Distinct multiethnic genome-wide alterations in breast cancer using paraffin embedded samples: preliminary analysis

Abstract #2024

Background and Rational: Ethnic-specific disparities in breast cancer (BC) stage of presentation and survival rates are well documented. To further investigate possible ethnic-specific genetic contributions to these disparities, we are completing gene expression profiling studies in a multi-ethnic cohort consisting of thirty “Triple Negative” BC patients [10 each African-American (AA), Hispanic (His) and non-Hispanic white (Cauc) women] matched for age of diagnosis and hormone receptor status. The overall study aim is an increased understanding of the biological basis of ethnic-specific BC disparities, leading ultimately to individualized, ethnic-specific diagnostic and therapeutic approaches. Two immediate study goals are to demonstrate the utility of FFPE samples in obtaining consistent, reproducible data from gene expression arrays, and secondly, to identify differentially expressed genes between tumor and normal tissue that are common or unique among the three ethnic groups. Methods: Pathology specimens were freshly cut from FFPE blocks and marked by a pathologist as to normal vs. tumor tissue. RNA isolation, labeled cDNA preparation, and hybridization of tumor and normal cDNAs to a breast cancer focused gene expression microarray (Breast Cancer DSA Research Tool) was performed by Almac Diagnostics. Each patient was self-matched (tumor vs. normal tissue) for gene expression studies. Results: Using 36 matched tumor and normal FFPE samples from 18 patients, approximately 17516 transcripts were detected on the Breast Cancer DSA with intensity significantly greater than background. For normal and tumor tissue samples, 9399 and 10,296 transcripts respectively, were detected in all three ethnic groups. Importantly, a subset of transcripts (hundreds to one thousand) was detected in only one or two ethnic groups. Using two-way ANOVA (disease state and ethnicity), a subset of 6479 transcripts was identified with p-value less than 0.01 in the statistical test and was selected and further used in data quality control. Data QC indicated that patient samples clustered well with respect to both ethnicity and normal versus tumor tissue. Additional analytical methods included K-means 2-Dimensional clustering and Principal Component Analysis. From these analyses, we identified ethnic-specific expression patterns in the matched normal and tumor tissue samples. We are completing these studies by increasing sample size and matching for stage of diagnosis, mapping clusters of differentially-expressed genes in pathway analysis, and validation by real-time PCR. In the longer term, DNA copy number variation (CNV) and chromosomal alterations will be investigated by high density arrays. Summary: These preliminary analyses shows that high quality gene expression data can be generated from FFPE samples, and that ethnic specific gene expression differences can be detected in tumor and matched normal breast tissue samples across ethnic groups.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2024.

Baseline serum extracellular domain HER2 expression in hormone receptor-positive metastatic breast cancer: correlation with known tissue HER2 status

Abstract #3147

Background: The extracellular domain (ECD) of the HER2 protein is cleaved by metalloproteases and shed into the serum. Serum ECD (sECD) HER2 can be detected by ELISA and may have prognostic/predictive associations in patients (pts) with breast cancer. Although use of sECD HER2 as a surrogate for HER2 overexpression in hormone receptor-positive (HR+) metastatic breast cancer (MBC) is controversial, seroconversion can occur at disease relapse and may reflect a change in tumor HER2 status that is associated with a poorer prognosis. EGF30008 is a double-blind, placebo-controlled, first-line, phase III trial of letrozole with/without lapatinib in 1,286 postmenopausal women with HR+ MBC. We report baseline sECD HER2 at study entry on all pts and the association with original tumor HER2 status.
 Methods: Serum samples were collected at study entry and every 4 weeks on study, including at disease progression. Patients were defined as sECD HER2+ if baseline sECD HER2 was ≥15 ng/mL. HER2 status was evaluated in tumor tissue by both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), using conventional cutoffs. To assess the correlation between baseline sECD HER2 and tumor tissue HER2 status, odds ratios (OR) with 95% confidence intervals (CI) and sensitivity/specificity (tumor tissue HER2 status as standard) were calculated. Data were from a blinded cutoff on 12May08. These analyses will be repeated after the database is finalized and unblinded.
 Results: Mean age was 63 ± 9.8 years. All pts had a HR+ original tumor, and 217 (17%) pts were confirmed as HER2+ by IHC or FISH. Median time from primary diagnosis to MBC was
 3.3 years (range 0 - 33.9 yrs). Baseline sECD HER2 levels ranged from 2.5 to > 560 ng/mL (mean 21 ± 60 ng/mL) with a bimodal distribution consistent with previously published data. The mean was 62 ng/mL (range 2.8 to > 560 ng/mL) for HER2+ pts and 12 ng/mL (range 2.5 to 113.1 ng/mL) for HER2-negative pts. The OR between sECD HER2 at study entry and HER2 status of the original tumor was 4.5 (95% CI: 3.2, 6.2) with 42% sensitivity and 86% specificity.
 Conclusions: This OR suggests some correlation exists between baseline sECD HER2 and original tumor HER2 status. We cannot assess the rate of seroconversion that may have occurred from primary diagnosis until MBC at study entry. The bimodal distribution suggests that a clear cohort of pts exists at the time of relapse/study entry who are positive for sECD HER2. Analyses are evaluating whether subsequent changes in sECD HER2 levels occur over time during therapy, whether seroconversion predicts for a shorter time to relapse during letrozole monotherapy, and whether any differences exist in sECD HER2 levels over time for pts treated with letrozole plus lapatinib are ongoing.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3147.

