P2-01-13: Impact of Erlotinib on MSC-Mediated TIC Expansion and EMT

Background: Recently, we have demonstrated that mesenchymal stem cells (MSC) and MSC secreted factors (MSC-CM) have a profound effect on tumor initiating cells (TIC) enriched mammosphere formation and latency of tumor xenografts formation from breast cancer cell lines. Furthermore these interactions increased the expression of epithelial mesenchymal transition (EMT)-associated proteins which are associated with tumor cell invasion and metastasis as well as the TIC phenotype. (Klopp, A. H. et al., 2010, PLoS One. 5, e12180). Our data suggest that the presence of MSC in the tumor microenvironment may increase metastases by conferring stem progenitor cell biology on more differentiated non-metastatic cells. In addition, preliminary data suggested MSC-CM upregulated EGFR signaling in breast cancer cells. Therefore, we hypothesized that inhibiting EGFR signaling with erlotinib (tyrosin kinase inhibitor) can suppress MSC-mediated TIC expansion and EMT.

Methods & Results: In order to demonstrate that erlotinib inhibits MSC-CM promoted expansion of TIC, we cultured breast cancer cells lines (SUM149, SUM159, SUM190, MDA-IBC3 and MCF-7) in anchorage independent conditions with MSC-CM and treated them with increasing concentrations of erlotinib. The efficiency of mammosphere formation was examined after 5 days. We found that erlotinib inhibited MSC mediated increase in mammosphere formation in triple negative cell lines SUM149 and SUM159, and HER2−positive cell lines SUM190 and MDA-IBC3, but not in ER-positive, erlotinib resistant MCF-7 cells. Furthermore, we evaluated the impact of erlotinib on cell cultures grown with breast cancer patient-derived fluids, such as seroma and malignant pleural effusions. We observed that the effect of erlotinib on mammospheres formation was attenuated by both types of patient fluids.

Discussion: Patients with triple negative breast cancer have the highest rates of metastases and no available targeted therapies for treatment. EGFR is expressed in a significant proportion of triple negative breast cancers, and recent clinical and preclinical studies suggest that EGFR may contribute to the metastasis or aggressiveness of triple negative breast cancer. Here we demonstrate that host and environmentally-derived factors are critical for determining resistance to erlotinib. In vivo studies regarding the ability of erlotininb to prevent MSC-enhanced TIC survival and metastases are underway.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-01-13.

P1-04-01: The Mechanism of Anti-Breast Cancer TICs Effect of Pyrvinium Pamoate Is through WNT/beta-Catenin Signaling

We have previously shown that pyrvinium pamoate can decrease breast cancer TICs in vitro and shrink the tumor size in vivo. Although pyrvinium pamoate has been shown to target beta-catenin through activating CK-1alpha in a vitro model, the mechanism of its anti-breast cancer TICs effect is unknown. Herein, we use a constitutively active WNT/beta-catenin signaling construct EBETAP (ref) to determine if the anti-breast TIC effect of pyrvinium pamoate is through WNT/beta-catenin signaling. Using aldefluor expression and mammosphere formation efficiency as TIC surrogate assays, we found that TICs of SUM-159 transfected with EBETAP construct are resistant to pyrvinium pamoate treatment compared to control cells. Moreover, microarray analysis reveals a series of genes and signaling downstream of WNT-catenin were down-regulated in SUM-159 cells treated with pyrvinium pamoate. In summary, mechanism of anti-breast cancer TICs effect of pyrvinium pamoate is through WNT/beta-catenin signaling.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-01.

P5-01-17: HER2 Amplification in Primary Tumor: A Potential Marker for Presence of Circulating Tumor Cells in Inflammatory Breast Cancer Patients?

Background: Inflammatory breast cancer (IBC) is a rare but aggressive form of invasive breast cancer accounting for 3–6% of all cases and have higher rates of distant recurrence. Circulating tumor cells (CTCs) are known to predict outcome in metastatic breast cancer (BC) patients, but little is known about their prognostic significance in non-metastatic BC. We hypothesized that CTCs can be identified in patients with IBCs and may correlate with primary tumor characteristics. Methods: All patients had blood samples collected at the time of primary surgery. CTCs (per 7.5 ml blood) were detected using the Cell Search™ system (Veridex) and were defined as nucleated cells lacking CD45 but expressing cytokeratins (CK) 8, 18, or 19. The presence of ≥ 1 epithelial cells meeting morphologic criteria for malignancy was considered a positive result. Statistical analyses employed Chi square and Fisher's exact tests using STATA IC 11. Results: We prospectively evaluated 41 IBC patients enrolled in an IRB approved protocol undergoing surgery for stage I-III breast cancer. Median follow-up was 30 months. Mean age was 52 years. Thirty five patients (94%) had positive lymph nodes (LNs) at presentation, 30 (75%) had high-grade tumors and 20 (53%) had lymphovascular invasion. Eleven patients (28%) were ER positive, 11 (27%) were PR positive and 18 (44%) were HER2 positive. IBCs were more likely to be high grade (P<0.0001), ER negative (P<0.0001), PR negative (P<0.0001), HER2 positive (P<0.0001), High Ki-67 (P= 0.005) and had a BMI of more than 25kg/m2 (P=0.04). Eleven (27%) patients were CTC positive. CTCs were more likely be found in HER2 positive (8/18; 44%) vs. HER2 negative primary tumors (3/20; 15%) [OR= 4.53; 95% C.I. = 1.02−19.52; P= 0.04]. We found no statistically significant correlations between primary tumor characteristics (ER, PR, LNs, high grade) and presence of CTCs. Conclusions: About a quarter of IBC patients had CTCs at the time of primary surgery. In these patients HER2 overexpression predicted the presence of CTCs. Studies with longer follow-ups is needed to determine if CTCs predicted survival.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-17.

