Pazopanib (GW786034) and cyclophosphamide in patients with platinum-resistant, recurrent, pre-treated ovarian cancer - Results of the PACOVAR-trial

PURPOSE

The prognosis is poor for patients with recurrent, platinum-resistant epithelial ovarian cancer (EOC). Evidence suggests that antiangiogenic treatment modalities could play a major role in EOC. A combined therapy consisting of the investigational oral antiangiogenic agent pazopanib and metronomic oral cyclophosphamide may offer a well-tolerable treatment option to patients with recurrent, previously treated EOC.

PATIENTS AND METHODS

This study was designed as a multicenter phase I trial evaluating the optimal dose as well as activity and tolerability of pazopanib with metronomic cyclophosphamide in the treatment of patients with recurrent, platinum-resistant, previously treated ovarian, peritoneal, or fallopian tube cancer. Here, 50mg cyclophosphamide were combined with 400 to 800mg pazopanib daily.

RESULTS

Sixteen patients were treated; mean age was 66years. At dose levels (DL) I and II, one instance of dose-limiting toxicity (DLT) was seen in one of 6 patients. At DL III, two of four patients showed a DLT, leading to a maximum tolerated dose (MTD) of 600mg pazopanib daily. Median number of administered cycles was 6 (2-13), with three patients being treated for at least 13months. Median progression-free survival (PFS) and overall survival (OS) were 8.35months and 24.95months, respectively. 155 adverse events (AE) occurred, most frequently elevation of liver enzymes, leukopenia, diarrhea and fatigue. Altogether, five serious adverse events (SAE) developed in four patients.

CONCLUSION

Pazopanib 600mg daily p.o. and metronomic cyclophosphamide 50mg daily p.o. is a feasible regimen for patients with recurrent platinum-resistant EOC and showed promising activity in this previously treated patient population.

TRIAL REGISTRATION

Clin.trial.gov registry no.: NCT01238770.

Abstract P1-09-11: Outcome after neoadjuvant chemotherapy in progesterone receptor negative breast cancer patients – A pooled analysis of individual patient data from ten prospectively randomized controlled neoadjuvant trials

Background

The estrogen receptor (ER) as a nuclear transcription factor alters the transcription of estrogen sensitive genes to which the progesterone receptor gene belongs. The ER has also been described to exert non genomic effects by interacting with several cell signalling pathways that do not initially involve increases in gene transcription. These different patterns of action of the ER lead to the assumption that in tumors that utilize the non-genomic ER activity in order to stimulate tumorigenesis and proliferation progesterone receptor (PgR) expression would be decreased or absent. Therefore lack of PgR expression could be a surrogate marker of altered growth factor signalling. The aim of this study was to investigate if PgR expression may act as a predictive factor for response to neoadjuvant chemotherapy and long-term outcome in breast cancer patients.

Methods

5613 patients with primary breast cancer, follow-up, positive ER expression; HER2+ and HER2- from overall 10 (n=9785) German neoadjuvant trials receiving an anthracycline and taxane based chemotherapy were included. The pathologic complete response (pCR)(ypT0, ypN0), long term survival data (disease free survival (DFS), distant disease free survival (DDFS), overall survival (OS) and local recurrence free survival (LRFS)) and early relapse, defined as DFS <37 months, were compared according to their PgR expression, overall and in subgroups defined by HER2.

Results

Tumors lacking PgR expression (1172 patients) were more often of grade 3 (38.4% v 26.3%; p<0.001), tended to have an advanced clinical nodal involvement (6.8% v 4.7%; p=0.004) and were more likely to demonstrate HER2 positivity (36.2% v 22.3%; p<0.001).

pCR rates were significantly higher in PgR negative patients in the entire cohort (13.8% v 7.5%; p<0.001) as well as in the HER2 negative subgroup (11.2% v 5.8%; p<0.001) whereas there was no significant difference in the HER2 positive (22.1% v 18%; p=0.117). After adjusting for known predictive factors in the multivariable logistic regression analysis PgR negativity was an independent predictive factor for pCR overall (OR 1.76; p<0.001) and in the HER2 negative patients (OR 1.99; p<0.001).

