Metastatic Relapse Of Breast Cancer Research Articles

Abstract PO2-04-01: Predictors of exceptional response to first line HER2-targeted therapy for metastatic breast cancer

Abstract Background HER2-targeted therapies have transformed the trajectory of HER2-positive (HER2+) metastatic breast cancer (MBC), with a subgroup of responders remaining on first line (1L) therapy for many years (yrs). Despite these promising outcomes, the paradigm remains palliative, with some patients (pts) receiving therapy indefinitely. Opportunities to interrupt therapy are controversial and anecdotal in the setting of a limited understanding of long-term responders and lack of predictive biomarkers. Methods We identified prevalent pts with HER2+ MBC seen and consented at Dana-Farber Cancer Institute between 2010 and 2023, regardless of the original date of MBC diagnosis. Exceptional responders (ExRes) were pts without evidence of progressive disease (PD) 3 yrs from initiation of 1L therapy for MBC. Conventional responders (ConRes) were pts who experienced PD within 3 yrs of 1L treatment initiation. We compared clinicopathological characteristics and treatment patterns between ExRes and ConRes using Chi-square or Wilcoxon test. We analyzed median time to treatment switch due to PD (TTS-PD) – i.e., time from metastatic diagnosis to 1L treatment end due to PD - and overall survival, via the Kaplan-Meier method and with a landmark analysis at year 3 (Y3). Our primary aim was to identify predictors of exceptional response to 1L anti-HER2 therapy. Results Of 635 pts with HER2+ MBC, we identified 147 ExRes and 370 ConRes and excluded 118 pts due to follow up ≤ 3 yrs and no PD events. Median follow up was 7.1 yrs (IQR 5.5-11.0) for ExRes and 7.1 yrs (IQR 4.0-11.4) for ConRes. Median age at MBC diagnosis was 50.7 yrs (range 21.9-91.9) for ExRes and 49.8 yrs (26.9-82.3) for ConRes. ExRes presented more often with de novo MBC than ConRes (52.1 vs 30.6%, p< 0.0001). On metastatic samples, more ExRes than ConRes had HER2 3+ tumors by immunohistochemistry (IHC) (93.7 vs 81.0%, p=0.002), whereas the proportion of ER-positive disease was similar between the two groups (45.6 vs 53.4%, p=0.1). Most pts received (neo)adjuvant anti-HER2 agents in both groups (62.5 vs 72.7%, p=0.1). More ExRes than ConRes (55.8 vs 42.7% p=0.007) received 1L chemotherapy (CT) plus trastuzumab (H)/pertuzumab (P). Alternative 1L treatments were CT plus H (26.5 vs 25.7%), H +/- P +/- endocrine therapy (8.2 vs 10.5%), T-DM1 (2 vs 9.2%), tyrosine kinase inhibitors-based regimens (7.5 vs 10.8%). For pts with recurrent MBC, disease-free interval was longer for ExRes than ConRes (median 4.7 vs 3.4 yrs, p=0.01). Visceral involvement at MBC relapse was similar for ExRes and ConRes (78.2 vs 77.8%, p=0.9). Brain metastases at any timepoint were less frequent among ExRes than ConRes (42.9 vs 55.1%, p=0.01). Among ExRes, 70 (47.6%) pts experienced PD after Y3, with a median TTS-PD of 4.6 (4.1-5.1) yrs. In a landmark analysis at Y3, the 2-year TTS-PD was 68.5% (95% CI: 59.8%-75.7%) (5 yrs from treatment start), and 4-year overall survival was 86.5% (95% CI: 78.1%-91.9%) (7 yrs from treatment start). ConRes received a median of 5 (1-19) treatment regimens for MBC, with a median 1L TTS-PD of 12 (10.8-13) mo. A total of 89 (60.5%) ExRes and 214 (57.8%) ConRes underwent tumor sequencing. Data comparing genomic features between ExRes and ConRes will be presented. Conclusions In this prospective cohort, 28% of pts with HER2+ MBC had exceptional response to 1L anti-HER2 therapy. Consistent with prior data, ExRes present more frequently with de novo disease and HER2 IHC 3+ tumors. In our cohort, ExRes had a median follow-up of 7.1 years and 52.4% never experienced PD. Although a significant proportion of pts with HER2+ MBC derive long-term benefit from anti-HER2 therapy, the treatment paradigm remains palliative, and it is unknown whether biomarkers may reliably predict exceptional response and guide future treatment. Ongoing work will explore whether genomic features vary between ExRes and ConRes. Citation Format: Stefania Morganti, Tianyu Li, Katheryn Santos, Melissa Hughes, Nolan Priedigkeit, Yvonne Li, Marla Lipsyc-Sharf, Gregory Kirkner, Janet Files, Julie Kasparian, Elizabeth Grant, Gunjan Gupta, Giuseppe Curigliano, Sara Tolaney, Andrew Cherniack, Nabihah Tayob, Nancy Lin, Heather Parsons. Predictors of exceptional response to first line HER2-targeted therapy for metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-04-01.