The diagnostic accuracy of high-resolution endoscopy, autofluorescence imaging and narrow-band imaging for differentially diagnosing colon adenoma

BACKGROUND AND STUDY AIMS

Conventional colonoscopy can result in unnecessary biopsy or endoscopic resection due to its inability to distinguish adenomas from hyperplastic polyps. This study therefore evaluated the efficacy of high-resolution endoscopy (HRE), autofluorescence imaging (AFI), and narrow-band imaging (NBI) in discriminating colon adenoma from hyperplastic polyps.

PATIENTS AND METHODS

This was a prospective multicenter study in patients undergoing AFI and NBI examinations. HRE, AFI, and NBI images were classified into two groups based on morphological characteristics, the predominant color intensities, and the visibility of meshed capillary vessels, respectively. Each of the endoscopic photographs were independently evaluated by a single endoscopist. The images were then assessed by three specialists and three residents, the latter having performed < 500 colonoscopies and < 30 NBI and AFI examinations. Diagnostic test statistics were calculated to compare the accuracy in differentiating colon adenoma from hyperplastic polyps for each method.

RESULTS

A total of 183 patients were enrolled in the study and 339 adenomas and 85 hyperplastic polyps were identified. AFI and NBI could distinguish adenoma from hyperplastic polyps with an accuracy of 84.9 % and 88.4 %, respectively, whereas HRE exhibited an accuracy of 75.9 %. In the 358 lesions in which the AFI diagnosis was consistent with that of NBI, the accuracy, sensitivity, and specificity were high, at 91.9 %, 92.7 %, and 92.9 %, respectively. During the study comparing specialists and residents, AFI and NBI dramatically improved the diagnostic accuracy of residents from 69.1 % to 86.1 % and 84.7 %, respectively.

CONCLUSIONS

Both AFI and NBI are considered to be feasible tools that can discriminate colon adenoma from hyperplastic polyps, and their use may be particularly beneficial for less-experienced endoscopists.

Abstract P6-14-06: Prospective Testing of Three Different Gene-Signatures for Patient Selection for Dasatinib Therapy in Metastatic Breast Cancer

Background: Several gene signature-based predictors of response to targeted drugs have been proposed in the literature but none has been prospectively tested as patient selection tools in the clinic. The goal of this trial is to assess the positive predictive value of 3 conceptually different multi-gene signatures as predictors of response to the multitargeted kinase inhibitor dasatinib.

Methods: This clinical trial requires biopsy of a metastatic lesion for gene expression profiling and employs a parallel, multi-arm, two-step, phase II design. Three markers are assessed including a (i) cell-line derived dasatinib-sensitivity signature, (ii) a src-pathway activity signature and (iii) a dasatinib target index calculated as the weighted average expression of all known dasatinib targets. Only markerpositive patients are treated with dasatinib 100 mg po daily and each marker arm is considered as a separate study with early stopping rules for futility (minimum sample size 9, maximum sample size 40/marker arm). A predictor is considered worthy of further study if the clinical benefit rate (i.e. positive predictive value) is ≥25%.

Results: Forty seven patients were accrued from July 2009 through June, 2010, 49 biopsies were performed (soft tissues n=31, liver n=8, bone n=3, lung n=1, adrenal gland n=1), 6 samples had poor cellularity and 3 failed array QC. There was no patient recall, hospitalization or emergency room visit due to biopsy procedure. The median time from biopsy to genomic prediction result was 5 days (range 3-7). Twenty three (57%) patients had positive result for at least 1 predictor (5 were positive for 2) and 20 are receiving therapy (3 withdraw or progressed before therapy began). Responses as of June 2010; Target index arm (n=9): 5 PD (progressive disease), 4 SD (3 stable disease at 8 weeks 1 SD at 16 weeks); SRC Pathway arm (n=5): 3 PD, 2 SD at 8 weeks; Cell line predictor arm (n=6): 2 PD, 1 SD at 8 weeks, 3 not yet reached response evaluation. None of the 3 predictive marker arms have met early stopping yet and accrual is ongoing. Conclusion: Gene-expression signature based patient selection for targeted therapy is feasible and FNA biopsies of metastatic lesions for genomic testing are safe. Updated efficacy results will be reported.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-14-06.