PgR negativity was also significantly associated with an early relapse overall (32.8% v 25.7%; p<0.001) and in the subgroups defined by HER2 (HER2- 32.2% v 24.9%; p<0.001 and HER2+ 39.9%v 30.5%; p=0.002).

Patients with PgR negative disease had a significantly worse DFS, OS, DDFS and LRFS (p<0.001, respectively). Multivariable Cox regression analysis revealed that PgR was an independent prognostic factor. This was also observed in the HER2+ and- subgroups. Interestingly, in the PgR negative tumors HER2 status did not influence long-term outcome.

Conclusion

This analysis demonstrates that ER positive and PgR negative tumors represent a specific subset in primary breast cancer patients associated with higher response but also worse long term outcome after neoadjuvant chemotherapy. Interestingly, PgR negativity served as an independent predictive factor for achieving a pCR after neoadjuvant chemotherapy and therefore its status should be considered when deciding on systemic treatment.

Citation Format: van Mackelenberg M, Denkert C, Nekljudova V, Karn T, Schem C, Marme F, Stickeler E, Jackisch C, Hanusch C, Huober J, Fasching P, Blohmer J-U, Kümmel S, Müller V, Schneeweiss A, Untch M, von Minckwitz G, Weber K, Loibl S. Outcome after neoadjuvant chemotherapy in progesterone receptor negative breast cancer patients – A pooled analysis of individual patient data from ten prospectively randomized controlled neoadjuvant trials [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-09-11.

Abstract P2-05-25: Predictive value of ultra-high ESR1 mRNA expression in early breast cancer

Background

Quantitative determination of estrogen receptor mRNA expression in luminal breast tumors is predictive for benefit from adjuvant tamoxifen compared to placebo treatment as has been shown in the large randomized NSABP B-14 trial, while protein determination by IHC or LBA is not (Kim et al JCO 2011). Interestingly, the ultrahigh expression of ESR1 mRNA (above ER score 10 by Oncotype test) has been indicative for tamoxifen benefit. This predictive cut-off value of mRNA expression is significantly higher than the diagnostic cut-off (at ER score 6.5). Here we tested wether the ultrahigh expression of ESR1 mRNA determined by commercial MammaTyper® testing is predictive for survival after neoadjuvant chemotherapy treatment of advanced breast cancer.

Materials and Methods

Pretreatment core cut biopsies from n=54 patients with PBC treated within a randomized phase II trial (2) of anthracyline/taxane based NAC with available clinical follow-up information were examined. RNA was extracted from the FFPE sections and ESR1 mRNA from each section was measured by commercial assays. For technical comparison of ESR1 mRNA values by Oncotype DX versus MammaTyper® from n=113 surgical samples were analyzed by both commercial assays in a blinded fashion. Statistical analysis was performed using the SAS JMP® 9.0.0 software.

Results

Quantification of ESR1 mRNA expression after RNA extraction from separate slices of 113 primary breast tumors and determination by different commercial RT-qPCR assays resulted in high correlation of continuous expression results (Spearman r=0,85; p<0,0001). The rate of ESR1 mRNA negative cases by both methods by predefined diagnostic cut-offs was low in this cohort (1/113 and 6/113, respectively) resulting in high concordance for positive ER status by both methods.The median expression of ER score and ESR1 40-DDCq was high (10,2 and 39,8, respectively) and almost exactly at the predictive ER score cut-off. Hence, the Tamoxifen benefit cut-off of ER score 10 by Oncotype is comparable with a 40-DDCqvalue of 39,6 for ESR1 mRNA determination by MammaTyper®, which resembles an ESR1 mRNA expression 3fold above the diagnostic cut-off. In the independent chemotherapy cohort theoptimal discrimination for overall survival could be achieved by an elevated ESR1 mRNA expression exactly at 39,6 resulting in 100% overall survival for ultra-high expressors and 75 % overall survival for lower ESR1 mRNA expression after 5 years (p=0,006).

