Citations

Abstract Background The BRCA 1 tumour suppressor gene is mutated in a significant proportion of hereditary breast cancer cases. Additionally, downregulation of BRCA1 mRNA and protein expression is reported in approximately one third of sporadic breast cancers. BRCA1 is strongly implicated in the maintenance of genomic stability by its involvement in multiple cellular pathways including: DNA damage signalling, DNA repair, cell cycle regulation, protein ubiquitination, chromatin remodelling, transcriptional regulation and apoptosis. To date, gene expression profiling has identified: (1) at least five breast cancer subtypes and (2) that BRCA1 mutant tumours segregate with basal-like breast cancers. These studies also provide evidence that breast cancers with germline mutations in BRCA1 are different from non BRCA1-related tumours. The main aim of this study is to investigate the underlying biology of BRCA1-mutated breast cancer. Methods Extensive gene expression profiling and data analysis were performed on a cohort of 70 FFPE (Formalin Fixed Paraffin Embedded) derived BRCA 1 mutated breast tumours and matched sporadic controls using the Almac Breast Cancer DSATM research tool. Functional analysis was performed with DAVID and METACORE. Validation of gene targets was performed by qRT-PCR and Western blotting. Results A list of differentially expressed transcripts has been derived from the comparison of these BRCA1 mutant breast tumours and matched sporadic controls. Functional analysis of this gene list has identified the key genes and molecular pathways that are deregulated in these tumours. BRCA1 deficiency was associated with deregulation of pathways involved in: (1) immune response, (2) metastasis and invasion, (3) cytoskeletal remodelling, (4) spindle assembly and chromosome separation, (5) apoptosis and survival. Validation of the key genes underlying this BRCA1-deficient breast cancer profile has been performed. Conclusions This approach has revealed a set of transcripts that could potentially be used to identify both hereditary and sporadic breast cancer patients with BRCA1- deficiency. The ability to perform gene expression profiling from FFPE derived breast tissue could also have significant clinical application. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-04-02.

Abstract INTRODUCTION: Surgical site infection (SSI) is a problematic cause of morbidity following breast/axillary surgery. The breast/axilla has a higher rate of SSI than expected for clean wounds. We evaluated risk factors associated with SSI after breast/axillary operations. Methods: A retrospective review of breast/axillary procedures from July 2004 to July 2006 was performed. SSI was defined using Centers for Disease Control and Prevention criteria, including cases with cellulitis as the only criterion of infection. Data collected included patient demographics, BMI, surgical procedure, ASA class, antibiotic use, drains, and prior radiation (RT). RESULTS: We identified 389 patients who underwent 678 procedures. Thirty-seven SSI (5.5% of procedures) were identified, of which 24 (65%) had only cellulitis. Median time from surgery to SSI diagnosis was 9 days (range 2-112), with 81% occurring in the first 30 days. Univariate analysis identified prior RT, BMI, type of procedure, operative time, use of drain, and postoperative seroma to be associated with SSI (all P<0.05). With multivariate analysis, procedure type remained significant overall (p=0.04). Specifically, mastectomy with sentinel lymph node biopsy (SLNB) and modified radical mastectomy remained significantly associated with higher risk of SSI, with hazard ratios (HR) of 6.3 and 13.5 fold respectively compared to SLNB alone. Seroma (HR 9.0, 95% CI 2.7-29.3), prior RT (HR 3.4, 1.2-9.9), and BMI >=30 (HR 3.1, 1.6-6.2) also remained significantly associated with SSI. CONCLUSION(S): SSI are more frequent after breast/axillary operations than other clean wounds and are associated with prior RT, obesity, more extensive and longer procedures, and postoperative seroma. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-10.

