International expert consensus on primary systemic therapy in the management of early breast cancer: highlights of the Fourth Symposium on Primary Systemic Therapy in the Management of Operable Breast Cancer, Cremona, Italy (2010)

A panel of international breast cancer experts formulated a declaration of consensus regarding many key issues in the use of primary systemic therapy (PST) either in clinical routine or research practice. The attainment of pathological complete response (pCR), defined as no residual invasive tumor in the surgical specimens both in breast and in axillary nodes, is one of the main goals of PST, and pCR can be used as the primary objective in prospective clinical trials. However, pCR is not a reliable endpoint with all treatment approaches, and alternatives such as Ki67 index of the residual invasive disease or after 2 weeks of PST are also potential endpoints. PST has several advantages: breast conservation and the unique opportunity to obtain information on the interaction between treatment and tumor biology. Changes in tumor biology after PST are an early phenomenon; so, an additional core biopsy performed after 14 days from treatment start should be considered in clinical trials.

VEGF-D promotes tumor metastasis by regulating prostaglandins produced by the collecting lymphatic endothelium

Lymphatic metastasis is facilitated by lymphangiogenic growth factors VEGF-C and VEGF-D that are secreted by some primary tumors. We identified regulation of PGDH, the key enzyme in prostaglandin catabolism, in endothelial cells of collecting lymphatics, as a key molecular change during VEGF-D-driven tumor spread. The VEGF-D-dependent regulation of the prostaglandin pathway was supported by the finding that collecting lymphatic vessel dilation and subsequent metastasis were affected by nonsteroidal anti-inflammatory drugs (NSAIDs), known inhibitors of prostaglandin synthesis. Our data suggest a control point for cancer metastasis within the collecting lymphatic endothelium, which links VEGF-D/VEGFR-2/VEGFR-3 and the prostaglandin pathways. Collecting lymphatics therefore play an active and important role in metastasis and may provide a therapeutic target to restrict tumor spread.

MET amplification identifies a small and aggressive subgroup of esophagogastric adenocarcinoma with evidence of responsiveness to crizotinib

PURPOSE

Amplification of the MET proto-oncogene in gastroesophageal cancer (GEC) may constitute a molecular marker for targeted therapy. We examined a GEC cohort with follow-up and reported the clinical response of four additional patients with MET-amplified tumors to the small molecule inhibitor crizotinib as part of an expanded phase I cohort study.

PATIENTS AND METHODS

From 2007 to 2009, patients with GEC were genetically screened as a consecutive series of 489 tumors (stages 0, I, and II, 39%; III, 25%; IV, 36%; n = 222 esophageal, including n = 21 squamous carcinomas). MET, EGFR, and HER2 amplification status was assessed by using fluorescence in situ hybridization.

RESULTS

Ten (2%) of 489 patients screened harbored MET amplification; 23 (4.7%) harbored EGFR amplification; 45 (8.9%) harbored HER2 amplification; and 411 (84%) were wild type for all three genes (ie, negative). MET-amplified tumors were typically high-grade adenocarcinomas that presented at advanced stages (5%; n = 4 of 80). EGFR-amplified tumors showed the highest fraction of squamous cell carcinoma (17%; n = 4 of 23). HER2, MET, and EGFR amplification were, with one exception (MET and EGFR positive), mutually exclusive events. Survival analysis in patients with stages III and IV disease showed substantially shorter median survival in MET/EGFR-amplified groups, with a rank order for all groups by median survival (from most to least aggressive): MET (7.1 months; P < .001) less than EGFR (11.2 months; P = .16) less than HER2 (16.9 months; P = .89) when compared with the negative group (16.2 months). Two of four patients with MET-amplified tumors treated with crizotinib experienced tumor shrinkage (-30% and -16%) and experienced progression after 3.7 and 3.5 months.

CONCLUSION

MET amplification defines a small and aggressive subset of GEC with indications of transient sensitivity to the targeted MET inhibitor crizotinib (PF-02341066).

PD08-02: Targeting BCL-2 Expressing Breast Tumors with BH3-Mimetics – A New Class of Drugs in Breast Cancer?

Background: Impairment of apoptosis is a hallmark of cancer and can result in resistance to chemotherapy. Tumor resistance to apoptosis is frequently acquired through deregulated expression of BCL-2 family members or inactivation of the p53 tumor suppressor pathway. Over-expression of the pro-survival protein BCL-2 is common in breast cancer (where it is readily detected by immunostaining), and has been shown to be an important prognostic marker. A potential role for BCL-2 as a therapeutic target in breast cancer, however, has not been explored. Recently, small molecules termed ‘BH3-mimetics’ have been developed that mimic the action of pro-apoptotic BH3-only proteins. These bind and neutralize pro-survival proteins including BCL-2. Here we have derived a panel of primary breast tumor xenografts (that include basal-like breast tumors) to study the efficacy of the BH3-mimetic ABT-737 combined with docetaxel in targeting BCL-2-positive breast cancer.

