai Cancer Center (FUSCC). Predictors of upstaging and axillary lymph nodes metastasis were analyzed, respectively.

Results

Of all 604 patients, 121 (20.03%) and 193 (31.95%) patients were upstaged to DCIS with microinvasion (DCISM) and invasive breast cancer (IBC). Positive axillary lymph nodes were identified in 41 (6.79%) patients. Predictors of upstaging included tumor size on ultrasonography (>2 cm) (OR 1.786, P = .002) and ER+HER2+ status (OR 1.874, P = .022) in multivariate analysis. Factors associated with axillary lymph nodes metastasis included tumor size on pathology (OR 2.336, P = .038) and number of lesions (OR 3.354, P = .039) in multivariate analysis. In addition, upstaging on final pathology had a significant influence on axillary lymph nodes status (P < .001).

Conclusion

Axillary evaluation was recommended in patients with larger tumor size (>2 cm), multifocal lesions or ER+HER2+ status. Despite of a 51.98% upstaging rate, the rate of axillary metastasis in these patients was relatively low, supporting the omission of axillary evaluation in selected patients with low risk of upstaging or axillary metastasis.

Applications of rib sparing technique in internal mammary vessels exposure of abdominal free flap breast reconstructions: a 12-year single-center experience of 215 cases

Background

Internal mammary vessels (IMVs) are widely used recipient vessels in abdominal free flap breast reconstructions. Rib sparing technique is an alternative method with less damage in IMVs exposure. This study aims to investigate the factors influencing the selection of IMVs, as well as analyze the applicability and related factors of rib sparing technique in abdominal breast reconstruction.

Methods

Medical records of 215 patients who underwent abdominal free flap reconstruction from November 2006 to December 2017 in Fudan University Shanghai Cancer Center (FUSCC) were analyzed. Intercostal space (ICS) was measured from preoperative chest computed tomography scan. Factors influencing the choice of recipient vessels and rib sparing were analyzed. Surgery time, hospitalization and complications were assessed.

Results

Among all 218 flaps, 172 flaps used IMVs as the recipient vessels while 46 used other vessels. patients with immediate reconstruction (P=0.005) and axillary lymph nodes dissection (ALND) (P<0.001) were less likely to use IMVs. Patients' body mass index (BMI) and radiotherapy history showed no statistically significant differences between the two groups (P=0.338 and 0.811). In IMVs group, 62% cases used rib sparing technique. Compared with rib resection group, patients with rib sparing were taller (P=0.047) and with a wider ICS (2.65±0.54 vs. 2.25±0.38 cm, P<0.001). Rib sparing group had a shorter surgery and postoperative hospitalization time, as well as a lower complication rate, but the differences were not statistically significant (P=0.120, 0.450 and 0.612).

Conclusions

IMVs were used more frequently as the recipient vessels in abdominal free flap breast reconstructions, especially when axillary operation was not performed at the same time. Rib sparing technique had the potential to decrease surgery time, hospitalization days and complications rate. It could be applied in most of the patients with IMVs exposure, particularly in taller patients and patients with a wider ICS. Preoperative chest computed tomography scan can be used to assess the ICS width to provide operational suggestions.

CapG promotes resistance to paclitaxel in breast cancer through transactivation of PIK3R1/P50

Background: Chemotherapy resistance is a major problem in breast cancer treatment and a leading cause of mortality in breast cancer patients. Biomarkers for chemotherapy resistance is under investigation.

Methods: Paclitaxel resistant cells were established and subjected to RNA sequencing. Analysis combined with two additional RNA-seq datasets was conducted. CapG expression in patients with adjuvant chemotherapy was studied in breast cancer resection specimens using IHC and related to pathological response and disease-free survival. Paclitaxel resistance was assessed by half-maximal inhibitory concentrations (IC50) and a mouse xenograft model.

Results: Increased expression of actin-binding protein CapG strongly correlated with the resistance to paclitaxel chemotherapy and decreased probability to achieve pathological complete response in breast cancer patients. Overexpressing CapG significantly enhanced paclitaxel resistance in breast cancer cells and xenograft tumors. High CapG level also significantly correlated with shorter relapse-free survival as well as hyper-activation of PI3K/Akt signaling in breast cancer patients. Mechanistically, CapG enhanced PIK3R1 expression which led to increased PI3K/Akt activation. Unexpectedly, CapG was found to bind to the variant-specific promoter of PIK3R1/P50 and directly enhance its transcription. We also identified p300/CBP as a transcriptional coregulator of CapG, which is recruited to PIK3R1 promoter through interaction with CapG, thereby increasing PIK3R1/P50 transcription by enhancing histone H3K27 acetylation. Consistently, inhibiting p300/CBP substantially decreased CapG-dependent upregulation of PIK3R1/P50 and subsequent PI3K/Akt activation, resulting in increased sensitivity to paclitaxel treatment in breast cancer cells.