BCIRG 007: First overall survival analysis of randomized phase III trial of trastuzumab plus docetaxel with or without carboplatin as first line therapy in HER2 amplified metastatic breast cancer (MBC)

LBA1008

Background: Based on preclinical synergism between docetaxel (T), carboplatin (C) and trastuzumab (H), BCIRG conducted a phase III trial in HER2-positive MBC to evaluate efficacy and safety of H in combination with T or TC. Methods: 263 patients (pts) with HER2 FISH+ MBC were randomized to TH (H with T 100mg/m2) or TCH (H with T 75mg/m2 and C AUC=6). Chemotherapy was given every 3 weeks (q3w) for 8 cycles with weekly H at 2mg/kg (loading dose of 4 mg/kg) followed by H q3w at 6 mg/kg until progression. Pts were stratified by centre and prior (neo) adjuvant taxane chemotherapy. Primary endpoint was Time To disease Progression (TTP). Secondary endpoints include overall survival, response rate, duration of response (DR), clinical benefit (CB) and safety. Results: 131 pts were treated in each arm Pt characteristics were well balanced in both groups. A first efficacy analysis was conducted at 204 events. There was no significant difference between TH and TCH in median TTP (11.1 vs 10.4 mos, p=0.57), ORR (73% in both arms), DR (10.7 vs 9.4 mos) and CB (67% in both arms). At 39 months of median follow-up, median overall survival was 36.40 and 36.57 months in TH and TCH arms respectively. More patients on TCH received the max number of chemotherapy cycles, and numerically fewer patients on TCH discontinued treatment as a result of non hematological toxicity. The most common gr 3/4 toxicities were: Neutropenic infection that was 16.8% vs 9.2% respectively for TH and TCH, thrombocytopenia (2% vs 15%), asthenia (5% vs 12%), anemia (5% vs 11%), and diarrhea (2% vs 10%). Two pts died (1.5%) due to sepsis in TCH. Absolute LVEF decline > 15 % were seen in 5.5 % vs 6.7 % of pts. One pt (0.8%) had a symptomatic CHF in TH arm. Conclusion: Both TH (T 100) and TCH (T 75) were highly effective treatment regimens in women having HER2-positive MBC, demonstrating high response rates, median TTP > 10 months, and median overall survival > 36 months in both TH and TCH. Cardiac toxicity was no significant problem with either treatment.

[Table: see text]

A phase I pharmacokinetic study of PR-104, a hypoxia-targeting agent, in patients with solid tumors

3516

Background: PR-104 is a novel pre-prodrug (precursor of a prodrug) designed to form a cytotoxic nitrogen mustard (alkylating agent) in hypoxic regions of tumors. Following IV administration, PR-104 is converted by systemic phosphatases to the alcohol intermediate PR-104A, which, under hypoxic conditions, is reduced to form the active DNA-crosslinking mustard species PR-104H. This phase I trial defines a Maximally Tolerated Dose (MTD) and pharmacokinetics (PK) for this schedule. Methods: Patients (pts) with relapsed/recurrent solid tumors received PR-104 as a 1-hour IV infusion every 3 weeks with PK sampling on days 1–2 of cycle 1. Cohorts of ≥3 pts were treated starting at 135 mg/m2. Results: 23 pts have been enrolled: median age 51 years (range 29–72); 13 (57%) male. Most pts had received prior radiation or chemotherapy and had metastatic disease. Six dose levels (135, 216, 354, 550, 770, and 1,100 mg/m2) have been evaluated. Dose-limiting toxicity (DLT) was observed in one patient at 1,100 mg/m2 (grade 3 fatigue) and this dose level was expanded to 6 pts. In the first 4 cohorts, 54 adverse events (AEs) were considered drug-related by the investigator including nausea (26% of all AEs), fatigue (19%), vomiting (11%) and anorexia (6%); remaining AEs each constituted < 3% of the total. Of 16 grade 3 AEs, 3 were considered drug-related by the investigator (anemia, dehydration and vomiting). Prophylactic anti-emetics largely prevented nausea and vomiting at higher doses, at which dose-related decreases in neutrophils and platelets were seen. Conclusions: PR-104 has shown manageable toxicities similar to other cytotoxic agents, with no serious mucositis, diarrhea or alopecia. DLT is likely to be myelosuppression based on preclinical and current clinical data, with the MTD close to 1,100 mg/m2. The preclinical PK target for the alcohol intermediate has been exceeded at higher doses and, while no objective responses have been documented, reductions in tumor volume have been seen at these doses.