Chemotherapy-induced complement signaling modulates immunosuppression and metastatic relapse in breast cancer

Mortality from breast cancer is almost exclusively a result of tumor metastasis and resistance to therapy and therefore understanding the underlying mechanisms is an urgent challenge. Chemotherapy, routinely used to treat breast cancer, induces extensive tissue damage, eliciting an inflammatory response that may hinder efficacy and promote metastatic relapse. Here we show that systemic treatment with doxorubicin, but not cisplatin, following resection of a triple-negative breast tumor induces the expression of complement factors in lung fibroblasts and modulates an immunosuppressive metastatic niche that supports lung metastasis. Complement signaling derived from cancer-associated fibroblasts (CAFs) mediates the recruitment of myeloid-derived suppressor cells (MDSCs) to the metastatic niche, thus promoting T cell dysfunction. Pharmacological targeting of complement signaling in combination with chemotherapy alleviates immune dysregulation and attenuates lung metastasis. Our findings suggest that combining cytotoxic treatment with blockade of complement signaling in triple-negative breast cancer patients may attenuate the adverse effects of chemotherapy, thus offering a promising approach for clinical use.

Breast cancer patients treated with intrathecal therapy for leptomeningeal metastases in a large real-life database

BackgroundLeptomeningeal metastasis (LM) is a rare complication of metastatic breast cancer (MBC), with high morbidity/mortality rates. Our study aimed to describe the largest-to-date real-life population of MBC patients treated with intrathecal (IT) therapy and to evaluate prognostic models.MethodsThe Epidemiological Strategy and Medical Economics (ESME) MBC database (NCT03275311) includes all consecutive patients who have initiated treatment for MBC since 2008. Overall survival (OS) of patients treated with IT therapy was estimated using the Kaplan–Meier method. Prognostic models were constructed using Cox proportional hazards models. Performance was evaluated using C-index and calibration plots.ResultsOf the 22 266 patients included in the database between 2008 and 2016, 312 received IT therapy and were selected for our analysis. Compared with non-IT-treated patients, IT-treated patients were younger at MBC relapse (median age: 52 years versus 61 years) and more often had lobular histology (23.4% versus 12.7%) or triple-negative subtype (24.7% versus 13.3%) (all P < 0.001). Median OS was 4.5 months [95% confidence interval (CI) 3.8-5.6] and 1-year survival rate was 25.6%. Significant prognostic factors associated with poorer outcome on multivariable analysis were triple-negative subtype (hazard ratio 1.81, 95% CI 1.32-2.47), treatment line ≥3 (hazard ratio 1.88, 95% CI 1.30-2.73), ≥3 other metastatic sites (hazard ratio 1.33, 95% CI 1.01-1.74) and IT cytarabine or thiotepa versus methotrexate (hazard ratio 1.68, 95% CI 1.28-2.22), while concomitant systemic therapy was associated with better OS (hazard ratio 0.47, 95% CI 0.35-0.62) (all P < 0.001). We validated two previously published prognostic scores, the Curie score and the Breast-graded prognostic assessment, both with C-index of 0.57.ConclusionsMBC patients with LM treated with IT therapy have a poor prognosis. We could identify a subgroup of patients with better prognosis, when concomitant systemic therapy and IT methotrexate were used.

Monitoring of therapeutic efficacy to CDK4/6 inhibitors and early detection of metastatic relapse in breast cancer by ultra-deep sequencing of plasma cell-free DNA.

e15544 Background: CDK4/6 inhibition substantially improves progression-free survival for women with advanced estrogen receptor-positive breast cancer. Despite this, most patients experience acquired resistance. The analyses of cancer specific genomic aberrations in plasma cell free DNA, or commonly referred to as ‘liquid biopsy’, has generated immense interest. The role of liquid biopsy enables monitoring of therapeutic efficacy to detect relapse in a minimally invasive manner. It would drastically impact risk stratification, treatment selection and patient clinical outcome in advanced stage breast cancer. Methods: We have recruited consecutive patients with metastatic breast cancer who received CDK4/6 inhibitor treatment in combination with endocrine therapy between April 2018 and December 2019. Somatic mutations identified by the Oncomine Pan-Cancer cell free assay were used to assess the mutation profiles of circulating tumor DNA (ctDNA) by ultra-deep sequencing (~56,000 depth) of the plasma DNA. Plasma samples (N = 146) were collected before and during treatment (2 years) or until disease progression. Paired white blood cells (WBC) were also sequenced to exclude clonal hematopoiesis-derived mutations. Results: Twenty-eight patients were enrolled. Based on RECIST criteria, 1 patient showed complete response (CR) within 18 months of treatment, 5 patients showed partial response (PR) 6-18 months from start of treatment, 9 patients showed stable disease (SD) condition within 3-18 months and 13 patients developed progressive disease (PD) within 1-12 months. In 22 of 28 patients (79%), ctDNA was detected prior to start of treatment (12 responders; 10 PD) and used as a monitoring marker. Majority of mutations detected in pre-treatment samples were TP53, PIK3CA and ESR1. Among the 12 ctDNA positive responders, ctDNA levels of 9 patients were undetectable within 2 weeks to 6 months from start of treatment (median 3 months). ctDNA profiles were more reflective of clinical response compared to the tumor markers CEA and CA15-3. In 7 of the 10 PD patients with ctDNA monitoring markers, ctDNA showed higher sensitivity to predict disease progression compared to tumor markers that remained stagnant or below normal threshold. ctDNA also predicted PD earlier than radiological images with a median lead time of 3 months. Conclusions: ctDNA assessment for therapy monitoring and early relapse detection in advanced breast cancer is feasible and provides a basis to evaluate early therapeutic interventions.