p53 Mutation in Inflammatory Breast Cancer Cell Lines

Background: Inflammatory breast cancer (IBC) is the most aggressive manifestation of primary breast cancer and represents 1% to 2% of primary breast cancer in the United States. IBC is characterized by an acute inflammation of the skin of the affected breast generally believed to be caused by blockage of the dermal lymphatics by tumor emboli. Wild type (WT) p53 is a tumor suppressor gene, which induces apoptosis and p53 mutations are associated with poor prognosis in breast cancer. Compared with locally advanced breast cancers, IBC patients have higher levels of mutated p53 protein that has been associated with more aggressive tumors, anthracycline resistance, shorter progression free survival, shorter overall survival, and less favorable long-term outcome. The aim of this study was to determine if there are unique genetic variations in IBC cell lines that would provide specific genetic p53 mutations that could be exploited for targeted therapy with the intent of improving response to treatment and overall survival in IBC.Materials and Methods: Genomic DNA was extracted from six breast cancer cell lines (MDA-453, SUM149, MCF-7, KPL4, MDA321, and SUM190) and the immortalized human mammary epithelial cells (HMLE) using the Qiagen DNA Blood Mini Kit (Valencia, CA). Among the 6 breast cancer cell lines, KPL-4, SUM149 and SUM190 are IBC cell lines; MDA231 and SUM149 have basal-like phenotype; MCF-7 has wild-type p53; SUM190 and KPL-4 are Her2 amplified. The DNA purity and concentration were determined by spectrophotometric measurements of absorbance at 260nm and 280 nm. Polymerase chainreaction (PCR) was performed to amplify the fragments of exons 2-11 of the p53gene using consensus primers. The PCR products were scanned and identified using the Agilent Bioanalyzer 2100. DNA sequencing was performed on PCR products in the ABI PRISM 310 Genetic Analyzer. The BLAST search was used to identify p53 mutations compared with the reference sequence, X54156, from Genbank.Results: We screened 2-11 exon sequences of the p53 gene in the 7 human breast cell lines. We identified two IBC cell lines (SUM149, SUM-190) with a p53 gene alteration that predicted a change in the encoded protein, SUM149 at exon 7 (ATG to ATA, Met-237-Ile) and SUM190 at exon 9 (CAG to TAG, Gln -317-stop). Both mutations have been previously reported. Five nonsense mutations were identified in two other cell lines, MDA-453 and MDA321. No mutations were identified in KPL4 and HMLE cells.Conclusions: The p53 mutation profile in breast cancer cell lines suggests an additional biological feature for the characterization of IBC. Furthermore, these data support the previously reported association between p53 status and chemo- and radioresistance in this disease responsible for poor prognosis. Therapies directed to restore p53 function should be explored in IBC models and in clinical trials.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3161.

Circulating Tumor Cells and FDG-PET/CT for the Therapeutic Monitoring of Bone Metastases from Breast Cancer

Background: Circulating tumor cells (CTCs) and [18F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) are two promising new tools for monitoring therapy in patients with metastatic breast cancer. The two modalities showed high sensitivity in detection of bone relapse/progression from breast cancer (De Giorgi U et al. Ann Oncol 2009). In this study, we sought to evaluate the prognostic significance of two different modalities represented by the detection of CTC and FDG-PET/CT in patients with bone metastases from breast cancer treated with standard therapies. Our objective was to compare the two modalities to identify which technology could be more sensitive in prospectively monitoring such patients.Patients and Methods: This is a retrospective study of 54 patients with bone metastases from breast cancer without visceral metastases treated at The University of Texas M. D. Anderson Cancer Center from September 2004 to May 2008. CTC were detected and enumerated using the CellSearch system (Veridex LLC, Rariten NJ, USA). Patients were categorized according to first follow-up CTC counts as having a favorable (&lt; 5 CTC/7.5 mL of blood) or unfavorable (≥ 5 CTC) outcome. Reassessment of disease status by CTC count and FDG-PET/CT was performed approximately 2-3 months after initiation of the new treatment, depending on treatment type and schedule. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier product limit method, and compared between groups with the log-rank test.Results: In 54 evaluable patients, the median overall survival time was 17 months (range, 3 to &gt;36). Follow-up CTC levels and FDG-PET/CT response predicted both PFS (p = 0.02 and p = 0.0001, respectively) and OS (p = 0.01 and p = 0.02, respectively), while baseline CTC predicted neither PFS (p = 0.8) nor OS (p = 0.76). In patients with either CTC or FDG-PET/CT response PFS has been 13 months, while in patients with discordant CTC and FDG-PET/CT response PFS has been 6 months and in patients with neither CTC nor FDG-PET/CT response PFS has been 5 months (p = &lt;0.00002). In patients with either CTC or FDG-PET/CT response, OS has not been reached (&gt;31 months); in patients with discordant CTC and FDG-PET/CT response, OS has been 24 months; and in patients with neither CTC nor FDG-PET/CT response, OS has been 18 months (p = 0.02).Conclusions: CTC and FDG-PET/CT are useful tools for therapeutic monitoring of bone metastases from breast cancer. Prospective studies in this specific clinical context are needed to assess the critical roles that CTC and FDG-PET/CT individually as well as collectively play in the prognostic and therapeutic monitoring of bone metastases from breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1109.