Methods and Results: We first studied the expression of BCL-2, pro-survival family members BCL-XL and MCL-1, and the pro-apoptotic protein BIM in tissue microarrays of 197 primary breast tumors, which were subtyped on the basis of ER, PR, HER2, CK5/6 and EGFR expression. BCL-2 was overexpressed in luminal (83.3%), HER2−positive (50.0%), basal-like (18.5%) and ‘marker-null’ (41.4%) breast cancers. BCL-2-positive tumors generally co-expressed BCL-XL (96.2%), MCL-1 (94.7%) and BIM (93.5%). To determine whether the BH3-mimetic ABT-737 (which neutralizes BCL-2, BCL-XL and BCL-W) was effective in targeting BCL-2-expressing breast tumors, we generated a panel of 28 primary breast tumor xenografts in immunocompromised NOG mice. Five xenograft lines (838T, 24T, 315T, 13T and 806T) were selected for further analysis. Four were basal-like, and one (315T) was a luminal B tumor, as determined by gene profiling. Mice bearing tumor xenografts were treated with ABT-737 (50 mg/kg i.p. d1-10), docetaxel (10 mg/kg i.p. d1) or a combination in q21d cycles. Tumor response and overall survival were significantly improved by combination therapy, but only for tumors that expressed elevated levels of BCL-2. Treatment with ABT-737 alone was ineffective, suggesting that ABT-737 sensitized tumors to docetaxel. Combination therapy was accompanied by a marked increase in apoptosis and dissociation of BIM from BCL-2, indicating that a perturbation of BIM complexes may contribute to the activation of the apoptotic cascade. Notably, ABT-737 appeared effective in targeting BCL-2-expressing basal-like tumor xenografts (838T and 24T) harboring p53 mutations.

Discussion: Primary breast tumor xenograft models that recapitulate the phenotype of the primary tumor have been developed as useful ‘proof-of-principle', pre-clinical models. Here we provide the first in vivo evidence that BH3-mimetics can be used to sensitize primary BCL-2-expressing breast tumors to taxane chemotherapy. Our results suggest that elevated BCL-2 expression constitutes a predictive response marker in breast cancer. These findings provide a rationale for the development of clinical protocols using the oral analogue ABT-263 (navitoclax) as an adjunct to taxane chemotherapy in BCL-2-expressing basal-like and luminal breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD08-02.

A high-throughput protocol for mutation scanning of the BRCA1 and BRCA2 genes

BACKGROUND

Detection of mutations by DNA sequencing can be facilitated by scanning methods to identify amplicons which may have mutations. Current scanning methods used for the detection of germline sequence variants are laborious as they require post-PCR manipulation. High resolution melting (HRM) is a cost-effective rapid screening strategy, which readily detects heterozygous variants by melting curve analysis of PCR products. It is well suited to screening genes such as BRCA1 and BRCA2 as germline pathogenic mutations in these genes are always heterozygous.

METHODS

Assays for the analysis of all coding regions and intron-exon boundaries of BRCA1 and BRCA2 were designed, and optimised. A final set of 94 assays which ran under identical amplification conditions were chosen for BRCA1 (36) and BRCA2 (58). Significant attention was placed on primer design to enable reproducible detection of mutations within the amplicon while minimising unnecessary detection of polymorphisms. Deoxyinosine residues were incorporated into primers that overlay intronic polymorphisms. Multiple 384 well plates were used to facilitate high throughput.

RESULTS

169 BRCA1 and 239 BRCA2 known sequence variants were used to test the amplicons. We also performed an extensive blinded validation of the protocol with 384 separate patient DNAs. All heterozygous variants were detected with the optimised assays.

CONCLUSIONS

This is the first HRM approach to screen the entire coding region of the BRCA1 and BRCA2 genes using one set of reaction conditions in a multi plate 384 well format using specifically designed primers. The parallel screening of a relatively large number of samples enables better detection of sequence variants. HRM has the advantages of decreasing the necessary sequencing by more than 90%. This markedly reduced cost of sequencing will result in BRCA1 and BRCA2 mutation testing becoming accessible to individuals who currently do not undergo mutation testing because of the significant costs involved.