Conclusion

Previous data suggest that ultrahigh expression of ESR1 mRNA is predictive for improved overall survival and tamoxifen benefit (1). Here we show that ultrahigh expression of ESR1 mRNA is also prognostic in more advanced breast tumors after neoadjuvant chemotherapy. These findings validate the importance of quantitative determination of estrogen receptor expression and substantiate the understanding of receptor expression being a continuous determinant with indication specific cut-off values. Ultrahigh expression of ESR1 seems to identify a distinct subset of luminal breast tumors with superior prognosis and benefit from tamoxifen treatment. These findings warrant further investigation, which are currently being done in independent large breast cancer cohorts.

Citation Format: Wirtz RM, Scheffen I, Marme F, Laible M, Sclombs K, Schumacher C, Schneeweiss A, Eidt S, Sinn H-P. Predictive value of ultra-high ESR1 mRNA expression in early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-25.

Abstract P1-07-12: Prognosis of clinico-pathological breast cancer subtypes in routine clinical care

Background / Aim: To analyze oncological outcome of breast cancer (BC) subtypes in routine clinical care in specialized breast care units (BCU).

Patients and methods: A prospectively followed cohort of 4110 female cases with primary, non-bilateral, non-metastatic BC treated between 01.01.2003 and 31.12.2012 has been analyzed for the whole cohort and separately for the five routinely used clinico-pathological subtypes (i.e. Luminal A, Luminal B (=Her2 neg.), Luminal B (=Her2 pos.), HER-2, triple negative). The median follow-up of the cohort was 51 month. We calculated estimates for local control rate (LCR), disease-free survival (DFS), distant disease-free survival (DDFS), overall survival (OS) and relative overall survival (ROS).

5 year outcome results referred to 5 different endpoints (using Kaplan-Meier method) of all patients with primary, non-metastatic, non-bilateral breast cancer treated at Heidelberg Breast Care Unit between 01.01.2003 and 31.12.2012 All patients (including in-situ)Patients with invasive cancer (excluding in-situ) n=4102 (including 499 in-situ cases)n = 3603LCR [%] (95% CI)96.1 (95.6 ; 96.6)96.1 (95.7 ; 96.5)DFS [%] (95% CI)85.0 (84.2 ; 85.8)83.7 (82.8 ; 84.6)DDFS [%] (95% CI)86.9 (86.1 ; 87.7)85.7 (84.8 ; (86.6)OS [%] (95% CI)91.3 (90.5 ; 92.2)90.5 (89.6 ; 91.4)ROS [%] (95% CI)95.5 (94.3 ; 96.7)94.7 (93.4 ; 96.0)CI, confidence interval; LCR, local recurrence rate; DFS, disease-free survival; DDFS, distant disease-free survival; OS, observed overall survival; ROS, relative (age adjusted) overall survival

Outcome results referred to 5 different endpoints (using Kaplan-Meier method) according to clinico-pathological tumor subtype or in-situ tumor. Results in percent at 5 years (95% CI).invasive cancer (n = 34541) Lum A-likeLum B1-likeLum B2-likeHER2+Triple negativeCIS (n = 499)LCR [%] (95% CI)99.1 (98.7 ; 99.5)95.2 (-)**95.0 (86.3 ; 100)90.5 (-)89.6 (87.1 ; 92.1)96.2 (94.3 ; 98.1)DFS [%] (95% CI)92.2 (90.9 ; 93.5)80.1 (78.6 ; 81.6)79.0 (71.0 ; 86.0)77.0 (-)69.1 (66.4 ; 71.8)93.0 (91.3 ; 94.7)DDFS [%] (95% CI)92.9 (91.6 ; 94.2)82.2 (80.5 ; 83.9)82.8 (76.5 ; 89.1)83.3 (-)72.2 (70.7 ; 73.7)95.6 (94.4 ; 96.8)OS [%] (95% CI)95.1 (94.1 ; 96.1)88.7 (86.6 ; 90.8)92.5 (87.5 ; 97.5)85.6 (79.9 ; 91.3)78.5 (76.4 ; 80.6)96.9 (95.2 ; 98.6)ROS [%] (95% CI)100.0 (98.5 ; 100)93.4 (90.7 ; 96.1)96.0 (91.2 ; 100)88.8 (81.4 ; 96.2)80.1 (75.1 ; 85.1)100.0 (97.8 ; 100)