Abstract Background: Trastuzumab (H) improves disease-free survival (DFS) in patients (pts) with HER2 positive breast cancer (BR Ca) when used with adjuvant chemotherapy. We herein compare the rates of local regional recurrence (LRR) in pts randomized to adjuvant chemotherapy with or without adjuvant H. Methods: The phase 3 randomized trial NCCTG N9831 enrolled 3505 pts with high risk HER2 positive Br Ca to evaluate the effect of adjuvant H on DFS. Pts were randomized to either doxorubicin (A) and cyclophosphamide (C) followed by paclitaxel (T); or AC→TH→H. RT was given concurrently with H after ACT chemotherapy. Pts analyzed underwent lumpectomy (L) + radiotherapy (RT), mastectomy (M) alone, or M+RT. All pts underwent sentinel lymph node biopsy alone and/or axillary dissection. 2816 pts were eligible for competing risk analysis of LRR as a first event (competing risks were distant recurrence, contralateral Br Ca, second primary cancer, or death). Median follow-up is 5.3 years. Results: Primary breast therapy included L+RT 1062 (38%), M 711 (25%), and M+RT 1043 (37%). Axillary dissection was performed in 90% of pts but less frequently with L+RT (83%) compared to M (88%) or M+RT (98%), chi-sq P<0.001. Stage at presentation was I 41%, II 51%, and III 8% with a significant greater proportion of higher stage pts undergoing M+RT, chi-sq P<0.001. Overall the 5-year LRR rate was 4.1% (95% CI 3.5-4.9%) and similar among the treatment groups: L+RT 4.7% (95% CI 3.6-6.1%), M 3.5% (95% CI 2.4-5.1%), and M+RT 2.3% (95% CI 1.6-3.4%). Among pts with a LRR, 66% were local recurrence only, 11% were local-regional, and 23% were regional only. In the L+RT patients with a LRR, the corresponding rates were 74%, 7%, and 19%, respectively. In the M patients with a LRR, the corresponding rates were 40%, 23%, and 37%, respectively. In the M+RT patients with LRR, the rates were 79%, 4%, and 17%, respectively. H is associated with a non-statistically significant reduction in the risk of LRR for pts who receive L+RT or M+RT (Table 1). No such trend was seen in the M alone group but the number of events was low. Table 1. LRR According to Local and Adjuvant Treatment Groups Conclusion: The LRR as the first reported site of failure was low with a median 5. 3 year follow-up. Adjuvant H was associated with a trend of lower LRR in the pts treated with L + RT or M+RT. This observation suggests an additive effect of RT and H on LRR that warrants further investigation. The small number of local-regional events in this one randomized trial supports further investigation of LRR across other adjuvant trastuzumab trials. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-13-02.

Abstract Ductal carcinoma in situ (DCIS) of the breast is a heterogenous group of proliferative cellular lesions that have the potential to become invasive. Very little is known about the molecular alterations involved in the progression from DCIS to invasive ductal carcinoma (IDC). Heparan endosulfatases HSulf-1 and -2 catalyze or edit sulfate moieties on heparan sulfate proteoglycans and have been implicated in modulating heparin binding growth factor signaling. Several studies have suggested that while expression of HSulf-1 is down-regulated and is considered a tumor suppressor gene, expression of HSulf-2 is over-expressed in primary breast tumors and cell lines. However, the role of HSulf-2 in breast tumorigenesis is poorly understood. Here we have evaluated the effect of HSulf-2 in an in vivo model of breast cancer progression (MCF10DCIS.com). These cells form comedo type DCIS and progress to IDC when transplanted in immune-deficient mice and therefore are an ideal model to study breast cancer progression. Methods: Stable clones depleted of HSulf-2 in MCF10DCIS.com cells were generated and injected into mouse mammary fat pads with