The systemic response to surgery triggers the outgrowth of distant immune-controlled tumors in mouse models of dormancy.

Patients undergoing surgical resection of primary breast tumors confront a risk for metastatic recurrence that peaks sharply 12 to 18 months after surgery. The cause of early metastatic relapse in breast cancer has long been debated, with many ascribing these relapses to the natural progression of the disease. Others have proposed that some aspect of surgical tumor resection triggers the outgrowth of otherwise-dormant metastases, leading to the synchronous pattern of relapse. Clinical data cannot distinguish between these hypotheses, and previous experimental approaches have not provided clear answers. Such uncertainty hinders the development and application of therapeutic approaches that could potentially reduce early metastatic relapse. We describe an experimental model system that definitively links surgery and the subsequent wound-healing response to the outgrowth of tumor cells at distant anatomical sites. Specifically, we find that the systemic inflammatory response induced after surgery promotes the emergence of tumors whose growth was otherwise restricted by a tumor-specific T cell response. Furthermore, we demonstrate that perioperative anti-inflammatory treatment markedly reduces tumor outgrowth in this model, suggesting that similar approaches might substantially reduce early metastatic recurrence in breast cancer patients.

Occurrence Delays of Metastatic Relapses of Breast Cancers Treated at University Hospital of Treichville (Abidjan-Cote d’Ivoire)

Objective: Describe the occurrence delays of metastatic relapses of breast cancer based on the characteristics of the original tumor. Methodology: This is a retrospective and cohort study conducted from January 2000 to December 2015 on patients with metastatic relapse of breast cancer. Results: Out of 178 patients collected, the metastatic relapses were estimated at 49%, occurring in patients with an average age of 53.4 years. The majority of the patients was educated (91.6%) and did not have a high socioeconomic level (88.2%). The initial tumors were mainly at a clinical stage III (47.8%), SBR grade III (47.2%), high index Ki 67 (46.5%), negative RH (79.3%) and HER2 negative (58%). Metastases were unique in general (62.9%), dominated by bone locations (36.6%), with an average age of occurrence of 2.4 years. After the occurrence of these metastases, the cumulative survival rate was 5% at 3 years, and zero to 5 years. Conclusion: Metastatic relapses were common with poor prognosis.

Epidemiological Aspects of Metastatic Relapse of Breast Cancer in an African Context

Objectives: This study aimed to describe the epidemiological characteristics of metastatic relapse in breast cancer at the University and Hospital Center of Treichville. Methodology: This is a cohort and retrospective study conducted from January 2000 to December 2015 on 178 patients with metastaticrelapse in breast cancer. Results: The prevalence of metastatic relapses was 49% and the patients had an average age of 53.4 years and among them, 91.6% received school education and 88.2% did not have a high socioeconomic level. The majority of initial tumors were in Stage III (47.8%), SBR III (47.2%), High Ki 67 (46.5%), Negative RH (79.3%), and HER2 negative (58%). Metastases were generally unique (62.9%), dominated by bone sites (36.6%), with an average occurrencedelay of 2.4 years. After the occurrence of metastases, the cumulative survival rate was 5% at 3 years, and nil at 5 years. Conclusion: Metastatic relapses were common with poor prognosis.

A quantitative insight into metastatic relapse of breast cancer

BackgroundMetastatic relapse is the principal source of breast cancer mortality. This work seeks to uncover unobservable, yet clinically important, aspects of post-surgery metastatic relapse of breast cancer and to quantify effects of surgery on metastatic progression. MethodsWe classified metastases into three categories: (1) solitary cancer cells that were formed before or during surgery and either circulate in blood or are lodged at various secondary sites; (2) dormant or slowly growing avascular metastases; and (3) vascular secondary tumors. We developed a general mathematical model aimed at describing post-surgery dynamics of these three metastatic states. One parametric version of the model assumed that sojourn times of metastases in the three states are exponentially distributed while another was based on Erlang distribution. Model parameters were estimated from a sample of metastatic relapse or censoring times for 673 breast cancer patients treated with surgery. ResultsWe estimated the expected number of metastases at surgery and mean sojourn times for the three states and found that both are decreasing with state number. We also computed the probability that metastatic relapse resulted from a metastasis in a given state at surgery. The values of these attribution probabilities suggest that under the Erlang model all three states have a considerable effect on metastatic relapse while in the case of exponential model this is true for states 1 and 2 only. Conclusions(1) In some patients metastasis occurred before surgery; (2) our results confirm significance of metastatic dormancy; (3) according to the model surgery stimulates escape from dormancy, promotes angiogenesis and accelerates metastatic growth in a fraction of breast cancer patients. Taken summarily, these findings call into question the benefits of primary tumor resection for certain categories of breast cancer patients.