Results: LCR, DFS, DDFS, OS and ROS over 5 years for the whole cohort of invasive cases were 96.1%, 83.7%, 85.7%, 90.5% and 94.7%, respectively. Luminal A tumors were the most frequent (44.7%) and showed the best outcome with LCR, OS and ROS over 5 years at 99.1%, 95.1% and 100.0%, respectively; while triple negative tumors presented the poorest outcome with LCR, OS and ROS over 5 years at 89.6%, 78.5% and 80.1%, respectively.

Conclusions: This outcome analysis of a large cohort of patients with primary BC diagnosed, treated and prospectively followed on a routine basis at a specialized BCU in Germany confirmed general and detailed clinico-pathological subtype outcome data of clinical trials.

Citation Format: Hennigs A, Heil J, Gondos A, Riedel F, Marme F, Sinn H-P, Schirmacher P, Kauczor H-U, Debus J, Golatta M, Schtz F, Sohn C, Schneeweiss A. Prognosis of clinico-pathological breast cancer subtypes in routine clinical care. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-12.

Common germline polymorphisms associated with breast cancer-specific survival

INTRODUCTION

Previous studies have identified common germline variants nominally associated with breast cancer survival. These associations have not been widely replicated in further studies. The purpose of this study was to evaluate the association of previously reported SNPs with breast cancer-specific survival using data from a pooled analysis of eight breast cancer survival genome-wide association studies (GWAS) from the Breast Cancer Association Consortium.

METHODS

A literature review was conducted of all previously published associations between common germline variants and three survival outcomes: breast cancer-specific survival, overall survival and disease-free survival. All associations that reached the nominal significance level of P value <0.05 were included. Single nucleotide polymorphisms that had been previously reported as nominally associated with at least one survival outcome were evaluated in the pooled analysis of over 37,000 breast cancer cases for association with breast cancer-specific survival. Previous associations were evaluated using a one-sided test based on the reported direction of effect.

RESULTS

Fifty-six variants from 45 previous publications were evaluated in the meta-analysis. Fifty-four of these were evaluated in the full set of 37,954 breast cancer cases with 2,900 events and the two additional variants were evaluated in a reduced sample size of 30,000 samples in order to ensure independence from the previously published studies. Five variants reached nominal significance (P <0.05) in the pooled GWAS data compared to 2.8 expected under the null hypothesis. Seven additional variants were associated (P <0.05) with ER-positive disease.

CONCLUSIONS

Although no variants reached genome-wide significance (P <5 x 10(-8)), these results suggest that there is some evidence of association between candidate common germline variants and breast cancer prognosis. Larger studies from multinational collaborations are necessary to increase the power to detect associations, between common variants and prognosis, at more stringent significance levels.

Common non-synonymous SNPs associated with breast cancer susceptibility: findings from the Breast Cancer Association Consortium

Candidate variant association studies have been largely unsuccessful in identifying common breast cancer susceptibility variants, although most studies have been underpowered to detect associations of a realistic magnitude. We assessed 41 common non-synonymous single-nucleotide polymorphisms (nsSNPs) for which evidence of association with breast cancer risk had been previously reported. Case-control data were combined from 38 studies of white European women (46 450 cases and 42 600 controls) and analyzed using unconditional logistic regression. Strong evidence of association was observed for three nsSNPs: ATXN7-K264R at 3p21 [rs1053338, per allele OR = 1.07, 95% confidence interval (CI) = 1.04-1.10, P = 2.9 × 10(-6)], AKAP9-M463I at 7q21 (rs6964587, OR = 1.05, 95% CI = 1.03-1.07, P = 1.7 × 10(-6)) and NEK10-L513S at 3p24 (rs10510592, OR = 1.10, 95% CI = 1.07-1.12, P = 5.1 × 10(-17)). The first two associations reached genome-wide statistical significance in a combined analysis of available data, including independent data from nine genome-wide association studies (GWASs): for ATXN7-K264R, OR = 1.07 (95% CI = 1.05-1.10, P = 1.0 × 10(-8)); for AKAP9-M463I, OR = 1.05 (95% CI = 1.04-1.07, P = 2.0 × 10(-10)). Further analysis of other common variants in these two regions suggested that intronic SNPs nearby are more strongly associated with disease risk. We have thus identified a novel susceptibility locus at 3p21, and confirmed previous suggestive evidence that rs6964587 at 7q21 is associated with risk. The third locus, rs10510592, is located in an established breast cancer susceptibility region; the association was substantially attenuated after adjustment for the known GWAS hit. Thus, each of the associated nsSNPs is likely to be a marker for another, non-coding, variant causally related to breast cancer risk. Further fine-mapping and functional studies are required to identify the underlying risk-modifying variants and the genes through which they act.