non-targeted control shRNA clones (NTC) as controls. HSulf-1, HSulf-2, smooth muscle actin immunostaining and H&E staining was perfromed at weeks 3, 5 and 7. Matrixmetallo Protease (MMP) expression by real time PCR was evaluated at Weeks 3 and 5 in both groups. Results: A significant reduction in tumor growth was observed in HSulf-2 depleted clones compared to NTC clones (p=<0.01). HSulf-2 immunohistochemical staining showed distinct pattern of staining localized to ductal lesions as well as stromal (myoepithelial and myofibroblasts cells). In contrast, the closely related family member, HSulf-1 expression was restricted largely to stromal and myoepithelial layer in ductal lesions. While HSulf-2 staining remained intense from weeks 3 to 7, HSulf-1 expression was diminished during the same time period. In NTC clones, ductal like lesions were observed by week 3 with disruption of the basement membrane and appearance of invasive phenotype by weeks 5 and 7. In contrast, HSulf2 knockdown xenografts showed retention of ductal like structures even at week 5 and retention of basement membrane (p=<0.05). Additionally marked necrotic areas were also observed in HSulf-2 silenced clones. Previous studies have shown that the malignant epithelium induces the development of the stroma necessary for the development of invasive phenotype. Consistent with this observation, we demonstrated decreased MMP expression in xenografts derived from HSulf-2 depleted clones compared with NTC xenografts (p=<0.05). Conclusions: Our data suggest that HSulf-2 may play an important role in the transition from DCIS to an invasive phenotype (IDC) potentially by up regulating MMP expression and activity. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-12.

Abstract Lymphedema (LE) is a common complication of cancer treatment, and has been identified as the number one issue by breast cancer survivors with incidence as high as 70%. Given the long-term survivorship of these women, LE is a widely prevalent condition. Irradiation of axillary and supraclavicular lymph nodes increases a patient's risk of LE onset and progression by as much as 2-fold. It is anticipated that a more individualized approach to post-surgical irradiation of breast cancer patients may reduce radiation-induced lymph node (LN) damage without sacrificing control rates, although it is noted that a definitive radiation exposure threshold below which LNs physiological integrity will be preserved is currently lacking. To identify the locations of the small, non-pathological but physiologically relevant LNs which drain the arm after breast cancer surgery and incorporate them into radiation planning, filtered 99mTc sulfur colloid (TcSC) was administered and a SPECT-CT scan was acquired for 22 patients immobilized in the treatment position. These images were registered with the Radiation Oncology planning CT scan, and draining LN were contoured automatically using a threshold of 50% maximum intensity. Two treatment plans were generated for each patient, one per routine clinical practice (STD) and the other (MOD) with treatment fields modified to minimize dose to the LNs visible on SPECT/CT images while ensuringthat ≥50Gy or biologic equivalent is delivered to target tissues. 53 draining LN were identified, 54% of which were inside the STD plan fields but could be blocked in the MOD plan fields. 62% of LN in the STD plans vs. 17% in the MOD plans receiving a mean of ≥10Gy, and 27% in the STD plans vs. 6% in the MOD plans receiving a mean of ≥40Gy. Patient-specific LN dose reduction can be achieved through integration of SPECT/CT images into the radiation planning process. These patients will be followed for the development of LE, to estimate an exposure threshold below which LN preservation is assured. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-20.