Addition of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) to Trastuzumab Stabilizes Disease in Patients with Trastuzumab-Resistant, HER2+ Metastatic Breast Cancer

Introduction: Trastuzumab with or without chemotherapy is the standard of care for patients with HER2+ metastatic breast cancer. The proposed mechanism of trastuzumab-induced regression of HER2+ tumors includes inhibition of tumor cell proliferation, potentiation of chemotherapy, and facilitation of immune function through antibody-dependent cell-mediated cytotoxicity. GM-CSF (Leukine) is a cytokine that mediates antibody-dependent cell-mediated cytotoxicity. We studied the feasibility and efficacy of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant, HER2+ metastatic breast cancer.Patients and Methods: Patients with measurable, HER2+ metastatic breast cancer that progressed after treatment with trastuzumab with or without chemotherapy were continued on trastuzumab alone at 2 mg/kg intravenous weekly. GM-CSF (250 μg/m2 subcutaneous daily) was added until the absolute neutrophil count (ANC) was greater than 10,000/mm3, then given every other day while the ANC was maintained below 10,000/mm3. Disease was restaged every 8 weeks. Treatment with trastuzumab and GM-CSF was continued until disease progression or intolerable toxicity.Results: Of 18 eligible patients with progressive HER2+ metastatic breast cancer, 17 (median age 48 yr, range 27–75 yr) were evaluable. Nine had hormone receptor–positive disease. The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens (trastuzumab with or without chemotherapy) for metastatic disease was 2 (range 1–5). One patient developed rapidly progressive disease 2 weeks after the start of study therapy and died soon after. The other 16 patients continued treatment until disease progression. No disease response was observed, but 5 patients (29%) had stable disease with a median duration of 15.8 weeks (range 10–53.9 weeks). Thirteen patients had grade 1 toxic effects; 6 patients, grade 2; and 2 patients, grade 3 (fatigue and muscle aches). The most common toxic effect was rash at the injection site, followed by skin rash, fatigue, and muscle aches. No grade 4 or irreversible toxic effect was seen.Conclusion: The addition of GM-CSF to trastuzumab alone in patients with trastuzumab-resistant, HER2+ metastatic breast cancer stabilizes the disease for a median duration of 15.8 weeks without causing any significant toxic effects in 29% of heavily pretreated patients. Its administration is simple, safe, and feasible. This regimen, trastuzumab and GM-CSF, needs further evaluation in combination with chemotherapy or other biological agents.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5103.

Effect of Trastuzumab and Chemotherapy on Circulating Tumor Cells in Patients with Poor Prognosis Metastatic Breast Cancer

Background. Trastuzumab has significant activity in HER2 neu amplified metastatic breast cancer (MBC). We hypothesized that it may selectively act against circulating tumor cells (CTC) in HER2-positiveMBC. We assessed the effect of trastuzumab-based regimens on CTC in HER2-positive MBC with poor prognosis (≥ 5 CTC).Patients and Methods. We retrospectively evaluated patients with poor prognosis MBC (baseline ≥ 5 CTC) treated with a first-line regimen consisting of trastuzumab+antimitotic agents in 11 HER2-positive patients not previously pretreated with trastuzumab, chemotherapy with antimitotic agents in 24 HER2-normal patients, and other chemotherapeutic drugs (mainly capecitabine) in other 16 HER2-normal patients. CTC were detected and enumerated using the CellSearch system (Veridex LLC, Warren NJ, USA). We evaluated the effect on CTC counts and on progression-free survival (PFS) and overall survival (OS).Results. At a median follow-up of 16 months (range, 4 to 48), 24 patients (47%) died. All 11 HER2-positive patients treated with trastuzumab+antimitotic agents had &lt;5 CTC during the treatment. Only 16 (67%) with HER2-normal MBC had &lt;5 CTC with antimitotic agents (p = 0.037), and 28 (70%) with other chemotherapeutic regimens (p = 0.048). No statistically significant difference was observed between patients treated with antimitotic agents and those treated with other chemotherapeutic agents (p = 0.73). There was no difference between patients receiving polychemotherapy and monochemotherapy (p = 0.73). The median PFS was 12 months in HER2-positive patients treated with trastuzumab+antimitotic agents compared with 7 months for those with HER2-normal (p = 0.09). The median OS was not reached (&gt;20 months) and 19 months (p = 0.034), respectively. The median PFS was 8 months in HER2-normal patients with ≥5 CTC and 4 months in those with &lt;5 CTC (p = 0.01). The median OS was not reached (&gt;17 months) and 9 months (p = 0.01), respectively.Conclusions. Trastuzumab is highly effective in patients with HER2-positive MBC with poor prognosis (≥ 5 CTC). Antimitotic agents and other chemotherapy agents did not show a similar effect in HER2-normal MBC. CTC might be useful in the monitoring of poor prognosis MBC patients undergoing therapy with trastuzumab.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3014.