Genetic predisposition to in situ and invasive lobular carcinoma of the breast

Invasive lobular breast cancer (ILC) accounts for 10-15% of all invasive breast carcinomas. It is generally ER positive (ER+) and often associated with lobular carcinoma in situ (LCIS). Genome-wide association studies have identified more than 70 common polymorphisms that predispose to breast cancer, but these studies included predominantly ductal (IDC) carcinomas. To identify novel common polymorphisms that predispose to ILC and LCIS, we pooled data from 6,023 cases (5,622 ILC, 401 pure LCIS) and 34,271 controls from 36 studies genotyped using the iCOGS chip. Six novel SNPs most strongly associated with ILC/LCIS in the pooled analysis were genotyped in a further 516 lobular cases (482 ILC, 36 LCIS) and 1,467 controls. These analyses identified a lobular-specific SNP at 7q34 (rs11977670, OR (95%CI) for ILC = 1.13 (1.09-1.18), P = 6.0 × 10(-10); P-het for ILC vs IDC ER+ tumors = 1.8 × 10(-4)). Of the 75 known breast cancer polymorphisms that were genotyped, 56 were associated with ILC and 15 with LCIS at P<0.05. Two SNPs showed significantly stronger associations for ILC than LCIS (rs2981579/10q26/FGFR2, P-het = 0.04 and rs889312/5q11/MAP3K1, P-het = 0.03); and two showed stronger associations for LCIS than ILC (rs6678914/1q32/LGR6, P-het = 0.001 and rs1752911/6q14, P-het = 0.04). In addition, seven of the 75 known loci showed significant differences between ER+ tumors with IDC and ILC histology, three of these showing stronger associations for ILC (rs11249433/1p11, rs2981579/10q26/FGFR2 and rs10995190/10q21/ZNF365) and four associated only with IDC (5p12/rs10941679; rs2588809/14q24/RAD51L1, rs6472903/8q21 and rs1550623/2q31/CDCA7). In conclusion, we have identified one novel lobular breast cancer specific predisposition polymorphism at 7q34, and shown for the first time that common breast cancer polymorphisms predispose to LCIS. We have shown that many of the ER+ breast cancer predisposition loci also predispose to ILC, although there is some heterogeneity between ER+ lobular and ER+ IDC tumors. These data provide evidence for overlapping, but distinct etiological pathways within ER+ breast cancer between morphological subtypes.

FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium

BACKGROUND

Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.

METHODS

Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.

RESULTS

Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95% confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2.

CONCLUSION

Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2.

Abstract P1-08-07: High tumor CD68 mRNA content (intratumoral macrophages) predicts response to neoadjuvant chemotherapy

Background

Immune cell infiltrates have been shown to play a prominent role with regard to prognosis of node negative breast cancer (Schmidt et al 2008). Moreover, it has been shown that B-cells and T-Cells are of particular importance for the response to chemotherapy (Schmidt et al. 2012). However, the role of macrophages remains unclear. It has been assumed, that tumor-associated macrophages play a role in promoting tumorigenesis. Still their role with regard to therapy prediction is unknown. Here we tested wether the infiltration of macrophages is associated with the response to neoadjuvant chemotherapy.