[Table: see text]

No significant financial relationships to disclose.

Insulin-like growth factor I receptor (IGF-IR) inhibition in trastuzumab (T) resistant HER2+ breast cancer (BrCa) cells

14049

Background: IGF-IR signaling interferes with the growth inhibitory action of T in BrCa cell lines and may play a role in clinical resistance to T. We studied the effect of IGF-IR inhibition on T resistance. Methods: HER2 and IGF-IR protein levels were determined by ELISA. T growth inhibition of HER2+ BrCa cell lines was measured by cell counting. HER2 and IGF-IR activity were determined by immunoprecipitation with HER2 and IGF-IR antibodies, followed by western blotting with phospho-tyrosine antibody. The effects of IGF- I/IGF-IR inhibition on proliferation and response to T were investigated. Results: No significant correlation was found between HER2, phospho-HER2 or IGF-IR levels and response to T in 12 HER+ BrCa lines. However, two T-conditioned cell lines show resistance to T (BT474 - 2.6 fold; SKBR3 - 1.8 fold) and have higher levels of phospho-IGF-IR compared to parental cell lines. Neither IGFBP3 nor IGF-IR antibody aIR3 significantly inhibited the growth of T-conditioned cell lines or enhanced the anti-proliferative effects of T. IGF-IR siRNA decreased IGF-IR protein levels and inhibited proliferation (29.8 ± 9.3 %) of T-conditioned SKBR3 cells. IGF-IR siRNA also enhanced T growth inhibition of T-conditioned SKBR3 cells (47.7 ± 13.7 % compared to 17.7 ± 14.8 % for T alone). The small molecule IGF-IR tyrosine kinase inhibitor (TKI), NVP-AEW541, inhibited growth of parental and T-conditioned SKBR3 cells and enhanced response to T (Table). Conclusions: Increased activation of IGF-IR may play a role in resistance to T. Inhibition of IGF-I ligand binding does not appear to alter IGF-IR mediated T-resistance. However, reducing IGF-IR protein levels or blocking IGF-IR TK activity improves response to T in resistant cells. Thus, the combination of IGF-IR TKIs, such as NVP-AEW541, with T may be beneficial for T-resistant HER2+ BrCa.

[Table: see text]

[Table: see text]

BCIRG 007: Randomized phase III trial of trastuzumab plus docetaxel with or without carboplatin first line in HER2 positive metastatic breast cancer (MBC)

LBA516

Background: Based on preclinical synergism between docetaxel (T), carboplatin (C) and trastuzumab (H), BCIRG conducted a phase III trial for women with HER2+ MBC to evaluate efficacy and safety of H in combination with T or TC. Methods: 263 patients (pts) with HER2 FISH+ MBC were randomized to TH, (H with T 100 mg/m2) or TCH, (H with T 75 mg/m2 and C AUC=6). Chemo was given q3 wks for 8 cycles with wkly H at 2 mg/kg (loading dose of 4 mg/kg), followed by H q3 wks at 6 mg/kg until progression. Pts were stratified by centre and prior (neo) adjuvant taxane chemotherapy. Primary endpoint was TTP with 80% power (0.05 significance) to detect a 50% improvement in median TTP between the 2 arms. Secondary endpoints include overall survival, response rate, duration of response (DR), clinical benefit (CB) and safety. Results: 131 pts were treated in each arm. Pt characteristics were well balanced in both groups. Importantly, only 52% of pts received C at the protocol specified dose (RDI > 0.9). Efficacy analysis was conducted at 204 events. There was no significant difference between TH and TCH in median TTP (11.1 vs 10.4 mos, p = 0.57), ORR (73% in both arms), DR (10.7 vs 9.4 mos) and CB (67% in both arms). The most common gr 3/4 toxicities were: infection (44% vs 30%), neutropenic infection (22% vs 12%), thrombocytopenia (2% vs 15%), febrile neutropenia (12% vs 13%) asthenia (5% vs 12%), anemia (5% vs 11%), and diarrhea (2% vs 9%). Two pts died (1.5%) due to sepsis in TCH. Absolute LVEF decline > 15% were seen in 5.5% vs 6.7% of pts. One pt (0.8%) had a symptomatic CHF in TH arm Conclusions: The already effective TH regimen does not benefit from the addition of C, when the T dose in TH is 100 mg/m2 and 75 mg/m2 in TCH, in women with HER2+ MBC.