Synergistic Effect of Lapatinib and the Class 1 HDAC Inhibitor SNDX-275 in Breast Cancer

Background: Inflammatory breast cancer (IBC) is a rare but aggressive form of primary breast cancer with high metastasis rates and poor survival outcomes in patients. Currently, no specific targeted therapy is available to improve patient outcomes, although agents (i.e. trastuzumab and lapatinib) targeting the human epidermal growth factor 2 (HER2) have shown promise in clinical trials. Histone deactylases (HDACs) represent another family of proteins for which inhibitors have been clinically validated and shown to inhibit proliferation of breast cancer cells in vitro and in vivo. In these studies we determined the single agent activity of the class 1 selective HDAC inhibitor entinostat (SNDX-275) in IBC cell models and whether SNDX-275 was synergistic with the HER2 targeted agent lapatinib.Methods: SNDX-275 activity was evaluated in SUM190, SUM149 and KPL-4 IBC cell lines using standard proliferation assays and compared to the non-IBC cell lines MDA-MB-231, SKBr3 and MCF-7. Apoptotic activity and cell cycle analysis were analyzed. SNDX-275 combination with lapatinib was initially determined in vivo in a HER2+ breast cancer model and subsequently in the SUM190, SUM149, KPL-4 IBC cells. For xenograft studies, athymic nude mice bearing human breast (BT474) tumor xenografts were treated with SNDX-275 at 15 or 30 mg/kg/day and lapatinib at 30 mg/kg/ 2xday or 75 mg/kg/ 2xday.Results: Significant anti-proliferative activity of SNDX-275 was observed in IBC (IC50, 250–500 nM) when compared with the non-IBC breast cancer cell lines MDA-MB-231, SKBr3, and MCF-7 (IC50 2–5 mM). Cell cycle analysis showed the onset of apoptosis in IBC cell lines (10%-17%); in the non-IBC cell lines, very little apoptosis occurred (0.8%–3.1%), although G1 stage arrest was seen in the non-IBC cell lines MDA-231 and MCF-7. The SNDX-275–induced apoptosis in IBC cell lines was dependent on caspase 9 rather than Caspase 8 cleavage indicating that the intrinsic apoptotic pathway is activated. The experiments with lapatinib demonstrated a significant benefit of the SNDX-275/lapatinib combination in both the BT474 xenograft study as well as the IBC cell lines tested. In the animal group that was treated with 15 mg/kg SNDX-275 plus 75 mg/kg lapatinib, synergistic effects were observed with tumor regression that was continued at least for 4 weeks after treatment was stopped. Similarly, synergistic anti-proliferative activity was found in almost all (4 of the 5) cell lines tested (SUM190, SUM149, KPL-4, and BT474). Investigation into the mechanism of SNDX-275–mediated apoptosis and the combined effects of lapatinib and SNDX-275 in IBC are under way. Our data demonstrate that HDACi as single agents and particularly in combination with HER2 targeted agents represent a promising new approach for clinical development in IBC breast cancer and patients with HER2-overexpressing breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3135.

Clinical Outcomes in Two Different Cohorts of Patients with Inflammatory Breast Cancer (IBC) Treated at the MD Anderson Cancer Center: The Experience of the Morgan Welch IBC Research Program and Clinic