Recruitment of regulatory T cells is correlated with hypoxia-induced CXCR4 expression, and is associated with poor prognosis in basal-like breast cancers

Introduction

Basal-like breast cancers behave more aggressively despite the presence of a dense lymphoid infiltrate. We hypothesised that immune suppression in this subtype may be due to T regulatory cells (Treg) recruitment driven by hypoxia-induced up-regulation of CXCR4 in Treg.

Methods

Immunoperoxidase staining for FOXP3 and CXCL12 was performed on tissue microarrays from 491 breast cancers. The hypoxia-associated marker carbonic anhydrase IX (CA9) and double FOXP3/CXCR4 staining were performed on sections from a subset of these cancers including 10 basal-like and 11 luminal cancers matched for tumour grade.

Results

High Treg infiltration correlated with tumour CXCL12 positivity (OR 1.89, 95% CI 1.22 to 2.94, P = 0.004) and basal phenotype (OR 3.14, 95% CI 1.08 to 9.17, P = 0.004) in univariate and multivariate analyses. CXCL12 positivity correlated with improved survival (P = 0.005), whereas high Treg correlated with shorter survival for all breast cancers (P = 0.001), luminal cancers (P < 0.001) and basal-like cancers (P = 0.040) that were confirmed in a multivariate analysis (OR 1.61, 95% CI 1.02 to 2.53, P = 0.042). In patients treated with hormone therapy, high Treg were associated with a shorter survival in a multivariate analysis (OR 1.78, 95% CI 1.01 to 3.15, P = 0.040). There was a tendency for luminal cancers to show CXCL12 expression (102/138, 74%) compared to basal-like cancers (16/27, 59%), which verged on statistical significance (P = 0.050). Up-regulation of CXCR4 in Treg correlated with the basal-like phenotype (P = 0.029) and tumour hypoxia, as indicated by CA9 expression (P = 0.049).

Conclusions

Our data show that in the setting of hypoxia and CXCR4 up-regulation in Treg, CXCL12 expression may have the negative consequence of enhancing Treg recruitment and suppressing the anti-tumour immune response.

Abstract 113: Aberrant DNA methylation of the HIF-1α inhibitor gene CITED4 in breast cancer

CBP/p300-interacting transactivator with ED-rich carboxy-terminal domain, 4 (CITED4) inhibits the interaction between HIF-1α and p300/CBP thereby reducing expression of downstream hypoxia responsive genes. Since we have previously shown that diminished levels of nuclear CITED4 as a consequence of down-regulation or translocation to the cytoplasm are correlated with HIF-1α elevation in breast cancer, we hypothesized that either hypermethylation or somatic mutation of the CITED4 gene may also underlie elevated HIF-1α levels in breast tumors.

CITED4 DNA methylation and mutation were analyzed in 168 breast carcinoma samples and 23 cancer cell lines using methylation-sensitive high resolution melting (MS-HRM) and DNA sequencing, respectively. Although no somatic CITED4 mutation was found, there was evidence of CITED4 promoter region methylation in five breast carcinoma samples, and three breast cancer cell lines (heterogeneously methylated in Hs578T and MDA-MB-231, and fully methylated in MDA-MB-453). There was a significant association between low CITED4 mRNA and high methylation in Hs578T (P = 0.0001) and MDA-MB-231 (P &lt; 0.0001) and no expression was found in fully methylated cell line MDA-MB-453.

Methylated CITED4 breast cancer cell lines were treated with 5-aza-2-deoxycytidine (DAC) and/or trichostatin A to evaluate the regulation of CITED4 expression through DNA methylation. CITED4 expression was re-expressed in fully methylated MDA-MB-453 cell line and increased expression in MDA-MB-231 (21.9-fold) and Hs578T (4.9-fold) after DAC mediated demethylation, and treatment with trichostatin A alone also resulted in increased CITED4 expression. A synergistic effect was seen after the combined treatment of DAC and trichostatin A.

Furthermore, re-expressed CITED4 expression after DAC treatment may reduce HIF-1α and its downstream genes activity. MDA-MB-231 breast cancer cell line treated with DAC under hypoxia (0.1% oxygen) and demonstrated the downregulation of HIF-1α downstream genes VEGFA and SLC2A1 (P = 0.0029) when compared with the untreated MDA-MB-231 cell line under hypoxia. Immunohistochemstry also demonstrated that HIF-1α and downstream CA9 levels had decreased after CITED4 re-expressed under the hypoxic condition from 23% of positive staining in control to 10% after DAC treatment for HIF-1α and from 5 % to 3% for CA9.

These data suggest that, CITED4 gene expression can be epigenetically silenced through DNA methylation in breast cancer, which may enhance the activity of HIF in developing aggressive breast cancer phenotypes.