No significant financial relationships to disclose.

Anti-VEGF antibody bevacizumab (Avastin) with 5FU/LV as third line treatment for colorectal cancer

BACKGROUND

To evaluate the activity and safety of bevacizumab when given with standard 5FU/leukovorin (LV) regimens in patients with metastatic colorectal cancer who have failed irinotecan and oxaliplatin-based treatments.

METHODS

Bevacizumab was given at 5 mg/kg as an IV infusion every 2 weeks. Patients received 5FU according to Roswell Park or the de Gramont regimen.

RESULTS

Nineteen patients enrolled, median age 60, median PS: 1. Most common toxicity attributable to bevacizumab was mild hypertension, epistaxis and mild proteinuria; 1 patient had a CNS haemorrhage. The median number of cycles was 1 (8 weeks). Clinical benefit as disease stabilisation lasting 2-6 months was noted in 9 patients, whereas 10 progressed (median f/u: 5 months). TTP was 16 weeks, and the overall survival has not been reached (24+ weeks).

CONCLUSIONS

Bevacizumab may result in growth arrest and clinical benefit in a substantial proportion of patients with colorectal cancer and no alternative treatment.

HER-2/neu overexpression and in vitro chemosensitivity to CMF and FEC in primary breast cancer

Available clinical and experimental data on the effect of HER-2/neu overexpression on chemosensitivity are controversial. It was the purpose of this in vitro study to define the association between HER-2/neu overexpression and the sensitivity to the chemotherapeutic drug combinations of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) and 5-fluorouracil, epirubicin and cyclophosphamide (FEC) of breast cancer cells derived from 140 chemotherapy-naïve patients at the time of primary surgery. Both drug combinations were tested at six different concentrations ranging from 6.25-200% peak plasma concentration (PPC). Immunohistochemical detection of HER-2/neu overexpression was performed with the HER-2/neu antibodies, CB11, TAB250 and AO485, in the same tumor specimens. Immunoreactions were determined as negative (0/1+), weakly positive (2+) and strongly positive (3+). However, the antibodies varied in their degrees of sensitivity. Breast cancer samples with strong (3+) HER-2/neu overexpression demonstrated 90% growth inhibition (IC90) at significantly lower PPC values, using the CB11 (p = 0.048), TAB250 (p = 0.007) and AO485 (p < or =0.01) antibodies, and showed 50% growth inhibition (IC50) at significantly lower PPC values, using the CB11 antibody (p = 0.01) compared to their counterparts with lower levels of HER-2/neu expression. When analyzing the group of patients with intermediate and strong HER-2/neu overexpression (2+ and 3+), an association between HER-2/neu overexpression and increased chemosensitivity was seen with the TAB250 (p = 0.044) and AO485 (p = 0.032) antibodies, but not with the CB11 antibody (p =0.8) at the IC90 level. Differences in chemosensitivity between samples with strong HER-2/neu overexpression and those with lower levels were then analyzed separately for CMF and FEC. Both regimens achieved 90% tumor growth inhibition at lower PPC values in samples with strong HER-2/neu overexpression (3+) compared to their counterparts with lower expression levels (AO485 p = 0.011 for CMF, and p = 0.09 for FEC). Cumulative concentration-response plots of tumors responding in vitro with 90% tumor cell inhibition showed a stronger dose dependence for both CMF and FEC among tumor samples with strong HER-2/neu overexpression compared to those with lower levels of expression. In conclusion, the data show that HER-2/neu overexpression was not associated with in vitro drug resistance to CMF or FEC. In contrast, tumors with strong HER-2/neu overexpression demonstrated increased dose-dependent in vitro sensitivity to both the FEC and CMF regimens.