Abstract Background Local recurrence after breast conservation surgery (BCS) varies with clinical risk factors. The aim of this study was to evaluate how local recurrence rates vary by patient age at time of BCS. Methods With IRB approval, all patients undergoing BCS for primary breast cancer between 1988 and 2001 at Mayo Clinic, Rochester were identified. Patients receiving neoadjuvant chemotherapy were excluded. Local recurrence-free survival rates were estimated using the Kaplan-Meier method. Associations with local recurrence-free survival were evaluated using log-rank tests and Cox proportional hazards regression models. Results 3,075 patients underwent 3,143 BCS between 1988 and 2001. Mean age at BCS was 61 years (range 21-98). There were 177 (5.6%) patients aged <40, 496 (15.8%) 40-49, 763 (24.3%) 50-59, 803 (25.6%) 60-69, and 904 (28.8%) who were 70+ years old at time of surgery. At last follow-up, 214 patients (6.9%) experienced a local recurrence at a median of 3.4 years following BCS (range 0.1-14.4). Median follow-up for patients who did not experience a local recurrence was 8.7 years (range 0.0-20.2). The 5-year local recurrence-free survival rate was 95.0%. The frequency of local recurrences by age group were as follows: age <40 — 11.9%; age 40-49 — 5.9%; age 50-59 — 5.9%; age 60-69 — 7.6%; age 70 and older — 6.4%. The 5-year local recurrence-free survival rates for these age groups were 90.0%, 95.4%, 95.6%, 95.4%, and 94.7%, respectively (p=0.041; log-rank test). On univariate analysis, patients <40 years old were nearly twice as likely to experience a local recurrence following BCS compared with patients DCIS was associated with an increased risk of local recurrence compared with T1, T2, T3, or T4 disease (HR 2.25; P<0.001). Factors associated with a decreased risk of local recurrence on univariate analysis included ER positivity (HR 0.46; P<0.001), PR positivity (HR 0.60; p=0.001), adjuvant radiation (HR 0.48; p=0.007) and endocrine therapy (HR 0.65; p=0.012). Multivariate analysis of patients with complete data (n=2126) demonstrated that age <40 and node positivity were associated with an increased risk of local recurrence, while ER positivity, adjuvant radiation and endocrine therapy were associated with a decreased risk of local recurrence. Multivariable analysis of local recurrence after BCS Conclusion Risk factors for local recurrence after BCS include young age, node positivity, ER and PR negativity and absence of adjuvant radiation and endocrine therapy. Patients under age 40 are at increased risk of local recurrence following BCS for breast cancer. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-10-02.

Abstract MN Background: Breast cancer is the second leading cause of cancer death of women worldwide. One of the major challenges for a better prognosis of breast cancer patients is the ineffectiveness of chemotherapy and drug resistance. To investigate the mechanisms of drug resistance, resistant cancer cell lines have been established with various anticancer agents. We found that FASN, an important metabolic enzyme overexpressed in aggressive carcinomas, is t responsible in part for the drug resistance phenotype of breast cancer cells. Our findings show that blockage of FASN augments the cytotoxicity of the anti-mitotic drug Taxol in breast cancer cells. Moreover, C75 and Taxol have a synergistic effect both drugs are combined. The in vivo effect of C75 and Taxol and the mechanism by which blockage of FASN sensitizes the cells to chemotherapy are unknown. Material and Methods: In this study first we show the effect of C75 plus Taxol in breast tumor growth. BT474 cells were injected into the mammary fat pad of nude mice to generate the tumors. When the tumors were measurable we treated the mice with C75, Taxol or with a combination of both drugs. Second we studied the lipid rafts disruption after treatments by sucrose gradient and immunofluorescence. Results: We found that C75 plus Taxol extensively inhibited the tumor growth 9 fold and reduced the tumor size in 4 fold comparedn to the control mice (no treatement). In comparison C75 alone reduced the tumor growth in 1.5 fold only; and Taxol 2.5 fold compared to the control mice. These results show for first time that blockage of FASN (with C75) sensitizes breast cancer tumors to Taxol treatment in vivo. In addition, we studied the possible mechanism involved in the sensitization of breast cancer cells to Taxol by FASN blockage. Previous studies reported that blockage of FASN or Taxol treatment decrease the sphingolipids synthesis. Sphingolipids and cholesterol are the most abundant fatty acid in the lipid rafts in the plasma membrane. Disruption of lipid rafts has been shown to induce apoptosis in different carcinoma cell lines. Based in these findings, we studied lipid rafts in BT474 cells treated with C75, Taxol or combination of both with sucrose gradient and immunofluorescence microscopy. Discussion: Our results show that C75 and Taxol disrupt the lipid rafts. Thesefindings show that FASN is a new mechanism of drug resistance and may be an ideal target for chemosensitization in breast cancer chemotherapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-03-01.