Phase II study of vinorelbine and capecitabine as first-line treatment for metastatic breast cancer.

e12004 Background: Vinorelbine (V) and capecitabine (C) are likely to have a synergisitic interaction. Vinorelbine upregulates thymidine phosphorylase; a key enzyme in the conversion of capecitabine to active 5-FU in tumor tissue. Available phase II clinical data reports response rates ranging from 48-70% in first line metastatic breast cancer (MBC) for this combination. We evaluated the efficacy and safety of vinorelbine plus capecitabine in patients with MBC relapsing after adjuvant anthracycline based treatment. Methods: Sixty patients were enrolled between Oct 2008 through Dec 2010. All patients had measurable MBC relapse after adjuvant anthracycline and/or taxanes, WHO PS &lt; 2, adequate bone marrow, renal and hepatic functions. Patients received intravenous vinorelbine 25 mg/m2 on day 1 and 8 and oral capecitabine 1000 mg/m2 bid on days 1 to 14, cycles to be repeated every 3 weeks. Patients with PD went off the study while those with CR, PR or SD continued treatment for a maximum of 8 cycles. Results: Median age 54 years (range 35-67 years), Median WHO PS 0 (range 0-1). Previous adjuvant therapy anthracycline (100%) and hormone therapy (60%). Median disease free interval was 6 months. Main metastatic sites were lung (40%), liver (25%), bone (40%) skin (35%), and lymph nodes (35%). Twenty five percent of patients had one metastatic site, 60% had two sites, 10% had three sites and 5% had more than three sites. The total number of cycles delivered was 441 with a median number of cycles/patients of 7 (range 3-8). An objective tumor response was achieved in 36 pts (60%), complete response (CR) in 6 pts (10%), 12 pts (20%) had stable disease (SD). After a follow up period of 6-36 months, the median time to progression and median survival were 14 and 23 months, respectively. No WHO G4 toxicities were noted, 3 pts (5%) developed G3 neutropenia and one patient (1.7%) developed G3 hand and foot syndrome. G2 anemia, neutropenia and diarrhea were reported in 2 pts (3.3%), 3 pts (5%) and 6 pts (10%), respectively. Conclusions: The combination of vinorelbine and capecitabine showed significant efficacy and mild toxicity as a first-line treatment for patients with metastatic breast cancer after failure of adjuvant anthracycline based therapy.

When to order a biopsy to characterise a metastatic relapse in breast cancer

Today, the diagnosis of metastatic breast cancer is usually based on radiological findings, and therapeutic decisions are made by considering the pathological characteristics and predictive markers of the primary tumour. Accumulating evidence suggests that tumour characteristics, including estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2), are unstable through tumour progression. Several retrospective studies and, recently, two prospective studies have investigated the discrepancies in receptor status between primary tumours and the corresponding metastases in a total of 1773 patients (for ER) and 2845 patients (for HER2). Changes in ER and HER2 status in these studies range from 14.5% to 40% and from 0% to 37.5%, respectively. In the two prospective studies, a different diagnosis, usually non-malignant, was obtained in 3% and 9% of the cases, and the biopsy led to a treatment modification in about one out of seven patients. Here, we review and discuss the currently available data and provide our recommendations on when a metastatic biopsy should be obtained.

339P - Fulvestrant 500 Mg as First-Line Treatment in Hormone-Positive (HR+) Metastatic Breast Cancer (MBC) Patients (PTS): Prospective Evaluation of Activity, Safety, Quality of Life (QOL) and Tumour Markers Changes

ABSTRACT Background Fulvestrant 500 mg has been shown to have a biologically greater effect and to produce a clinical meaningful benefit over Fulvestrant 250 mg. We carried out a prospective phase II trial to evaluate the activity and safety of such an option as 1st line treatment of HR+ MBC; an analysis of QoL, patient compliance, and prognostic value of tumour markers monitoring was also performed. Patients and methods Pts with HR+ MBC relapsing after Tamoxifen and/or Aromatase Inhibitors adjuvant therapy received Fulvestrant 500 mg i.m. on day 0, then 500 mg on days 14-28 and every 28 days thereafter, until disease progression or unacceptable toxicity or patient refusal. Changes in cancer antigen 15.3 (CA 15.3) and carcinoembryonic antigen (CEA) were monitored monthly over treatment; QoL and treatment tolerability were assessed every 2 cycles. Results Forty-eight consecutive pts were enrolled and treated. The overall clinical benefit rate was 68%, with 3 (6%) complete (CR) and 12 (25%) partial responses (PR), and 18 (48%) stable diseases (SD ) lasting >24 weeks. The median PFS was 11 months, median response duration was 9 months. Toxicity was manageable, also in pts given long-duration therapy (>18 months). Analysis of QoL by QLQ-BR23 showed no deterioration of the evaluated items over treatment, while the compliance assessment documented an improvement of tolerability of treatment compared with their previous adjuvant hormonotherapy. In pts achieving a CR or PR both CA 15.3 and CEA serial levels decreased significantly over the first 4 months of treatment, while in long-lasting SD a statistically significant difference from baseline was reached within a median of 8 months. Conclusions Our results confirm the known activity and tolerability of Fulvestrant 500 mg as 1st line therapy for HR+ MBC, with good patient compliance over long-term treatment and preservation of QoL. Of interest, changes in tumour markers resulted significantly predictive of treatment activity in responding pts, in contrast with previously reported data with Fulvestrant 250 mg, reflecting and additional difference between the two drug dosages. Disclosure All authors have declared no conflicts of interest.