BACKGROUND: Inflammatory Breast Cancer (IBC) is a rare but aggressive manifestation of primary breast cancer. Survival in patients with IBC is significantly lower than for non-IBC breast cancer patients. Appropriate diagnostic and treatment strategies provided by a specialized multidisciplinary team could impact the overall prognosis of the disease. We recently established an IBC research program and clinic including investigators from various disciplines solely dedicated to this disease. We sought to compare the characteristics and clinical outcomes of newly diagnosed IBC patients evaluated and treated using novel diagnostic and therapeutic approaches with an historical cohort of IBC patients treated at our institution.METHODS: We included 240 IBC patients treated at MD Anderson Cancer Center between January 1970 and August 2000. In this analysis we compared characteristics, 1 year progression free survival (PFS) and 1 year survival between the historic cohort and 47 patients diagnosed with IBC and seen at our IBC clinic between August 2007 and September 2008. The new patients are part of a prospective IBC registry. All of them had staging and monitoring with breast MRI and FDG-PET/CT. When indicated, they were treated with targeted therapies (e.g. trastuzumab and tipifarnib), that were not available for the patients in the old cohort. Descriptive statistics were used. Kaplan Meier product-limit method was used to calculate survival outcomes, groups were compare by log-rank test.RESULTS: Median age was similar in both cohorts (53 vs 51). In the new cohort 40% of the patients had evidence of distant metastasis at presentation. The most common sites were contralateral lymph nodes (26%), pleura (16%), bone (16%) and liver (11%). In the old cohort only 17% presented with stage IV. 38.7% of the new patients had Her2-neu amplified and 34%, triple receptor negative IBC. There was no difference in 1-year survival between the two groups (92.4% vs. 93.8%, p=0.637). For patients with stage III disease, the 1-year survival was 95% for both groups. The 1 year-PFS was 86.4% in the new cohort compared to 77.9% (p=0.43) in the old cohort. With a median follow up of 13 months, 51%of the patients in the new cohort are disease free and 87% are still alive.CONCLUSIONS: IBC is an aggressive but rare disease with poor prognosis. We have established a specialized IBC research program and clinic that introduces novel concepts and strategies in laboratory, imaging diagnostics and targeted therapies. This approach may accelerate our understanding of the biology, develop new therapeutic strategies and finally improve the outcome of IBC. Early results of this multidisciplinary approach show a modest, but not significant difference in outcome. We hope that with additional patients and longer follow-up a significant improvement in outcomes will become apparent.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5119.

Predictive Value of Circulating Tumor Cells (CTCs) in Metastatic Breast Cancer Patients Treated by Bevacizumab-Based Therapy

Background:Circulating tumor cells (CTC) are involved in cancer dissemination and are an independent prognostic factor in metastatic breast cancer (MBC). Antiangiogenic, bevacizumab-based chemotherapy improves response rate and progression free survival in patients with metastatic breast cancer (MBC), without impact on overall survival. Preclinical data suggest the possibility of increased metastatic potential of tumor cells pretreated by anti-angiogenic therapy (Ebos et al. Cancer Cell 2009,15: 232–9). The aim of this study was to determine the prognostic value of CTC in MBC patients treated by bevacizumab-based therapy.Patients and Methods: This retrospective study included 48 MBC treated with bevacizumab combined chemotherapy regimens and 46 patients treated with chemotherapy alone between January 2004 and December 2008 at M.D.Anderson Cancer Center. CTCs were detected and enumerated before patients started therapy using the CellSearch™ system (Veridex, LLC, NJ, USA). Progression free survival (PFS) and overall survival (OS) were calculated from the date of CTC measurement, estimated by the Kaplan-Meier product limit method, and compared between groups with the log-rank test.Results: At a median follow up of 10.1 months (range: 1-26 months), 22 patients (45.8%) had died. The estimated medians of PFS in bevacizumab-treated patients were 8.1 vs. 5.2 months (p = 0.42) in patients with baseline &lt; 5 CTCs vs. ≥ 5 CTCs. Moreover, the OS for the two subgroups were 18.3 vs. 12.4 months (p = 0.41), respectively. Twenty-three patients had CTC measurements at the time of progression. Median CTC counts at baseline and at time of disease progression were 6 (range: 0-230) and 7 (range: 0-359) respectively in the bevacizumab-treated group. The median CTC counts in the control group at same time points were 7 (range: 0-724) and 2 (range:0-999), respectively. Thirteen (56.5%) and 12 (52.2%) patients had CTC ≥ 5 at baseline and at time of disease progression in bevacizumab-treated group compared to CTC counts of 24 (52.2%) and 17 (37%) in control group treated with chemotherapy without bevacizumab. Post progression overall survival in patients with CTC &lt; 5 and CTC ≥ 5 measured at time of disease progression were 11.0 and 10.4 months (p = 0.36), in the bevacizumab treated group vs. 27 and 12.4 months (p = 0.04), in the control group respectively.Conclusion: Our data support the prognostic value of CTC measured before therapy in MBC. The detection of higher CTC counts at time of disease progression and the limited prognostic value of CTC after failure of bevacizumab-based chemotherapy although intriguing, warrants further prospective investigations. Moreover, a comparison between the differential effects of monoclonal antibodies and tyrosine kinases inhibitors on CTCs detection and monitoring will better clarify the role of specific targeted therapies on micrometastatic disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3013.