Conclusion: High CapG levels may predict poor paclitaxel response in breast cancer patients. Targeting CapG-mediated hyperactivation of PI3K/Akt pathway may mitigate resistance to chemotherapy in breast cancer.

Current practice and barriers of mesh-assisted implant-based breast reconstruction in China: A nationwide cross-sectional survey of 110 hospitals

BACKGROUND

The current National Practice Questionnaire of implant-based breast reconstruction (IBBR) (NPQi) was to assess the clinical practice of mesh-assisted IBBR in China.

METHODS

A questionnaire was mailed to 110 hospitals in China, which have more than 200 breast cancer operations performed in 2017. The survey mainly included questions on the type and timing of IBBR, questions about the use of TiLOOP® Bra and acellular dermal matrix (ADM) and the complications of IBBR.

RESULTS

IBBR was routinely carried out in 86.36% (95/110) hospitals. IBBR was the most frequently-used (65.7%, 4,296/6,534) BR after mastectomy with a median of 24 cases (IQR 7.5-65) in each hospital. TiLOOP® Bra and ADM were available in 49.5% and 33.7% hospitals, respectively. Hospitals with ADM offered were more likely to located in economically developed regions (65.6%), when compared with hospitals without any mesh offered (14/35, 40.0%, P = 0.036) and with only TiLOOP® Bra offered (16/28, 57.1%, P = 0.032). The surgery volume was largely variated from hospitals without any mesh offered (median 380 cases, IQR 304-550), with only TiLOOP® Bra offered (median 790 cases, IQR 439-1096, P = 0.001) and with ADM offered (median 797 cases, IQR 497-1528, P < 0.001). Higher proportion of one-stage mesh-augmented direct-to-implant BR and lower proportion of autologous BR were observed in hospitals with mesh offered. The reported major complications were similar between hospitals with or without mesh offered.

CONCLUSIONS

The NPQi has provided a valuable insight into the current practice of IBBR and mesh used in China. The introduction of mesh-assisted techniques has revolutionized the clinical practice.

High expression of Linc00959 predicts poor prognosis in breast cancer

Background

Accumulating studies have focused on the oncogenic roles of the newly identified lncRNAs in human cancers. The aim of this study was to examine the expression pattern of Linc00959 in BC and to evaluate its biological role and clinical significance in prediction of prognosis.

Methods

Expression of Linc00959 was detected in 290 BC tissues by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). We analyzed the relationship between Linc00959 expression and clinic pathological features of BC patients. The correlation was calculated by SPSS software.

Results

Our results revealed that Linc00959 expression was correlated with ER status (p = 0.005), PR status (p = 0.036), Ki67 (p = 0.025) and HER2 status (p = 0.009). The Kaplan–Meier survival curves indicated that the overall survival (OS) (p = 0.022) and relapse-free survival (RFS) (p = 0.002) were significantly poor in high Linc00959 expression BC patients (p = 0.023). Furthermore, the survival analysis by Cox regression showed that Linc00959 served as an independent prognostic marker in breast cancer (p = 0.004).

Conclusion

Our studies indicate that Linc00959 is significantly associated with poor prognosis and may represent a new marker of prognosis in breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0748-7) contains supplementary material, which is available to authorized users.

Abstract P5-16-08: Applications of rib sparing technique in internal mammary vessels exposure of abdominal free flap breast reconstructions

Background:

Internal mammary vessels (IMVs) are widely used recipient vessels in abdominal free flaps breast reconstructions. Exposure of IMVs usually needs to resect a segment of costal cartilage or rib during the operations. The rib sparing technique is an alternative method with less damage. This study aims to analysis the applicability and advantages of rib sparing technique of IMVs exposure in breast reconstruction.

Methods:

medical records of 215 patients who underwent abdominal free flap reconstruction from November 2006 to December 2017 were analyzed. The factors influencing the choice of vessels and rib sparing were analyzed. The outcomes of rib sparing were assessed. Intercostal space (ICS) width and other related data were measured by the preoperative thin slice chest computed tomography (CT) scan images.