Testing for Discordance at Metastatic Relapse: Does It Matter?

In the articles that accompany this editorial, two studies are reported that challenge the belief that a biopsy at the time of metastatic breast cancer relapse is not routinely required, because it provides no further information in regard to the optimal treatment of an individual patient’s tumor. Amir et al 1 report on a prospective trial assessing the clinical impact of tissue confirmation of metastatic disease in patients with breast cancer, and Niikura et al 2 describe rates of discordance and survival in a large single-institution cohort of patients with human epidermal growth factor 2 (HER2) positive primary breast cancer who had a metastatic tumor biopsy result available. Both of these studies are important for solidifying the results of numerous retrospective studies that have consistently demonstrated a discordant rate for either the estrogen receptor (ER) or HER2 receptor between the primary tumor and metastatic lesion. Although it is rational to attempt a biopsy for confirmation of metastatic disease for prognostic purposes, perhaps more contentious are the potential reasons behind, and the resultant clinical consequences of, an apparent discordant result. In the pragmatic and well-designed prospective cohort study by Amir et al, 1 patients presenting with evidence suggestive of metastatic disease or who were experiencing progression while receiving a palliative systemic treatment were enrolled. Strengths of the study were that the primary end point of the study was the proportion of patients in whom the biopsy result led to a change in systemic management, with secondary end points including patient-reported outcomes related to patient satisfaction. Neither of these important end points can be properly measured by means of retrospective study. The main conclusion of the study was the finding of discordance in either ER or HER2 in 16% and 10% of patients, respectively. In 14% of all patients enrolled, the biopsy result led to a reported change in management, with 88% of all participants stating they would recommend the biopsy procedure to other patients. In the retrospective study from the MD Anderson Cancer Centre (MDACC), 182 patients with HER2-positive primary breast cancers were identified, of whom 24% (n 43) were found to have an HER2-negative metastatic lesion on review. 2 Furthermore, the investigators demonstrated that the patients with a discordant HER2 result (HER2-positive primary disease but HER2-negative metastases) had worse survival than the patients with a concordant HER2 result (hazard ratio, 0.43; P .003). Strengths of this study were the relatively large cohort of HER2-positive primary breast cancers identified, the attempted central review of HER2 results (for those patients who were originally assessed at other institutions), and correlation of treatments and outcome between discordant and concordant subgroups. A discordant rate of approximately 25% in either ER or HER2 is well within the range seen in several recent larger retrospectives studies as well as one prospective study (BRITS [Breast Recurrence in Tissues Study]). 3-9 This range of discordance, between 20% and 30%, has been repeatedly demonstrated in these studies despite differences in methodology of assessment for the biomarkers between the primary and relapsed lesions, inclusion of both local and regional relapses with the distant tumors, and heterogeneity in patient populations. Despite

P5-01-07: Identification of SORBS2 as a Candidate Marker To Predict Metastatic Relapse in Breast Cancer.

Abstract Background Elucidation of promising cancer biomarkers from gene expression data can provide important insight into the relationship between signaling networks and cancer. SORBS2, sorbin and SH3 domain containing 2, is a multi-adapter protein involved in signal transduction associated to the cytoskeleton and was reported to be strongly repressed in pancreatic and cervical cancers. Methods: With the purpose of identifying genes involved in metastatic process, we compared gene expression profiling of 19 invasive ovarian cancers and 24 borderline tumors. Prognostic value of the selected genes was then tested in a gene expression array database that includes 1659 patients with early breast cancer (Gyorffy B et al. 2010). Upon isolation of SORBS2 as a predictor, its involvement in cell migration and tumor progression was investigated in vitro. Small interfering RNA targeting SORBS2 was used to downregulate its expression in T47D and Hela, two cell lines overexpressing SORBS2. Functional effect of siRNA-induced knockdown of SORBS2 on cell viability was determined by WST-1 assay and Trypan Blue exclusion test. Effect on cell migration was evaluated by wound-healing and transwell assays. Western blot analyses were also performed to examine the expressions of proteins involved in cell survival, death and migration. Results: High-throughput analyses of genes that are differentially expressed between borderline ovarian tumors and invasive carcinoma demonstrated that SORBS2 is significantly downregulated in invasive carcinoma (FDR&amp;lt;10e-10). Moreover, SORBS2 loss was a strong predictor of relapse in a gene expression array dataset of 1659 patients presenting an early breast cancer (HR=0.62, 0.52−0.72, p=6.4e-10). In vitro studies showed that SORBS2 specific downregulation stimulated cell proliferation, by an average of 40%, in T47D and Hela cell lines. SORBS2 knockdown had no effect on either cell migration rate or protein expressions of p-FAK and p-Paxillin, two focal adhesion proteins which are critical to cell adhesion and migration. No significant variations in protein expressions of Akt/mTOR pro-survival or caspases activation pathways were observed. Gene expression profiling before and after SORBS2 dowregulation is ongoing in the two cell lines. Conclusion: This study is the first to provide evidence for an antiproliferative activity of SORBS2 with no effect on cell migration in breast cancer cells. Our clinical and in vitro data suggest that SORBS2 is a candidate marker to predict relapse in patients with early breast cancer. Molecular mechanisms mediating the antiproliferative effect of SORBS2 are currently being investigated. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-07.