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 113. doi:10.1158/1538-7445.AM2011-113

The expression of the ubiquitin ligase SIAH2 (seven in absentia homolog 2) is mediated through gene copy number in breast cancer and is associated with a basal-like phenotype and p53 expression

Introduction

The seven in absentia homolog 2 (SIAH2) protein plays a significant role in the hypoxic response by regulating the abundance of hypoxia-inducible factor-α; however, its role in breast carcinoma is unclear. We investigated the frequency and expression pattern of SIAH2 in two independent cohorts of sporadic breast cancers.

Methods

Immunohistochemical evaluation of SIAH2protein expression was conducted in normal breast tissues and in tissue microarrays comprising ductal carcinoma in situ (DCIS) and a cohort of invasive breast carcinomas. Correlation analysis was performed between SIAH2 and clinicopathological variables and intrinsic breast cancer subgroups and validated in a cohort of 293 invasive ductal carcinomas. Promoter methylation, gene copy number and mRNA expression of SIAH2 were determined in a panel of basal-like tumors and cell lines.

Results

There was a significant increase in nuclear SIAH2 expression from normal breast tissues through to DCIS and progression to invasive cancers. A significant inverse correlation was apparent between SIAH2 and estrogen receptor and progesterone receptor and a positive association with tumor grade, HER2, p53 and an intrinsic basal-like subtype. Logistic regression analysis confirmed the significant positive association between SIAH2 expression and the basal-like phenotype. No SIAH2 promoter methylation was identified, yet there was a significant correlation between SIAH2 mRNA and gene copy number. SIAH2-positive tumors were associated with a shorter relapse-free survival in univariate but not multivariate analysis.

Conclusions

SIAH2 expression is upregulated in basal-like breast cancers via copy number changes and/or transcriptional activation by p53 and is likely to be partly responsible for the enhanced hypoxic drive through abrogation of the prolyl hydroxylases.

The prolyl hydroxylase enzymes are positively associated with hypoxia-inducible factor-1α and vascular endothelial growth factor in human breast cancer and alter in response to primary systemic treatment with epirubicin and tamoxifen

Introduction

The purpose of the present study was to investigate the relationship of expression of hypoxia inducible factor (HIF)-1α-modifying enzymes prolyl hydroxylase (PHD)1, PHD2 and PHD3 to response of tumours and survival in breast cancer patients enrolled in a phase II trial of neoadjuvant anthracycline and tamoxifen therapy.

Methods

The expression of PHD1, PHD2 and PHD3 together with HIF-1α and the HIF-inducible genes vascular endothelial cell growth factor (VEGF) and carbonic anhydrase IX were assessed by immunohistochemistry using a tissue microarray approach in 211 patients with T2-4 N0-1 breast cancer enrolled in a randomised trial comparing single-agent epirubicin versus epirubicin and tamoxifen as the primary systemic treatment.

Results

PHD1, PHD2 and PHD3 were detected in 47/179 (26.7%), 85/163 (52.2%) and 69/177 (39%) of tumours at baseline. PHD2 and PHD3 expression was moderate/strong whereas PHD1 expression was generally weak. There was a significant positive correlation between HIF-1α and PHD1 (P = 0.002) and PHD3 (P < 0.05) but not PHD2 (P = 0.41). There was a significant positive relationship between VEGF and PHD1 (P < 0.008) and PHD3 (P = 0.001) but not PHD2 (P = 0.09). PHD1, PHD2 and PHD3 expression was significantly increased after epirubicin therapy (all P < 0.000) with no significant difference in PHD changes between the treatment arms. There was no significant difference in response in tumours that expressed PHDs and PHD expression was not associated with survival.

Conclusions

Although expression of the PHDs was not related to response or survival in patients receiving neoadjuvant epirubicin, our data provide the first evidence that these enzymes are upregulated on therapy in breast cancer and that the biological effects independent of HIF make them therapeutic targets.

Enhanced RAD21 cohesin expression confers poor prognosis and resistance to chemotherapy in high grade luminal, basal and HER2 breast cancers

INTRODUCTION

RAD21 is a component of the cohesin complex, which is essential for chromosome segregation and error-free DNA repair. We assessed its prognostic and predictive power in a cohort of in situ and invasive breast cancers, and its effect on chemosensitivity in vitro.

METHODS

RAD21 immunohistochemistry was performed on 345 invasive and 60 pure in situ carcinomas. Integrated genomic and transcriptomic analyses were performed on a further 48 grade 3 invasive cancers. Chemosensitivity was assessed in breast cancer cell lines with an engineered spectrum of RAD21 expression.