Abstract Background: Ongoing phase III trials are comparing accelerated PBI around the lumpectomy site to standard whole breast irradiation in early stage breast cancer. Recent studies have questioned the late toxicity from PBI delivered with 3DCRT. We evaluated late toxicity on patients (pts) treated on RTOG 0319. Methods:52 pts with stage I-II breast cancer, ≥3 cm, negative margins, and < 3 nodes positive were treated with 3DCRT PBI and received 38.5 Gy in 10 BID fractions over 5 days. Median follow-up was 5.3 years (min-max: 1.7-6.4 years). Five pts were deceased at 5 years. NCI CTCAE v3.0 was used to grade adverse events (AEs). At 3 years, 50 pts were available for AE reporting or late toxicity assessment. Results: The treatment-related AEs were primarily grade 1 36.5%, 50% grade 2, and only 3 (5.8%) pts had grade 3 AEs. The grade 3 AEs in these pts were radiation dermatitis, skin fibrosis, telangectasia, and myositis. No baseline self-assessment of breast appearance is available. Patient self-assessment of breast appearance and satisfaction was available in 45 (87%) pts at 1 year and 36 (72%) at 3 years. At 1 year, 82% self reported excellent/good breast appearance and at 3 years, 64%. Pts who reported < excellent/good breast appearance had significantly more grade ≥2 skin AEs (telangectasia, skin atrophy, hyperpigmentation, erythema, skin fibrosis, radiation dermatitis, and breast or nipple/areolar deformity). At 3 years, 31 of 36 pts were satisfied with their treatment, but all 36 would choose 3DCRT PBI again over standard breast RT. Treatment factors were evaluated to establish correlation with patient reported breast appearance. Preliminary observations suggest surgical bed volume, PTV volume, number of beams used, and possible use of bolus are associated with patient reported outcomes (PRO). Surgical factors impacting PRO were not collected. Conclusions: The majority of pts were satisfied with their treatment results at 3 years and would all choose to have 3DCRT PBI again. With a median of 5.3 years, the rate of grade 3 AEs is low. Technical factors from this phase II trial were modified for the phase III NSABP B-39/RTOG 0413 trial, in which bolus is not allowed and both target volumes and required coverage were modified, increasing expectation of improved PRO. Supported by RTOG U10 CA21661, CCOP U10 CA37422 and ATC U24 CA 81647 NCI grants. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-15-07.

Abstract In the Breast International Group (BIG) and North Central Cancer Treatment Group (NCCTG) co-led phase III adjuvant breast cancer trial, ALTTO (Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation), two central laboratories, the European Institute of Oncology (IEO; Milan, Italy) and Mayo Clinic (Rochester, MN), are responsible for confirming the human epidermal growth factor receptor-2 (HER2), estrogen receptor α(ER), and progesterone receptor status of the primary breast tumors for the Rest of World (excluding China, which conducts a separate central review) and North American patients, respectively, prior to patient study entry. As of December 2009, discordance in HER2 and ER testing between local and central laboratories was observed by both central laboratories. For IEO, 14.5% of 8,037 HER2 cases locally positive [by either immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH)] were not able to be confirmed as centrally positive; whereas for Mayo, 5.8% of 412 HER2 cases locally positive were not able to be confirmed as centrally positive (Table 1). Central and local IHC ER discordance was 12.1% and 11.7% for 9,021 IEO screened cases and 419 Mayo screened cases, respectively (Table 2). In particular, IEO observed more false-positive (locally positive/centrally negative) HER2 findings than Mayo and Mayo observed more false-positive ER findings than IEO. Purpose: Motivated by the above findings, we launched a ring study to assess whether the central lab results of a subset of local/central discordant ALTTO cases could be confirmed in the other central lab. Methods: IEO and Mayo exchanged and retested a subset of FFPE