Immune Profile of Inflammatory Breast Cancer Patients

Background: Inflammatory breast cancer (IBC) is characterized by an acute inflammation of the skin of the affected breast due to blockage of the dermal lymphatics by tumor emboli. Cytokines and chemokines affect the migration of tumor cells and immune cell function that regulates the pathogenesis of IBC. Preliminary data suggest that sera of IBC patients contain several inflammatory cytokines and chemokines capable of regulating innate and adaptive cellular immune responses. Since there is a paucity of data on the characteristics and function of immune cells of IBC patients, we determined the immunophenotype and cytokine production by T cells and dendritic cells.Methods: From October 2008 through May 2009, peripheral blood (PB) from 34 IBC patients (18 non-metastatic and 16 metastatic), 18 non-IBC patients and 24 healthy donors (HD) were analyzed to determine the immunophenotype of T-cell subsets, activated and regulatory T-cells, B-cells, natural killer cell subsets (NKC), and dendritic cell (DC) subsets. Additionally, we assessed the ability of T-cells and DCs to synthesize cytokines following activation through the T-cell receptor (TCR) and toll-like receptors (TLR), respectively. The Kruskal-Wallis and Mann-Whitney U tests determined the differences between IBC patients, non-IBC patients, and HD.Results: IBC and non-IBC patients were well-matched in terms of ER, PR, Her2, high-grade tumor, tumor size, and menopause status. Both IBC and non-IBC patients had significantly fewer lymphocytes, total T-cells (CD3+), T-helper (CD4+), T-cytotoxic/suppressor (CD8+), and B (CD19+) than HD (all p &lt; 0.01). Non-IBC patients had a significantly lower CD4/CD8 ratio than HD (p = 0.016) while IBC patients had significantly fewer T-regulatory (CD4+CD25hiCD127-) cells than HD (p = 0.02) and non-IBC patients (p &lt; 0.05). With respect to innate immunity markers, IBC patients also had significantly lower percentages of ADCC/NK (CD16+CD56+, p = 0.034) and non-exhaustive NK (CD56+CD57+, p = 0.02) than HD and a significantly higher percentage of non-ADCC/NK cells than non-IBC patients (p = 0.03). Non-IBC patients and HD had similar innate immunity markers. Even though all groups had similar percentages of myeloid (mDC) and plasmacytoid (pDC) dendritic cells, mDC of IBC patients displayed a higher level of constitutive activation than non-IBC with increased expression of CD40 and CD80, and decreased CCR5 expression. IBC patients had more mDC that constitutively produced TNF-a (p 0.041) and IL-10 (p = 0.029) than HD, and more mDC than non-IBC patients that produced IL-10 (p = 0.028).Conclusion: The immune profile of patients with breast cancer suggests multiple abnormalities involving T-, B-, NK- and dendritic cells. Furthermore, IBC patients exhibited constitutive immune activation as measured by increased expression of co-stimulatory receptors (CD80, CD40) and constitutive production of TNF-a and IL-10 by mDC as well as fewer T-regulatory cells. Taken together, these preliminary data suggest that IBC patients are more likely than non-IBC patients to have a dysregulated immune function. Additional studies on T-cell activation and function are warranted to better understand factors associated with host defense mechanisms of IBC patients and possible therapeutic strategies to restore immune function.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4129.

Characterization of Metastatic Breast Cancer Patients with Non-Detectable Circulating Tumor Cells

Background: Circulating tumor cells (CTC) are independent predictor of progression free and overall survival in metastatic breast cancer patients, with superior prognosis for patients with CTC &lt;5 per 7.5mL of peripheral blood. However, 30-50% of patients have non-detectable CTC. The aim of this study was to assess the prognostic factors in MBC patients with non-detectable CTC.Methods: This retrospective study included 271 MBC patients evaluated between January 2004 and December 2007. Median age of patients was 56 years (range: 23-82 years). CTCs were enumerated before patients started a new line of treatment using the CellSearchTM. Overall survival (OS) was calculated from the date of CTC measurement, estimated by the Kaplan-Meier product limit method, and compared between groups with the log-rank test.Results: Median CTC count was 2 (range: 0-1780) per 7.5 mL. CTCs were not detected in 99 (36.5%) patients, while 112 (41.3%) patients had CTC ≥ 5. Median OS for patients with 0 CTC; 1-4 CTC and ≥ 5 CTC was 29.3; 26.4; and 19.4 months (p = 0.04), respectively. Patients with brain metastasis have the highest probability of non-detectable CTC (71.4% vs. 33.6%; p = 0.001), while patients with bone metastasis are more likely to have CTC ≥ 1 (48.2% vs. 31.8%; p = 0.01). There was no association between other tumor characteristics (ER, PR, HER2, number and localization of tumor metastasis) and non-detectable CTC status. Patients with CTC = 0 have non-significantly better OS compared to patients with CTC ≥ 1 (29.3 vs. 23.3 months; p = 0.09) and have superior survival in all but one analyzed subgroups; only inflammatory breast cancer (IBC) patients with CTC = 0 have inferior OS compared with patients with CTC ≥ 1 (26 vs. 37 months; p = 0.67). In a subgroup of patients with non-detectable CTC, triple negative MBC has the poorest survival (median OS = 18.8 months), while hormone receptor positive MBC, without visceral metastases and non-inflammatory breast cancer has the best survival (median OS = 36.9 months). In multivariate analysis, hormone receptor status and line of therapy were only independent prognostic factors for OS in patients with non-detectable CTC (Table 1).Conclusion: Patients with non-detectable CTC before start of new line of therapy comprise a heterogeneous group of patients with substantially different prognosis. Triple negative and IBC patients represent poor prognosis subgroups. These data suggest heterogeneity of microscopic disease in advanced cancer and indicate the need to investigate combining additional detection technologies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3006.