Materials and Methods

Pretreatment core cut biopsies from n = 100 patients with PBC treated within a randomized phase II trial (1) of anthracyline/taxane based NAC were examined. RNA from formalin-fixed, paraffin embedded (FFPE) routine biopsies were extracted using a bead-based extraction method (STRATIFYER XTRAKT kits). CD68 and ESR1, PGR, HER2, Ki67 as well as CALM2 as a house keeping gene were measured via a multiplex quantitative RT-PCR (RT-qPCR). Correlation analyses and partitioning tests were performed using the SAS JMP® 9.0.0 software.

Results

CD68 mRNA exhibited a normal data distribution (Median expression 40-DCT 34,66) in the core needle biopsies of advanced breast tumors. CD68 mRNA correlated strongly with Ki67 mRNA levels (Spearman r = 0,46; p&lt;0,001), whereas there is virtually no correlation with other classical biomarkers such as ESR1, PGR and HER2. Partitioning analysis revealed that CD68 mRNA levels are superior to the previously and prospectively validated response markers ESR1 mRNA and HER2 mRNA. When using the median mRNA expression as an objective cut-off measurement no tumor having low CD68 mRNA expression did respond to chemotherapy, while 22% of the CD68 positive tumors responded by pathological complete response (ypT0ypN0). Based on molecular subtyping into Luminal, HER2 positive and Triple-Negative with predefined Cut-Off values for ESR1mRNA and HER2 mRNA levels, high CD68 were particularly informative within luminal tumors (22% pCR versus 0% pCR rate) and Triple negative tumors (38% pCR versus 0% pCR rate).

Conclusion

The presence of macrophages indicates tumors being sensitive to chemotherapy beyond the prospectively validated ESR1 and HER2 mRNA determinations (2), both in luminal and triple negative tumors. The mRNA expression levels of CD68 provide additional information beyond conventional subtyping and might therefore be useful for early assessment of non-response to chemotherapy und subsequent treatment planning.

1) Schneeweiss et al, Ann Oncol 2011

2) Denkert et al, Ann Oncol 2013.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-07.

Fine-scale mapping of the FGFR2 breast cancer risk locus: putative functional variants differentially bind FOXA1 and E2F1

The 10q26 locus in the second intron of FGFR2 is the locus most strongly associated with estrogen-receptor-positive breast cancer in genome-wide association studies. We conducted fine-scale mapping in case-control studies genotyped with a custom chip (iCOGS), comprising 41 studies (n = 89,050) of European ancestry, 9 Asian ancestry studies (n = 13,983), and 2 African ancestry studies (n = 2,028) from the Breast Cancer Association Consortium. We identified three statistically independent risk signals within the locus. Within risk signals 1 and 3, genetic analysis identified five and two variants, respectively, highly correlated with the most strongly associated SNPs. By using a combination of genetic fine mapping, data on DNase hypersensitivity, and electrophoretic mobility shift assays to study protein-DNA binding, we identified rs35054928, rs2981578, and rs45631563 as putative functional SNPs. Chromatin immunoprecipitation showed that FOXA1 preferentially bound to the risk-associated allele (C) of rs2981578 and was able to recruit ERα to this site in an allele-specific manner, whereas E2F1 preferentially bound the risk variant of rs35054928. The risk alleles were preferentially found in open chromatin and bound by Ser5 phosphorylated RNA polymerase II, suggesting that the risk alleles are associated with changes in transcription. Chromatin conformation capture demonstrated that the risk region was able to interact with the promoter of FGFR2, the likely target gene of this risk region. A role for FOXA1 in mediating breast cancer susceptibility at this locus is consistent with the finding that the FGFR2 risk locus primarily predisposes to estrogen-receptor-positive disease.