Abstract 3099: Role of the transcription factor iroquois homeobox 2 (IRX2)in breast cancer progression and metastasis

Abstract The onset of the metastatic cascade -the main cause of cancer-related death- is the dissemination of single tumor cells into distant organs. The presence of disseminated tumor cells (DTC) in the bone marrow (BM) of cancer patients is an independent prognostic factor for the occurrence of metastatic relapse in breast cancer and other epithelial tumors. Our current results suggest that the transcription factor IRX2 might represent a novel tumor suppressor gene which might in particular contribute to early hematogenous dissemination. The purpose of this study is to gain insights into the role of the transcription factor IRX2 during breast cancer progression and metastasis. In order to identify genes that could account for early hematogenous dissemination we compared expression profiles of primary breast tumors with or without detectable DTC in the BM. We further analyzed the transcript expression by quantitative RT-PCR analysis in an independent set of primary breast tumor samples. With the purpose to provide further evidence about the clinical relevance and the biological function of the IRX2 transcription factor we also performed different computer-based analyses using a large publicly available patient data set. Potential transcriptional targets of the IRX2 protein were moreover validated in IRX2-knock-down model systems and by gene-reporter-assays. We were able to discover that low IRX2 expression in primary breast tumors is associated with BM status. In addition, we could show that low IRX2 expression was associated with decreased long time survival of breast cancer patients. Furthermore, by using stringent thresholds in a bioinformatical approach we could identify 22 potential transcriptional targets of the IRX2 transcription factor. Most interestingly, we found that LRIG1 might be a crucial target of the IRX2 gene product. We could reveal a positive correlation between IRX2 and LRIG1 expression in primary breast tumors and we could identify a IRX2 binding site in the proximal LRIG1-promotor which is effectively transactivated by the IRX2 protein in vitro. Additionally we could show that shRNA-mediated knock-down of IRX2 expression in cultured breast cancer cell lines is attended by decreased LRIG1 expression. Our present results imply that the IRX2 gene product might represent a novel tumor suppressor protein. Loss of IRX2 expression could contribute in particular to early hematogenous dissemination. In addition, our findings show a direct transcriptional regulation of LRIG1 by the IRX2 transcription factor. Since LRIG1 is an important negative regulator of receptor tyrosine kinases, we assume that decreased IRX2 expression may led to a more aggressive phenotype by sustaining the over expression of receptor tyrosine kinases, like EGFR and ERBB2. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3099. doi:10.1158/1538-7445.AM2011-3099

Chemokine (C-C Motif) Ligand 2 Engages CCR2+ Stromal Cells of Monocytic Origin to Promote Breast Cancer Metastasis to Lung and Bone

Metastatic spread of cancer to distant vital organs, including lung and bone, is the overwhelming cause of breast cancer mortality and morbidity. Effective treatment of systemic metastasis relies on the identification and functional characterization of metastasis mediators to multiple organs. Overexpression of the chemokine (C-C motif) ligand 2 (CCL2) is frequently associated with advanced tumor stage and metastatic relapse in breast cancer. However, the functional mechanism of CCL2 in promoting organ-specific metastasis of breast cancer has not been rigorously investigated. Here, we used organ-specific metastatic sublines of the MDA-MB-231 human breast cancer cell line to demonstrate that overexpression of CCL2 promotes breast cancer metastasis to both lung and bone. Conversely, blocking CCL2 function with a neutralizing antibody reduced lung and bone metastases. The enhancement of lung and bone metastases by CCL2 was associated with increased macrophage infiltration and osteoclast differentiation, respectively. By performing functional assays with primary cells isolated from the wild type, CCL2 and CCR2 knock-out mice, we showed that tumor cell-derived CCL2 depends on its receptor CCR2 (chemokine, CC motif, receptor 2) expressed on stromal cells to exert its function in promoting macrophage recruitment and osteoclast differentiation. Overall, these data demonstrated that CCL2-expressing breast tumor cells engage CCR2(+) stromal cells of monocytic origin, including macrophages and preosteoclasts, to facilitate colonization in lung and bone. Therefore, CCL2 and CCR2 are promising therapeutic targets for simultaneously inhibiting lung and bone metastasis of breast cancer.