RESULTS

RAD21 expression correlated with early relapse in all patients (hazard ratio (HR) 1.74, 95% confidence interval (CI) 1.06 to 2.86, P = 0.029). This was due to the effect of grade 3 tumors (but not grade 1 or 2) in which RAD21 expression correlated with early relapse in luminal (P = 0.040), basal (P = 0.018) and HER2 (P = 0.039) groups. In patients treated with chemotherapy, RAD21 expression was associated with shorter overall survival (P = 0.020). RAD21 mRNA expression correlated with DNA copy number, with amplification present in 32% (7/22) of luminal, 31% (4/13) of basal and 22% (2/9) of HER2 grade 3 cancers. Variations in RAD21 mRNA expression in the clinical samples were reflected in the gene expression data from 36 breast cancer cell lines. Knockdown of RAD21 in the MDA-MB-231 breast cancer cell line significantly enhanced sensitivity to cyclophosphamide, 5-fluorouracil and etoposide. The findings for the former two drugs recapitulated the clinical findings.

CONCLUSIONS

RAD21 expression confers poor prognosis and resistance to chemotherapy in high grade luminal, basal and HER2 breast cancers. RAD21 may be a novel therapeutic target.

Leukocyte adhesion-GPCR EMR2 is aberrantly expressed in human breast carcinomas and is associated with patient survival

EGF-like module containing mucin-like hormone receptor 2 (EMR2) is a leukocyte-restricted adhesion G protein-coupled receptor. Aberrant expression of EMR2 and its highly homologous molecule CD97 have been reported in various human cancers. Herein, we investigate the expression of EMR2 in neoplastic breast human tissue and its relationship with patient survival. EMR2 expression in normal and neoplastic breast tissue was assessed by immunohistochemistry in sections from 10 normal controls and micro-arrayed tissue cores from 69 cases of ductal carcinoma in situ (DCIS) and 272 invasive carcinomas. The pattern and intensity of staining was correlated with the clinicopathological characteristics of each case and the disease outcome. While absent in normal breast epithelium, EMR2 was significantly up-regulated in the cytoplasmic and nuclear compartments of both DCIS and invasive carcinoma, with invasive samples displaying significantly higher expression levels compared with in situ disease. In invasive disease, EMR2 cytoplasmic expression was significantly associated with higher tumour grade but not with patient age, nodal status, tumour size, estrogen receptor expression, relapse-free or overall survival. In contrast, EMR2 nuclear expression correlated negatively with higher tumour grade. Of note, EMR2 nuclear expression was associated with longer relapse-free survival as well as overall survival. This study indicates that EMR2 is expressed in neoplastic breast epithelium and suggests that expression patterns of EMR2 are relevant in breast cancer progression. The association of improved patient survival with higher nuclear expression levels identifies EMR2 as a potential biomarker in patients with invasive breast cancer.

Constitutional methylation of the BRCA1 promoter is specifically associated with BRCA1 mutation-associated pathology in early-onset breast cancer

Women carrying germline mutations in BRCA1 are at a substantially elevated risk of breast cancer and their tumors typically have distinctive morphologic features. We hypothesized that constitutional methylation of the BRCA1 promoter region could give rise to such breast cancers in women. We selected 255 women diagnosed with breast cancer before the age of 40 years for whom BRCA1 germline mutations had not been identified. Of them, 52 had five or more of nine BRCA1 mutation-associated morphologic features (group 1), 39 had four (group 2), and 164 had three or less (group 3). The prevalence of detectable BRCA1 promoter methylation in peripheral blood DNA decreased from 31% to 10% to 5% across groups 1-3, respectively (P = 0.000002), and was significantly greater than the 4% frequency in unaffected controls (P = 0.004). Peripheral blood methylation was associated with a 3.5-fold (95% CI, 1.4-10.5) increased risk of having early onset breast cancer. Methylation was consistently mosaic in the peripheral blood where the estimated allelic frequency of BRCA1 promoter methylation ranged from 0.1% to 17%. Group 1 women, but not group 3 women, with detectable methylation of peripheral blood DNA had high levels of BRCA1 promoter methylation of their tumor DNA, indicating that constitutional BRCA1 methylation strongly predisposes toward the development of BRCA1 methylated tumors that then have features resembling BRCA1 mutated tumors. Screening peripheral blood for BRCA1 promoter methylation might thus predict early-onset breast cancers. This raises the possibility of chemoprevention or other intervention to diminish the risk of developing breast cancer in these women.