Genome-wide association studies identify four ER negative-specific breast cancer risk loci

Estrogen receptor (ER)-negative tumors represent 20-30% of all breast cancers, with a higher proportion occurring in younger women and women of African ancestry. The etiology and clinical behavior of ER-negative tumors are different from those of tumors expressing ER (ER positive), including differences in genetic predisposition. To identify susceptibility loci specific to ER-negative disease, we combined in a meta-analysis 3 genome-wide association studies of 4,193 ER-negative breast cancer cases and 35,194 controls with a series of 40 follow-up studies (6,514 cases and 41,455 controls), genotyped using a custom Illumina array, iCOGS, developed by the Collaborative Oncological Gene-environment Study (COGS). SNPs at four loci, 1q32.1 (MDM4, P = 2.1 × 10(-12) and LGR6, P = 1.4 × 10(-8)), 2p24.1 (P = 4.6 × 10(-8)) and 16q12.2 (FTO, P = 4.0 × 10(-8)), were associated with ER-negative but not ER-positive breast cancer (P > 0.05). These findings provide further evidence for distinct etiological pathways associated with invasive ER-positive and ER-negative breast cancers.

Abstract P3-06-08: Ki-67 mRNA as a predictor for response to neoadjuvant chemotherapy in primary breast cancer

Background: Pathologic complete response (pCR, ypT0/is) is one of the strongest prognostic factors for primary breast cancer (PBC) in the setting of neoadjuvant chemotherapy (NAC). Factors predictive for response to NAC can help to stratify for an individualized therapy. As chemotherapeutic agents are most active in highly proliferative tumors, it was the aim of the present study to evaluate the potential of Ki-67 as a single proliferation marker, quantitatively measured on the mRNA or protein level, to predict response of PBC to NAC.

Material and methods: Pretreatment core cut biopsies from n=72 patients with PBC treated within a randomized phase II trial (1) of anthracylin/taxane based NAC were examined. Immunohistochemistry was performed for the Ki67 antigen on an automated IHC platform (Dako Techmate 500). Ki-67 were assessed either by visual scoring (vIHC) or by quantitative image analysis (qIHC). For quantitative IHC analysis tumor proliferation was analyzed after tumor stroma segmentation using the Aperio Image Analysis toolbox. RNA was extracted from formalin-fixed, paraffin embedded (FFPE) routine biopsies using a bead-based extraction method (STRATIFYER XTRAKT kits). Ki-67, TOP2A and RACGAP1 as well as CALM2 as a house keeping gene were measured via a multiplex quantitative RT-PCR (qPCR). Kaplan-Meier survival estimates, patitioning test and correlation analyses were performed using the SAS JMP® 9.0.0 software.

Results: There was only a moderate correlation between Ki-67 mRNA or Ki-67 measured by immunohistochemistry (IHC) and histologic grade (Spearman r = 0.52 p &lt; 0.0001; r = 0.23 p = 0.033, respectively). Conventional visual scoring and qIHC correlated well (r = 0,78 p &lt; 0,0001), while qPCR and qIHC correlated moderately (r = 0,50 p &lt; 0,0001). For Ki-67 determined by visual scoring of standard IHC there was an optimal discrimination at a cut-off of 20% stained nuclei with regard to chemotherapy response. Yet, the difference between pCR-rates for high and low Ki-67 on IHC was non-significant, with 16.3% and 12.5% pCRs in the IHC Ki-67 high and low group, respectively. For Ki-67 IHC analysed by quantitative image analysis there was optimal cut-off at 35% stained nuclei resulting in 37,5% versus 8,7% pCR rate and 54% of pCRs classified correctly. For qPCR determination, high Ki-67 mRNA expression was associated with a high pCR-rate of 36.4% as opposed to 5.8% in tumors with low Ki-67 mRNA levels and 82% classified correctly.

Conclusion: High Ki-67 mRNA expression measured by RT-qPCR was predictive for the achievement of pCR to NAC and in this respect was superior to Ki-67 determined by vIHC or qIHC. This is consistent with data on Ki-67 IHC as a predictor of pCR on larger neoadjuvant cohorts (1). RT-qPCR based measurements of Ki-67 mRNA ensures an objective and highly reproducible quantification of proliferative activity from FFPE tissue from routine core cut biopsies. As such it seems to be more robust and meaningful compared to protein-based determination of Ki-67 by IHC, both by visual scoring or quantitative image analysis.

1) Schneeweiss et al, Ann Oncol 2011 2) Fasching et al., BMC Cancer 2011

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-08.