Prévalence de l'élévation du CA 15-3 lors de la rechute métastatique des cancers du sein: corrélation avec l'expression des récepteurs hormonaux et de Her2

CA15-3, a peptide derived from MUC-1, an hormonally-regulated protein, is the most widely used serum marker of breast cancer. CA15-3 level increases at the metastatic phase in 50-80% breast cancer patients. Although rise of CA15-3 precede symptoms of metastasis by a mean time of 2-9 months, current international guidelines do not recommend its routine use for screening for metastases because of moderate sensitivity and absence of clinical impact. We conducted a retrospective study among all patients with metastatic breast cancer seen by three senior breast oncologists during a 4-month period. We evaluated correlation of CA15-3 level at the time of metastatic relapse with ER, PgR and Her2 expressions, tumor type, size and nodal status at initial diagnosis, and sites of metastases. CA15-3 was increased in 168/272 patients (62%) at diagnosis of metastases. ER/PgR positivity was strongly correlated with elevated CA15-3 at this time (P < 0.0001). CA 15-3 was elevated in 69% of the cases of HR+ Her2- primary tumors at time of metastatic relapse. It was elevated in 56% of HR+ Her2+++, 46% of HR- Her2+++ cases and only in 41% of triple-negative cases (P = 0.003). these data confirm that CA 15-3 is very variably elevated at time of metastatic relapse of breast cancer, and this is dependant on HR status.

Learning to predict relapse in invasive ductal carcinomas based on the subcellular localization of junctional proteins

The complexity of breast cancer biology makes it challenging to analyze large datasets of clinicopathologic and molecular attributes, toward identifying the key prognostic features and producing systems capable of predicting which patients are likely to relapse. We applied machine-learning techniques to analyze a set of well-characterized primary breast cancers, which specified the abundance and localization of various junctional proteins. We hypothesized that disruption of junctional complexes would lead to the cytoplasmic/nuclear redistribution of the protein components and their potential interactions with growth-regulating molecules, which would promote relapse, and that machine-learning techniques could use the subcellular locations of these proteins, together with standard clinicopathological data, to produce an efficient prognostic classifier. We used immunohistochemistry to assess the expression and subcellular distribution of six junctional proteins, in addition to a panel of eight standard clinical features and concentrations of four "growth-regulating" proteins, to produce a database involving 36 features, over 66 primary invasive ductal breast carcinomas. A machine-learning system was applied to this clinicopathologic dataset to produce a decision-tree classifier that could predict whether a novel breast cancer patient would relapse. We show that this decision-tree classifier, which incorporates a combination of only four features (nuclear alpha- and beta-catenin levels, the total level of PTEN and the number of involved axillary lymph nodes), is able to correctly classify patient outcomes essentially 80% of the time. Further, this classifier is significantly better than classifiers based on any subgroup of these 36 features. This study demonstrates that autonomous machine-learning techniques are able to generate simple and efficient decision-tree prognostic classifiers from a wide variety of clinical, pathologic and biomarker data, and unlike other analytic methods, suggest testable biologic relationships among explicitly identified key variables. The decision-tree classifier resulting from these analytic methods is sufficiently simple and should be widely applicable to a spectrum of clinical cancer settings. Further, the subcellular distribution of junctional proteins, which influences growth regulatory pathways involved in locoregional and metastatic relapse of breast cancer, helped to identify which patients would relapse while their total concentration did not. This emphasizes the need to evaluate the subcellular distribution of junctional proteins in assessing their contribution to tumor progression.

Prognostic value of serum level of HER-2 extracellular domain (ECD) at diagnosis of HER-2 overexpressed primary breast cancer (BC)

e11508 Background: Serum level of HER2 ECD is an adverse prognostic factor in HER2 over-expressed metastatic BC. We analyzed the prognostic value of serum level of HER2 ECD at the diagnostic of HER2 over-expressed primary BC. Methods: Patients with HER2 over-expressed primary BC treated with adjuvant trastuzumab in 2005 and 2006 were retrospectively analyzed. Serum level of HER2 ECD was assessed on frozen sera collected for CA15–3 measurement before initial treatment. Serum level of HER2 ECD was measured with an Elisa commercial kit (Oncogene Science, Cambridge, MA). The cut-off was 15μg/l as recommended. Results: Pre-treatment serum was available for 65 patients treated for non metastatic HER2 over-expressed BC. Seven patients (11%) had initially an elevated serum level of HER2 ECD (mean 25μg/l, range 15.1–38.9). After an average follow-up of 30 months, 4 patients (57%) out of the 7 with initially elevated serum level of HER2 ECD had a metastatic relapse of BC. In contrast, only 3 patients (5%) out of 58 with initially low serum level of HER2 ECD experienced relapse (p=0.004). Median of serum level of HER2 ECD was 17μg/l in patients who experienced relapse during follow-up whereas it was 8.4μg/l in patients who remained relapse-free (p=0.03). Univariate analysis showed that only elevated serum level of HER2 ECD and absence of hormone receptors expression were linked with metastatic relapse (p=0.0004 and p=0.02, respectively). Multivariate analysis showed that elevated serum level of HER2 ECD and absence of hormone receptors expression were linked with metastatic relapse (p=0.02 and p=0.04, respectively). Survival curves showed also that elevated serum level of HER2 ECD was related with a worse disease-free survival (p=0.0004). Conclusions: In this small series, elevated serum level of HER2 ECD was an adverse prognostic factor for HER2 over- expressed non metastatic primary BC. It was also a predictive factor for early failure of adjuvant treatment with trastuzumab. No significant financial relationships to disclose.