DNA methylation analysis of the HIF-1α prolyl hydroxylase domain genes PHD1, PHD2, PHD3 and the factor inhibiting HIF gene FIH in invasive breast carcinomas

AIMS

Hypoxia-inducible factor-1 (HIF-1) activity is regulated by prolyl hydroxylase (PHD1, PHD2, PHD3) and factor inhibiting HIF-1 (FIH) that target the α subunit of HIF-1 (HIF-1α) for proteosomal degradation. We hypothesised that the elevated HIF-1α level is due in some tumours to epigenetic silencing by DNA hypermethylation of the promoter region of one or more of the PHDs and FIH genes. The aims were to define the presence or absence of promoter methylation of PHDs and FIH in cell lines of various sources and breast carcinomas and, if present, determine its effect on mRNA and protein expression.

METHODS AND RESULTS

Tumour cell lines (n = 20) and primary invasive breast carcinomas (n = 168) were examined for promoter region DNA methylation using methylation-sensitive high-resolution melting. There was evidence of PHD3 but not of PHD1, PHD2 or FIH DNA methylation in breast cancer (SkBr3) and leukaemic (HL60 and CCRF-CEM) cell lines, but there was no evidence of methylation in any of 168 breast cancers. Only the high-level PHD3 methylation seen in leukaemic cell lines correlated with absent mRNA and protein expression.

CONCLUSIONS

Methylation-induced epigenetic silencing of PHD1, PHD2, PHD3 and FIH is unlikely to underlie up-regulated HIF-1α expression in human breast cancer but may play a role in other tumour types.

Prognostic significance of p16INK4A and human papillomavirus in patients with oropharyngeal cancer treated on TROG 02.02 phase III trial

PURPOSE

To determine the prognostic importance of p16 and human papillomavirus (HPV) in patients with oropharyngeal cancer treated on a phase III concurrent chemoradiotherapy trial.

PATIENTS AND METHODS

Patients with stage III or IV head and neck squamous cell cancer were randomly assigned to concurrent radiotherapy and cisplatin with or without tirapazamine. In this substudy, analyses were restricted to patients with oropharyngeal cancer. p16 was detected by immunohistochemistry, and HPV was detected by in situ hybridization and polymerase chain reaction.

RESULTS

Slides were available for p16 assay in 206 of 465 patients, of which 185 were eligible, and p16 and HPV were evaluable in 172 patients. One hundred six (57%) of 185 were p16-positive, and in patients evaluable for both p16 and HPV, 88 (86%) of 102 p16-positive patients were also HPV-positive. Patients who were p16-positive had lower T and higher N categories and better Eastern Cooperative Oncology Group (ECOG) performance status. p16-positive tumors compared with p16-negative tumors were associated with better 2-year overall survival (91% v 74%; hazard ratio [HR], 0.36; 95% CI, 0.17 to 0.74; P = .004) and failure-free survival (87% v 72%; HR, 0.39; 95% CI, 0.20 to 0.74; P = .003). p16 was a significant prognostic factor on multivariable analysis (HR, 0.45; 95% CI, 0.21 to 0.96; P = .04). p16-positive patients had lower rates of locoregional failure and deaths due to other causes. There was a trend favoring the tirapazamine arm for improved locoregional control in p16-negative patients (HR, 0.33; 95% CI, 0.09 to 1.24; P = .13).

CONCLUSION

HPV-associated oropharyngeal cancer is a distinct entity with a favorable prognosis compared with HPV-negative oropharyngeal cancer when treated with cisplatin-based chemoradiotherapy.