Association of the fibroblast growth factor receptor-4 (FGFR4) Gly388Arg polymorphism with clinical and pathological response to primary systemic therapy (PST) for early breast cancer (EBC)

525

Background: The FGFR4 Arg388 genotype has recently been shown to be associated with decreased disease free survival after adjuvant systemic therapy for EBC and thus therapy resistance (Harbeck et al, J Clin Oncol. 2006). Primary systemic therapy (PST) for EBC allows in-vivo chemosensitivity testing. Pathological complete response (pCR) in the breast following PST is associated with improved survival. We evaluated the FGFR4 Gly388Arg polymorphism as a predictive factor for response to PST for EBC in the setting of a prospective, randomized phase 2 trial. Methods: Patients (pts, n = 257) with T2–4/N0–2/M0 EBC were randomized to 4 cycles (cy) A 60 mg/m2 + C 600 mg/m2 day (d) 1 every three weeks (q3w) followed by 4 cy D 100 mg/m2 d1 q3w, or 4 cy A 60 mg/m2 + P 500 mg/m2 on d1 q3w followed by 4 cy D 100 mg/m2 d1 q3w, stratified by hormone receptor (HR) status. Surgery was performed after last chemotherapy. Genotyping was performed using a Taqman Genotyping assay. The genotype was confirmed by RFLP-PCR for 50% of samples with 100% congruence. Results: Genotype was available for 252 of 257 pts enrolled into this study. Using Fisher´s Exact Test there was no correlation between genotype and clinical tumour size (cT), HR status, HER2neu status, grading, menopausal status or triple negative phenotype. The G/G genotype correlates significantly with clinically positive axillary lymph nodes before chemotherapy (p = 0.03). Considering all pts the G/G genotype (vs G/A + A/A) is associated with a significantly lower overall response rate (ORR)(OR 0,47; 65% vs 80%; p = 0.03). Separate analysis of treatment arms showed a significant correlation between the G/G genotype (vs other genotypes) and a lower pCR rate (OR 0.33; 12.5% vs 30.4%; p = 0.04), clinical complete response (p = 0.02) and ORR (OR 0.25; p = 0.01) in the AC-D arm, whereas there was no correlation for pts treated with AP-D. Conclusions: This study provides important evidence that the FGFR4 genotype might serve as a valuable predicitve marker for response to PST with AC-D for EBC.

No significant financial relationships to disclose.

Phase I study of apoptosis gene modulation with oblimersen within preoperative chemotherapy in patients with primary breast cancer

e11576

Background: The expression of the Bcl-2 protein confers resistance to chemotherapy mediated apoptotic signals in patients with breast cancer. The development of chemo sensitizing drugs may result in new treatment options. We investigated the effects of Bcl-2 down-regulation by the Bcl-2 antisense oligodeoxynucleotide oblimersen in breast tumor biopsies. Oblimersen targets Bcl-2 mRNA, thereby down regulates Bcl-2 protein translation, and enhances the antitumor effects of sub therapeutic doses of docetaxel. Methods: Within a phase I trial we administered escalating doses of oblimersen (3/5/7mg/kg/day) as continuous infusion on day 1–7 in combination with standard dosed docetaxel, doxorubicin, cyclophosphamide (TAC) on day 5 as preoperative chemotherapy in 28 patients with T2–4 breast cancers. Effects of oblimersen were evaluated in tumor biopsies and peripheral blood mononuclear cells (PBMCs) 4 days after start of oblimersen continuous infusion and before TAC treatment by quantitative microfluidic real-time polymerase chain reaction (RT-PCR). Read-outs consisted in measurement of Bcl-2 mRNA modulations and of 18 other putative predictive markers. Results: Two out of 13 patients showed a diminution of Bcl-2 transcripts after 4 days of treatment with oblimersen 5 mg/kg/day. PBMCs could not be evaluated as a surrogate tissue, because no qualified RNA could be isolated. Conclusions: Nevertheless, we demonstrated the feasibility to process clinical samples and to obtain good quality RNA from tumor biopsies, and indicated the potential of oblimersen to lower Bcl-2 mRNA in breast cancer.

No significant financial relationships to disclose.