Brain Metastases in Women with Inflammatory Breast Cancer (IBC): Incidence, Treatment and Outcome

Background: Brain metastases are an uncommon metastatic recurrence site in breast cancer with a median incidence of approximately 6% in unselected populations. Inflammatory breast cancer (IBC) is an aggressive disease associated with dismal outcome. The purpose of this study was to determine the incidence of and survival following brain metastases among women with IBC.Material and Methods: Two hundred and six women with newly diagnosed stage III or IV IBC diagnosed between the period of between 2003 and 2008 were identified in a prospectively maintained IBC database at the MD Anderson Cancer Center. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for the development of brain metastases. Survival was computed using the Kaplan-Meier product limit method.Results: Median follow-up was 20 months. Eighty three (40.3%) women had de-novo stage IV disease and 123 (59.7%) had stage III disease at diagnosis. Thirty-three (16%) patients developed brain metastases with a cumulative incidence at 1 and 3 years of 2.7% and 22% respectively. Eleven (5.3%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 1 and 3 years of 1.6% and 6.7% respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases, including HER-2 status. Median overall survival for the whole cohort was not reached. 3-year overall survival for the whole cohort was 78% (95% CI 69%-86%). Median survival following a diagnosis of brain metastases for all women who developed brain metastases or those who developed brain metastases as the first site of recurrence was 6 months.Conclusion: In this single-institutional study, women with IBC demonstrated a high early incidence of brain metastases associated with poor survival. As such IBC may be an ideal cohort to target screening procedures for brain metastases and/or enrollment of these women in clinical trials evaluating additional adjuvant preventive strategies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2102.

Role of the prostaglandin receptor EP3 in regulating vasculogenic mimicry of inflammatory breast cancer

Abstract #2127

Background: Inflammatory breast cancer is an aggressively angiogenic, metastatic and lethal variant of breast cancer. One of the characteristics of aggressive tumors types such as IBC is the ability of tumor cells to undergo vasculogenic mimicry (VM), which is the formation of organized capillary like structures in vitro and in vivo much like endothelial cells, providing a conduit for oxygen and nutrients to reach hypoxic and nutrient deprived tumor cells that have outgrown their adjacent vascular supply. Using genomic and proteomic profiling as well as Western blotting, immunohistochemistry, invasion assays using the modified Boyden chamber assay as well as digital imaging, we evaluated the signal transduction pathways involved in regulating proliferation, invasion, and VM by IBC tumor cells.&#x2028; Results: We found that cyclooxygenase-2 (Cox-2), which produces the bioactive lipid, prostaglandin E2 (PGE2) is one gene that is highly expressed IBC tumor cell lines, SUM149 and SUM190. The biological activity of PGE2 occurs via binding of PGE2 to one of 4 members of a G protein coupled receptor family, designated as the EP receptors, EP1, EP2, EP3 and EP4. Western blot analysis and immunochemistry revealed that EP3 receptor protein is produced at very high levels by both IBC tumor cell lines to a significantly (p&lt;0.05) greater extent than either human MCF-7 or MDA-MB-231 non-IBC breast tumor cells. Since EP3 is known to be an inhibitory prostanoid receptor, we evaluated the dose dependent effects of the EP3 agonist, sulprostone, on proliferation, invasion, and VM. Sulprostone [0.1, 1, 10 and 100 μm] inhibited proliferation of SUM149 and SUM190 IBC cells in a dose and time dependent manner to a significantly greater extent (p&lt;0.01) than MCF-7 or MDA-MB-231 breast tumor cells. Sulprostone inhibited invasion of SUM149 IBC tumor cells, with no effect on invasion of a basement membrane by the MDA-MB-231 human non-IBC breast tumor cells. SUM149 IBC tumor cells undergo VM, which was completely inhibited by 10 μM sulprostone at 24 hrs, as visualized by Periodic Acid Schiff (PAS) staining and digital imaging. The ability of sulprostone to completely inhibit VM occurred in conjunction with inhibition of production of laminin 5-γ2 fragments and matrix metalloproteinase-2 (MMP-2) activity. Studies are currently underway to determine the in vivo effect of sulprostone on IBC tumor growth, VM, and metastasis of SUM149 IBC xenografts.&#x2028; Discussion: These results suggest that targeting EP3 may provide a selective advantage for abrogating not only proliferation, and invasion but also vasculogenic mimicry that is a key component of the rapid angiogenic program observed in IBC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2127.