DNA methylation profiling of phyllodes and fibroadenoma tumours of the breast

Phyllodes tumours and cellular fibroadenomas are both fibroepithelial tumours of the breast. Phyllodes tumours, unlike fibroadenomas, have the ability to recur and metastasise. Although these lesions can be distinguished by their stromal cellularity, mitotic index, presence or absence of stromal overgrowth and cellular atypia, there is overlap and not infrequently a definitive diagnosis cannot be made, particularly on biopsy. We sought to evaluate whether DNA promoter methylation profiling using selected genes known to be methylated in cancer would allow us to learn more about the biology of these tumours, and whether it could identify methylation markers that could differentiate phyllodes tumours from fibroadenomas and/or distinguish phyllodes tumours of different grades. Methylation-sensitive high resolution melting (MS-HRM) was used to screen promoter DNA methylation changes in 86 phyllodes tumours (15 benign, 28 borderline, 43 malignant) and 26 fibroadenomas. A panel of 11 genes (RASSF1A, TWIST1, APC, WIF1, MGMT, MAL, RARβ, CDKN2A, CDH1, TP73 and MLH1) was tested. Methylation status was correlated with histology and with clinicopathological parameters. Five of the gene promoters showed some methylation in a proportion of phyllodes tumours; RASSF1A, 45.3%; TWIST1, 10.7%; APC, 4.1%; WIF1, 2.9% and MGMT, 1.3%. Only two genes showed any methylation in fibroadenomas usually at background levels; RASSF1A, 53.8% and MGMT, 8.3%. No CDKN2A methylation was observed in either tumour type, contrary to previous reports. Overall, the methylation patterns differed little from that which might be seen in normal cells. However, significant levels of methylation of RASSF1A (24.4%) and TWIST1 (7.1%) was observed in some phyllodes tumours. Elevated RASSF1A and/or TWIST1 methylation was significantly associated with phyllodes tumours compared with fibroadenomas (P = 0.02), TWIST1 methylation correlated with increasing malignancy in phyllodes tumours (P < 0.001). In conclusion, assessment of methylation of RASSF1A and TWIST1 may aid in the diagnosis of phyllodes tumours. The absence of frequent methylation in fibroadenomas supports a non-neoplastic origin.

Nuclear and cytoplasmic expressions of ERβ1 and ERβ2 are predictive of response to therapy and alters prognosis in familial breast cancers

Estrogen receptor (ER) α has been studied extensively in familial breast cancers but there are limited data on ERβ and its isoforms. This is an important issue since many BRCA1-associated tumours are "triple negative" and are resistant to conventional and targeted therapies. We performed an immunohistochemical study of pan-ERβ, ERβ1 and ERβ2 in a cohort of 123 familial breast carcinomas (35 BRCA1, 33 BRCA2 and 55 BRCAX) using a cut-off for positivity at 20% (Shaaban et al. in Clin Cancer Res 14:5228-5235, 2008). BRCA1 cancers were more likely to be nuclear ERα negative and nuclear pan-ERβ positive (21/32, 66%) when compared with BRCA2 (2/29, 7%) and BRCAX cancers (11/49, 22%) (both P < 0.001). For survival analysis, expression was also stratified using cut-offs defined by Bates et al. (Breast Cancer Res Treat 111:453-459, 2008) (score out of 7). Cytoplasmic ERβ2 expression correlated with shorter overall survival at 15 years regardless of cut-off used (both P < 0.046) At a cut-off score of 6 out of 7, cytoplasmic ERβ2 expression correlated with a poorer response to chemotherapy in both univariate (P = 0.011) and multivariate analyses including grade, lymph node status and chemotherapy as an interaction variable (P = 0.045, Hazard ratio 1.22, 95% CI 1.004-9.87). A similar trend was seen in a univariate analysis with a cut-off of 20% although this did not reach statistical significance (P = 0.057). Expression of nuclear ERβ1 was associated with a favourable response to endocrine therapy at 15 years regardless of cut-offs employed (both P < 0.025). However, this did not reach statistical significance in a multivariate analysis (P > 0.05). Since a significant proportion of ERα negative familial breast carcinomas are positive for nuclear ERβ1 and cytoplasmic ERβ2, the different ERβ isoforms and their intracellular location may need to be assessed, to identify patients that may benefit from hormonal and chemotherapy.

Abstract 1660: The antitumor action of ASA404 (vadimezan; DMXAA); potential involvement of vascular endothelial growth factor (VEGF)