Results:

Among all 215 patients with 218 flaps, 172 flaps used IMVs as the recipient vessels while 13 used thoracodorsalvessels and 33 used subscapular vessels. The proportion of IMVs as recipient vessels showed a rising trend in general and remained over 90% for the last three years in our center. Patients with immediate reconstruction (p=0.005) and axillary lymph nodes dissection(ALND) (p&lt;0.001) were less likely to use IMVs, both in univariate and multivariate logistic regression analysis. Patients' BMI and radiotherapy history showed no statistically significant differences between the IMVs group and the other vessels group (p=0.338 and 0.811). The rib sparing rate in IMVs exposure increased yearly and exceeded 40% in 2013, now it maintained more than 60% during the recent 3 years. Additionally, among the patients who received rib sparing IMVs exposure in 2017, the mean ICS width was relatively smaller than that in 2013 (2.54cm V.S 2.93cm, p=0.124). Compared with rib resection group, patients with rib sparing were higher (163.57 ± 4.44 cm vs. 161.83 ± 4.30 cm, p=0.047) and with a wider ICS (2.65 ± 0.54 cm vs. 2.25± 0.38 cm, p&lt;0.01), while the depth from the surface of the pectoralis major muscle to the IMVs and distance between the parasternal line and IMVs had no difference between the two groups. Rib sparing group has a shorter surgery and hospitalization time, as well as a lower severe complication rate, but the differences were not statistically significant (p= 0.120, 0.450 and 0.296).

Conclusion:

IMVs were used more frequently as the recipient vessels in abdominal free flap breast reconstructions, especially when axillary operation was not carried out at the same time. Rib sparing technique had the potential to decrease surgery time and hospitalization days, as well as the severe complications rate. It could be used in most of patients received free flap reconstruction when IMVs were used, particularly in higher patients and patients with a wider ICS. Preoperative slice chest CT scan can be used to measure the ICS width to provide suggestions for dealing with the ribs.

Citation Format: Zhang Q, Xiao Q, Guo R, Wu J, Gu Y, Xiu B. Applications of rib sparing technique in internal mammary vessels exposure of abdominal free flap breast reconstructions [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 P5-16-08.

Abstract P6-05-08: LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer

The prognosis of breast cancer patients with metastasis is still poor even improved by current treatment modalities. Unveiling new biomarkers and molecular mechanisms that underlie metastasis are of vital importance for the treatment of breast cancer. The recent discovery of long noncoding RNAs (lncRNAs) has gained widespread attention. To identify critical lncRNAs that contributed to breast cancer metastasis, we profiled their expression in 5 pairs of primary tumors and lymph nodes metastasis loci by HTA2.0 microarray. LINC02273 is significantly upregulated in metastasis loci and its high expression is associated with poor diseases free survival in a validation set of 254 patients. LINC02273 was mainly located in the cell nucleus . RACE-PCR showed two isoforms and the longest one was the most abundant isoform in breast cancer. Through transwell assay, 3D spheroid invasion assay and mice xenograft metastasis model, we found that LINC02273 promoted breast cancer cell migration, invasion and metastasis. Via mass spectrometry, hnRNPL was found to interact with LINC02273 to enhance its stability, which was further confirmed by Actinomycin D inhibition assay and luciferase reporter assay. Furthermore, ChIRP-seq and ChIP-seq showed that LINC02273 stimulated oncogene AGR2 expression by directly binding to the AGR2 promoter region and increasing H3K27ac modification. Triplex formation assay was performed for verification. We demonstrated that the expression level and oncogenic ability of AGR2 were regulated by hnRNPL through LINC02273. Clinical data and mouse xenograft tumors also revealed the positive correlation of AGR2 and LINC02273. In conclusion, LINC02273, which is stabilized by hnRNPL can promote breast cancer metastasis through upregulation of AGR2 and may serve as a prognostic biomarker for breast cancer.

Citation Format: Xiu B, Chi Y, Ji W, Zhang Q, Wu J. LINC02273 interacts with hnRNPL and promotes metastasis through directly activating AGR2 in breast cancer [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 P6-05-08.

Abstract P5-03-13: ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy

Although anti-HER2/neu antibody therapy combined with chemotherapy has achieved an outstanding effect, many patients with HER2-positive breast cancer still succumb due to therapeutic resistance. Understanding the mechanisms of therapeutic resistance is of vital importance. In this study, core needle biopsy tissue from HER2-positive patients was collected before neoadjuvant chemotherapy. Differentially expressed RNAs between pCR and non-pCR group have been identified through RNA-seq. Here we found that ERVMER34, an endogenous retroviral envelope protein was significantly inhibited in non-pCR group compared to pCR group. High ERVMER34 expression was associated with good overall survival both in TCGA database and our own patients cohort. Further study showed that ERVMER34 could be glycosylated and secreted to cell supernatant. The IC50 of paclitaxel and trastuzumab in HER2 positive breast cancer cells was decreased by ectopic overexpression of ERVMER34. Furthermore, RNA-seq, FACS assay and western blot revealed that ERVMER34 could promote cell apoptosis and sensitize therapy response through inhibiting mTOR pathway in HER2 positive breast cancer cells. Via mass spectrometry, TRIM21, an E3 ligase was found to interact with ERVMER34 and promoted its ubiquitination degradation. Taken together, these data suggest that ERVMER34 may severve as a novel biomarker to predict therapy response in HER2 positive breast cancer.