breast tumors collected in ALTTO. IEO sent 20 HER2 false-positive, 5 ER false-positive, and 5 ER false-negative (locally negative/centrally positive) ALTTO breast tumors to Mayo. Mayo sent 5 HER2 false-positive, 20 ER false-positive, and 5 ER false-negative ALTTO breast tumors to IEO. IEO and Mayo performed IHC for ER according to their own methodology: DAKO cocktail of ER 1D5 and 2.123 monoclonal antibodies and monoclonal ER 1D5 antibody, respectively. The two laboratories performed IHC for HER2 according to the HercepTest® manufacturers’ instructions (Dako, Carpenteria, CA) and FISH for HER2 using the PathVysion HER2 DNA probe kit and the HER2/centromere 17 probe mixture (Abbott Molecular, Des Plaines, IL). Results: IEO and Mayo confirmed the central HER2-negative result in 100% of 25 cases. Analyses of ER are ongoing and ER results will be presented. Conclusions: In this subset of patients, enrollment ineligibility did not change when HER2 testing was performed by either IEO or Mayo Clinic central laboratories. Table 1. HER2 Local/Central Lab Results Table 2. ER Local/Central Lab Results Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-36.

Abstract Background: The MA.17 study showed that extended adjuvant endocrine therapy with letrozole (LET) after completing 5 years of tamoxifen (TAM) markedly reduced the risk of recurrence in women with ER+ early stage breast cancer and improved overall survival in women presenting with node +ve disease. The HOXB 13:IL17BR gene expression ratio (signature) has been shown to predict outcome in breast cancer patients treated with adjuvant tamoxifen monotherapy and provides additional information beyond that from known positive (ER and PR) and negative (Her-1 and Her-2) predictors of responsiveness to tamoxifen in node-ve women. We report a case control evaluation of the Breast Cancer Index (BCI; bioTheranostics, Inc.), which combines the HOXB13 and IL17BR twogene and the molecular grade index (MGI) gene expression signatures, with respect to distinguishing which patients are at risk of late recurrences and who would respond to extended endocrine therapy with LET. The prognostic and predictive utility of quantitative immunofluorescence of ER, PR, Her-2, tumor aromatase, COX-2, GATA3 and Nat1 in the TAM-PLACEBO and the TAM-LET cohorts will also be evaluated and compared to results derived by standard immunohistochemistry. Methods: FFPE tumor blocks were collected from patients who experienced a breast cancer recurrence up to unblinding of MA.17. Controls were matched 2:1 for age, tumor size, lymph node status, and prior chemotherapy, and were all disease free for longer than cases. All cases were reviewed for standard histopathology by two independent pathologists. RNA was extracted, amplified, converted to cDNA and subjected to RT-PCR with primers and probes to HOXB13, IL17BR, BUB1A, CENPA, NEK2, RACGAP1 and RRM2. ER, PR HER1, HER2, COX2, Aromatase, GATA3 and NAT1 will be analyzed by routine IHC techniques and by immunoflourescent Automated Quantitative Analysis (AQuA). Results: 105 cases and 210 matched controls are available for evaluation. All sections are under review and tissue microarrays have been performed on all cases and controls. Detailed results on the BCI and ER, PR, Her-2 will be available at the SABCS. Discussion: MA.17 has shown that extended adjuvant endocrine therapy after tamoxifen is effective at preventing disease recurrence given for an additional 5 years. Numerous clinical trials are exploring whether extending AIs will show this benefit, and there is an increasing need to improve the therapeutic index by distinguishing those at risk from those who are not. It is also important to determine which patients will benefit from the therapy and which will recur without benefit. The latter patients could be triaged to clinical trials of novel therapies to overcome endocrine resistance. This study will help to define these issues and pave the way for more effective selection of specific patients for adjuvant endocrine strategies. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-26.