ASA404, a Tumor-Vascular Disrupting Agent developed at the Auckland Cancer Society Research Centre, is currently undergoing two Phase III clinical trials (Novartis) against non-small cell lung cancer. Its early effects on tumor tissue include increased tumor vascular permeability, increased tumor endothelial apoptosis, decreased tumor blood flow and increased tumor hypoxia. The basis for the selective effect of ASA404 on tumor versus normal vasculature is not clear. We hypothesized that VEGF, produced in tumor tissue in responses to hypoxia and other stresses, played a possible role in this selectivity. We compared the actions of ASA404 and VEGF in vitro and also examined the potential for induction of tumor VEGF by ASA404 treatment in vivo. We grew human umbilical vein endothelial cells (HUVEC) on Matrigel and compared in vitro responses to ASA404 and human VEGF using time-lapse microscopy and image analysis. Both ASA404 (30 and 300 µM; 9.9 and 99 µg/ml) and VEGF (50 ng/ml) stimulated the initial formation of 2-dimensional tubular networks on Matrigel. Both ASA404 and VEGF induced actin stress fiber formation in cultured HUVEC's, consistent with increased migration. To determine if there was an in vivo relationship between ASA404 and VEGF expression, mice with Rif-1 tumors (7-9 mm diameter) were treated i.p. with ASA404 (70 µmol/kg; 21 mg/kg) and mRNA was extracted from tumor tissue 4 hours later. VEGF-A mRNA abundance was measured by co-amplification with endogenous 18S mRNA as standard. VEGF-A relative abundance rose from 0.6 ± 0.1 to 1.3 ± 0.1 (p &lt; 0.01). VEGF-B and VEGF-D concentrations also increased but the changes were not significant. The results are consistent with the following model: hypoxia and other stresses in tumor tissue lead to synthesis by both tumor and host cells of VEGF, which increases vascular permeability and partially compromises tumor blood flow. The administration of ASA404 leads to increased tumor vascular permeability and vascular endothelial apoptosis, possibly by a pathway involving p38 kinase, ceramide synthesis and actin stress fiber formation. The resultant decrease in tumor blood flow further increases hypoxia, potentially providing a positive feedback loop by stimulating further VEGF production. These effects, in combination with other cytokines such as tumor necrosis factor that are induced by ASA404, lead to tumor vascular failure. Thus, endogenous VEGF production by tumor tissue may contribute to the antitumor selectivity of ASA404. Further studies addressing the modulatory role of VEGF in the action of ASA404 are warranted.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1660.

Loss of STARD10 expression identifies a group of poor prognosis breast cancers independent of HER2/Neu and triple negative status

The phospholipid transfer protein STARD10 cooperates with c-erbB signaling and is overexpressed in Neu/ErbB2 breast cancers. We investigated if STARD10 expression provides additional prognostic information to HER2/neu status in primary breast cancer. A published gene expression dataset was used to determine relationships between STARD10 and HER2 mRNA levels and patient outcome. The central findings were independently validated by immunohistochemistry in a retrospective cohort of 222 patients with breast cancer with a median follow-up of 64 months. Kaplan-Meier and Cox proportional hazards analyses were used for univariate and multivariate analyses. Patients with low STARD10 or high HER2 tumor mRNA levels formed discrete groups each associated with a poor disease-specific survival (p = 0.0001 and p = 0.0058, respectively). In the immunohistochemical study low/absent STARD10 expression i.e. < or = 10% positive cells was observed in 24 of 222 (11%) tumors. In a univariate model, low/absent STARD10 expression was significantly associated with decreased patient survival (p = 0.0008). In multivariate analyses incorporating tumor size, tumor grade, lymph node status, ER, PR and HER2 status, low STARD10 expression was an independent predictor of death from breast cancer (HR: 2.56 (95% CI: 1.27-5.18), p = 0.0086). Furthermore, low/absent STARD10 expression, HER2 amplification and triple negative status were independent prognostic variables. Loss of STARD10 expression may provide an additional marker of poor outcome in breast cancer identifying a subgroup of patients with a particularly adverse prognosis, which is independent of HER2 amplification and the triple negative phenotype.

The bioreductive prodrug PR-104A is activated under aerobic conditions by human aldo-keto reductase 1C3

PR-104, currently in phase II clinical trials, is a phosphate ester pre-prodrug which is converted in vivo to its cognate alcohol, PR-104A, a prodrug designed to exploit tumor hypoxia. Bioactivation occurs via one-electron reduction to DNA crosslinking metabolites in the absence of oxygen. However, certain tumor cell lines activate PR-104A in the presence of oxygen, suggesting the existence of an aerobic nitroreductase. Microarray analysis identified a cluster of five aldo-keto reductase (AKR) family members whose expressions correlated with aerobic metabolism of PR-104A. Plasmid-based expression of candidate genes identified aldo-keto reductase 1C3 as a novel nitroreductase. AKR1C3 protein was detected by Western blot in 7 of 23 cell lines and correlated with oxic PR-104A metabolism, an activity which could be partially suppressed by Nrf2 RNAi knockdown (or induced by Keap1 RNAi), indicating regulation by the ARE pathway. AKR1C3 was unable to sensitize cells to 10 other bioreductive prodrugs and was associated with single-agent PR-104 activity across a panel of 9 human tumor xenograft models. Overexpression in two AKR1C3-negative tumor xenograft models strongly enhanced PR-104 antitumor activity. A population level survey of AKR1C3 expression in 2,490 individual cases across 19 cancer types using tissue microarrays revealed marked upregulation of AKR1C3 in a subset including hepatocellular, bladder, renal, gastric, and non-small cell lung carcinoma. A survey of normal tissue AKR1C3 expression suggests the potential for tumor-selective PR-104A activation by this mechanism. These findings have significant implications for the clinical development of PR-104.