Citation Format: Chi Y, Ji W, Xiu B, Zhang Q, Wu J. ERVMER34 sensitizes the response of HER2 positive breast cancer to neoadjuvant therapy [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 P5-03-13.

Factors associated with upstaging in patients preoperatively diagnosed with ductal carcinoma in situ by core needle biopsy

Objective

Patients preoperatively diagnosed with ductal carcinoma in situ (DCIS) by core needle biopsy (CNB) exhibit a significant risk for upstaging on final pathology, which leads to major concerns of whether axillary staging is required at the primary operation. The present study aimed to identify clinicopathological factors associated with upstaging in patients preoperatively diagnosed with DCIS by CNB.

Methods

The present study enrolled 604 patients (cN0M0) with a preoperative diagnosis of pure DCIS by CNB, who underwent axillary staging between August 2006 and December 2015, at Fudan University Shanghai Cancer Center (Shanghai, China). Predictive factors of upstaging were analyzed retrospectively.

Results

Of the 604 patients, 20.03% (n = 121) and 31.95% (n = 193) were upstaged to DCIS with microinvasion (DCISM) and invasive breast cancer (IBC) on final pathology, respectively. Larger tumor size on ultrasonography (> 2 cm) was independently associated with upstaging [odds ratio (OR) 1.558,P = 0.014]. Additionally, patients in lower breast imaging reporting and data system (BI-RADS) categories were less likely to be upstaged (4B vs. 5: OR 0.435, P = 0.002; 4C vs. 5: OR 0.502, P = 0.001). Overall, axillary metastasis occurred in 6.79% (n = 41) of patients. Among patients with axillary metastasis, 1.38% (4/290), 3.31% (4/121) and 17.10% (33/193) were in the DCIS, DCISM, and IBC groups, respectively.

Conclusions

For patients initially diagnosed with DCIS by CNB, larger tumor size on ultrasonography (> 2 cm) and higher BI-RADS category were independent predictive factors of upstaging on final pathology. Thus, axillary staging in patients with smaller tumor sizes and lower BI-RADS category may be omitted, with little downstream risk for upstaging.

C-terminus of heat shock protein 60 can activate macrophages by lectin-like oxidized low-density lipoprotein receptor 1

Immune responses against antigens generally require an efficient activation of antigen-presenting cells (APCs). Currently, the targeting of vaccine antigens to APCs has emerged as a promising strategy for boosting vaccine immunogenicity. Here, we reported that the C-terminus of heat shock protein 60 (HSP60C) can activate mouse peritoneal macrophages to secret a series of cytokines, and phosphorylation of p38 mitogen-activated protein kinase (MAPK) and NF-κB p65 was involved in the pathway. We showed that the activation effect of HSP60C on macrophages was independent of toll-like receptor (TLR) 4 and the TLR-associated myeloide differentiation factor 88 (MyD88). Knockdown of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) reduced the activation of HSP60C-induced macrophage p38 MAPK, NF-κB p65 and cytokine secretion to some extent. Finally, we found that HSP60C up-regulated the expression of LOX-1 on macrophages and ovalbumin (OVA) model antigen fused with HSP60C markedly enhanced OVA-specific IgG responses. Thus, our results unravel a novel LOX-1-dependent pathway by which HSP60C can effectively activate macrophages and APCs targeting based on LOX-1 interaction is a promising approach to improve vaccines.

CAPG enhances breast cancer metastasis by competing with PRMT5 to modulate STC-1 transcription

Macrophage-capping protein (CAPG) has been shown to promote cancer cell metastasis, although the mechanism remains poorly understood.

Methods: Breast cancer (BC) tissue microarray was used to test the role of CAPG in the prognosis of BC patients. Xenograft mice model was used to validate the metastasis promotion role of CAPG in vivo. Gene expression array, chromatin immunoprecipitation and luciferase report assay were performed to search for the target genes of CAPG. Protein immunoprecipitation, MS/MS analysis, tissue microarray and histone methyltransferase assay were used to explore the mechanism of CAPG regulating stanniocalcin 1 (STC-1) transcription.