Her-2/neu and urokinase-type plasminogen activator and its inhibitor in breast cancer

PURPOSE

Recent studies suggest that HER-2/neu specifically promotes the invasive capacity of tumor cells by up-regulating secretion of the proteolytic enzyme, urokinase-type plasminogen activator (uPA), or its inhibitor, plasminogen activator inhibitor-1 (PAI-1), in colon and gastric cancer. It was the purpose of this study to: (a) evaluate the association between HER-2/neu and uPA and PAI-1 expression in a large primary breast cancer cohort; (b) perform the first multivariate analysis, including HER-2/neu, uPA, and PAI-1 in breast cancer; and (c) define the effect of HER-2/neu overexpression on uPA and PAI-1 expression in breast cancer cells.

EXPERIMENTAL DESIGN

HER-2/neu, uPA, and PAI-1 were measured as continuous variables by ELISA in primary breast cancer tissue extracts from 587 patients with clinical follow-up and analyzed for correlations with clinical outcome. Furthermore, a full-length human HER-2/neu cDNA was introduced into five human breast cancer cell lines to define the effects of HER-2/neu overexpression on uPA and PAI-1 expression. In addition, we tested whether HER-2/neu antibodies could reverse any given alteration of uPA and PAI-1 levels.

RESULTS

Our findings indicate a weak positive association between HER-2/neu and uPA (r = 0.147; P < 0.001) and no association between HER-2/neu and PAI-1 (r = 0.07; P = 0.085). HER-2/neu overexpression (> or =400 fmol/mg) and high levels of uPA/PAI-1 (> or =5.5 ng/mg and/or > or =14 ng/mg, respectively) were significantly associated with shorter disease-free survival (DFS; P < 0.001 and P = 0.003) and metastasis-free survival (MFS; P = 0.015 and P < 0.001). Multivariate analysis revealed prognostic independence between HER-2/neu and the uPA/PAI-1 axis for DFS and MFS. Both uPA and PAI-1 had no significant discriminatory effect among HER-2/neu-positive patients for DFS. The prognostic value of HER-2/neu overexpression for MFS, however, was significantly enhanced by elevated uPA expression (P = 0.053). Stable transfection of the HER-2/neu gene into multiple human breast cancer cell lines resulted in consistent down-regulation of uPA or PAI-1 expression. In addition, anti-HER-2/neu antibodies did not significantly affect uPA or PAI-1 expression in human cancer cell lines naturally overexpressing HER-2/neu.

CONCLUSIONS

The present findings suggest that the invasive phenotype elicited by HER-2/neu overexpression in breast cancer is not a direct effect of uPA or PAI-1 expression. HER-2/neu and the uPA/PAI-1 axis have been shown to affect the invasive capacity of breast cancer independently. Determination of uPA can provide significant additional prognostic information for MFS in HER-2/neu-positive and -negative patients.

Association of urokinase-type plasminogen activator and its inhibitor with disease progression and prognosis in ovarian cancer

PURPOSE

Urokinase-type plasminogen activator (uPA) and its inhibitor, plasminogen activator inhibitor (PAI)-1, have been shown to be related to poor prognosis in a variety of malignant solid tumors. Studies on the prognostic relevance of uPA and PAI-1 in ovarian cancer, however, have been inconclusive. The current study tests the hypothesis that elevated expression of uPA and PAI-1 is associated with prognosis and disease progression.

EXPERIMENTAL DESIGN

uPA and PAI-1 were prospectively measured by quantitative ELISA in tumor samples from 103 ovarian cancer patients (82 primary invasive epithelial carcinomas, 9 low malignant potential tumors, and 12 recurrent ovarian carcinomas).

RESULTS

uPA but not PAI-1 levels were consistently associated with malignant progression, with levels increased from low malignant potential tumors to primary tumors (uPA, P = 0.04; PAI-1, P = 0.019), from early to advanced disease stages (uPA, P = 0.014; PAI-1, P = 0.23), and from primary to intra-abdominal metastatic tumors (uPA, P = 0.001; PAI-1, P = 0.16). High uPA and PAI-1 levels were associated with residual tumor volumes of >1 cm (P = 0.001 and P = 0.016, respectively). Among invasive International Federation of Gynecologists and Obstetrician stages I-IV tumors, elevated levels of uPA (>5.5 ng/mg) and PAI-I (>18.8 ng/ml) were associated with a shortened progression-free survival (uPA, P = 0.003; PAI-1, P = 0.039) and overall survival (uPA, P = 0.0002; PAI-1, P = 0.007). In multivariate analysis, uPA retained prognostic independence for progression-free survival (P = 0.037) and overall survival (P = 0.006).

CONCLUSIONS

These data suggest that the uPA/PAI-1 axis may play an important role in the intra-abdominal spread and reimplantation of ovarian cancer cells. The prognostic relevance of uPA and PAI-1 supports their possible role in the malignant progression of ovarian cancer.