Risk factors for brain metastases in patients with a metastatic relapse of breast cancer

837 Background: Brain metastases are a more and more frequent, difficult clinical problem in advanced breast cancer (BC) patients (pts). We searched for risk factors of brain metastasis (BM) among pts diagnosed with a metastatic relapse of BC. Methods: A total of 557 premenopausal BC pts receiving systematic adjuvant chemotherapy were accrued at Institut Gustave-Roussy in a randomized trial of ovarian suppression [Arriagada et al, ASCO 03]. After a median follow-up of 9.5 years, 215 developed a first metastasis at a site other than brain alone. Of these 215 metastatic patients, 31 developed BM. The risk of BM in these 215 patients was analyzed as a function of patient, tumor and treatment characteristics by Cox models. Risk factors identified in the multivariate analysis were re-evaluated in a confirmatory series of 199 patients with metastatic relapse registered at Institut Gustave-Roussy in two randomized adjuvant chemotherapy trials (691 postmenopausal node-positive pts [Arriagada et al, Ann Oncol 2002] and 247 premenopausal node-negative pts [Arriagada et al, submitted]). Of these 199 pts, 19 developed BM. Results: In the first series, risk factors for BM in univariate analyses were lung metastasis as first site (yes/no): 2-year incidence rates of BM 24% vs 7% (p<0.001), negative hormone receptor (HR- vs HR+): 2-year BM rates 34% vs 5% (p<0.001) and short interval between BC and metastatic relapse (≤ vs >24 months): 18% vs 6% (p<0.008). In the multivariate analysis, only lung metastases remained prognostic (RR 5.3, 95% confidence interval (95%CI): 2.6–11, p<0.001). This was confirmed in the second series where the 2-year rates of BM were respectively 44% [95% CI: 26%–64%] and 3% [95%CI: 1–7%] in pts with or without lung metastases (RR 10 [95%CI: 3.8–27], p< 0.0001). Conclusions: This study shows that lung metastasis is a strong risk factor for the occurrence of brain metastases among BC patients. The occurrence of brain and lung metastases could be due to a common, albeit unknown, biological determinant. We suggest that prophylaxis of brain metastases may be evaluated in BC patients with lung metastases. No significant financial relationships to disclose.

Risk factors for brain metastases in patients with a metastatic relapse of breast cancer

837 Background: Brain metastases are a more and more frequent, difficult clinical problem in advanced breast cancer (BC) patients (pts). We searched for risk factors of brain metastasis (BM) among pts diagnosed with a metastatic relapse of BC. Methods: A total of 557 premenopausal BC pts receiving systematic adjuvant chemotherapy were accrued at Institut Gustave-Roussy in a randomized trial of ovarian suppression [Arriagada et al, ASCO 03]. After a median follow-up of 9.5 years, 215 developed a first metastasis at a site other than brain alone. Of these 215 metastatic patients, 31 developed BM. The risk of BM in these 215 patients was analyzed as a function of patient, tumor and treatment characteristics by Cox models. Risk factors identified in the multivariate analysis were re-evaluated in a confirmatory series of 199 patients with metastatic relapse registered at Institut Gustave-Roussy in two randomized adjuvant chemotherapy trials (691 postmenopausal node-positive pts [Arriagada et al, Ann Oncol 2002] and 247 premenopausal node-negative pts [Arriagada et al, submitted]). Of these 199 pts, 19 developed BM. Results: In the first series, risk factors for BM in univariate analyses were lung metastasis as first site (yes/no): 2-year incidence rates of BM 24% vs 7% (p<0.001), negative hormone receptor (HR- vs HR+): 2-year BM rates 34% vs 5% (p<0.001) and short interval between BC and metastatic relapse (≤ vs >24 months): 18% vs 6% (p<0.008). In the multivariate analysis, only lung metastases remained prognostic (RR 5.3, 95% confidence interval (95%CI): 2.6–11, p<0.001). This was confirmed in the second series where the 2-year rates of BM were respectively 44% [95% CI: 26%–64%] and 3% [95%CI: 1–7%] in pts with or without lung metastases (RR 10 [95%CI: 3.8–27], p< 0.0001). Conclusions: This study shows that lung metastasis is a strong risk factor for the occurrence of brain metastases among BC patients. The occurrence of brain and lung metastases could be due to a common, albeit unknown, biological determinant. We suggest that prophylaxis of brain metastases may be evaluated in BC patients with lung metastases. No significant financial relationships to disclose.