Results: We demonstrate a novel mechanism by which CAPG enhances BC metastasis via promoting the transcription of the pro-metastatic gene STC-1, contributing to increased metastasis in BC. Mechanistically, CAPG competes with the transcriptional repressor arginine methyltransferase 5 (PRMT5) for binding to the STC-1 promoter, leading to reduced histone H4R3 methylation and enhanced STC-1 transcription. Our study also indicates that both CAPG and PRMT5 are independent prognostic factors for BC patient survival. High CAPG level is associated with poor survival, while high PRMT5 expression favors a better prognosis in BC patients.

Conclusion: Our findings identify a novel role of CAPG in the promotion of BC metastasis by epigenetically enhancing STC-1 transcription.

Abstract P5-07-05: LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients

Background

Long non-coding RNAs (lncRNAs) have been proved to play an essential role in cancer metastasis. The accuracy of intraoperative assessment of lymph nodes metastasis need to be improved. In this study, we aimed to define the lncRNA biomarker ectopic expressed in breast cancer patients' metastatic lymph nodes, and to explore the potential molecular mechanisms.

Experimental Design

RNA-seq analyses in 3 paired breast cancer patients' primary tumor and metastatic lymph node was used as training set to determine differentially expressed lncRNAs that may be associated with lymph node metastasis. The other 40 patients were analyzed as validation set to test the accuracy of lncRNAs identification by quantitative real-time PCR. The correlation between LOC283299 expression level and prognosis in other 282 breast cancer patients was confirmed. In parallel, in vitro and in vivo analyses were carried out to determine the potential mechanisms of LncRNA-dependent lymph node metastases and prognosis.

Results

RNA-seq analyses in the training set revealed significant correlation between high expression level of LOC283299 and lower lymph node metastasis potential in breast cancer patients. We further validated that the expression level of LOC283299 was significantly higher in tumor primary tissue than that in paired metastatic lymph node (P=0.0245), and higher LOC283299 expression level was markedly associated with good metastasis-free survival in breast cancer patients (P=0.04). In breast cancer cell lines, CRISPR-on overexpression of LOC283299 inhibited proliferation, migration, invasion, and metastases both in vivo and in vitro. shRNA knockdown LOC283299 promotes the ability of tumor proliferation and metastasis. The molecular mechanisms by which LOC283299 as metastasis-suppressing lncRNAs regulates recurrence and metastasis may involve regulation of epithelial to mesenchymal transition (EMT), cellular invasion and microenvironment in breast cancer cells.

Conclusion

Our study revealed a strong correlation between LOC283299 expression and lymph node metastases in breast cancers. High level of LOC283299 was associated with better metastasis-free survival. The changed metastasis phenotype may be mediated by the interaction of LOC283299 and breast cancer cells. Therefore, LOC283299 may represent a potential predictive biomarker for early lymph node metastasis in breast cancer.

Citation Format: Guo R, Xue J, Su Y, Xiu B, Ji W, Chi Y, Wu J. LOC283299 suppress the lymphnode metastatic cascade in breast cancer patients [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 P5-07-05.

Stereotactic biopsy for intracranial space-occupying lesions: clinical analysis of 550 cases

OBJECT

To investigate the role of stereotactic biopsy in planning the optimal management of intracranial space-occupying lesions.

PATIENTS AND METHODS

Between December 1989 and December 1999, stereotactic biopsy was performed in 550 patients with intracranial mass lesions that were deep-seated or located in the functional area. There were 340 males and 210 females, and their ages ranged from 4 to 75 years. All the procedures were done under local anesthesia with a Leksell stereotactic system. A CT scan was used to determine the coordinates in the first 420 cases and the Aero Tech Stereotactic Surgical Plan System in the subsequent 130 patients.

RESULTS

Brain tumors were diagnosed pathologically in 475 patients (86.4%), inflammatory process in 44 (8.0%), other lesions in 12 (2.2%) and no conclusive diagnosis was found in 19 (3.4%). The overall positive rate of biopsy was 96.6%, and the positive rate for brain tumor was 86.4%. Intracranial hematomas after biopsy were found in 13 cases (2.4%). Seizures occurred during the operation in 7 cases (1.2%), and slight and transient neurological deficits were found in 23 cases (4.2%). There were no deaths or other serious complications.

CONCLUSIONS

The results suggest that the stereotactic biopsy is a reliable method to obtain histopathological diagnosis of intracranial mass lesions, and it is also of great help in selecting the appropriate management.