Tumor-infiltrating lymphocytes in HER2-positive breast cancer treated with neoadjuvant chemotherapy and dual HER2-blockade

Tumor-infiltrating lymphocytes (TILs) have been associated with outcomes in HER2-positive breast cancer patients treated with neoadjuvant chemotherapy and trastuzumab. However, it remains unclear if TILs could be a prognostic and/or predictive biomarker in the context of dual HER2-targeting treatment. In this study, we evaluated the association between TILs and pathological response (pCR) and invasive-disease free survival (IDFS) in 389 patients with stage II-III HER2 positive breast cancer who received neoadjuvant anthracycline-containing or anthracycline-free chemotherapy combined with trastuzumab and pertuzumab in the TRAIN-2 trial. Although no significant association was seen between TILs and pCR, patients with TIL scores ≥60% demonstrated an excellent 3-year IDFS of 100% (95% CI 100-100), regardless of hormone receptor status, nodal stage and attainment of pCR. Additionally, in patients with hormone receptor positive disease, TILs as a continuous variable showed a trend to a positive association with pCR (adjusted Odds Ratio per 10% increase in TILs 1.15, 95% CI 0.99-1.34, p = 0.070) and IDFS (adjusted Hazard Ratio per 10% increase in TILs 0.71, 95% CI 0.50-1.01, p = 0.058). We found no interactions between TILs and anthracycline treatment. Our results suggest that high TIL scores might be able to identify stage II-III HER2-positive breast cancer patients with a favorable prognosis.

Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

BluePrint molecular subtypes predict response to neoadjuvant pertuzumab in HER2-positive breast cancer

BACKGROUND

The introduction of pertuzumab has greatly improved pathological complete response (pCR) rates in HER2-positive breast cancer, yet effects on long-term survival have been limited and it is uncertain which patients derive most benefit. In this study, we determine the prognostic value of BluePrint subtyping in HER2-positive breast cancer. Additionally, we evaluate its use as a biomarker for predicting response to trastuzumab-containing neoadjuvant chemotherapy with or without pertuzumab.

METHODS

From a cohort of patients with stage II-III HER2-positive breast cancer who were treated with neoadjuvant chemotherapy and trastuzumab with or without pertuzumab, 836 patients were selected for microarray gene expression analysis, followed by readout of BluePrint standard (HER2, Basal and Luminal) and dual subtypes (HER2-single, Basal-single, Luminal-single, HER2-Basal, Luminal-HER2, Luminal-HER2-Basal). The associations between subtypes and pathological complete response (pCR), overall survival (OS) and breast cancer-specific survival (BCSS) were assessed, and pertuzumab benefit was evaluated within the BluePrint subgroups.

RESULTS

BluePrint results were available for 719 patients. In patients with HER2-type tumors, the pCR rate was 71.9% in patients who received pertuzumab versus 43.5% in patients who did not (adjusted Odds Ratio 3.43, 95% CI 2.36-4.96). Additionally, a significantly decreased hazard was observed for both OS (adjusted hazard ratio [aHR] 0.45, 95% CI 0.25-0.80) and BCSS (aHR 0.46, 95% CI 0.24-0.86) with pertuzumab treatment. Findings were similar in the HER2-single subgroup. No significant benefit of pertuzumab was seen in other subtypes.

CONCLUSIONS

In patients with HER2-type or HER2-single-type tumors, pertuzumab significantly improved the pCR rate and decreased the risk of breast cancer mortality, which was not observed in other subtypes. BluePrint subtyping may be valuable in future studies to identify patients that are likely to be highly sensitive to HER2-targeting agents.

Iatrogenic endometriosis harbors somatic cancer-driver mutations

STUDY QUESTION

Does incisional endometriosis (IE) harbor somatic cancer-driver mutations?

SUMMARY ANSWER

We found that approximately one-quarter of IE cases harbor somatic-cancer mutations, which commonly affect components of the MAPK/RAS or PI3K-Akt-mTor signaling pathways.

WHAT IS KNOWN ALREADY

Despite the classification of endometriosis as a benign gynecological disease, it shares key features with cancers such as resistance to apoptosis and stimulation of angiogenesis and is well-established as the precursor of clear cell and endometrioid ovarian carcinomas. Our group has recently shown that deep infiltrating endometriosis (DE), a form of endometriosis that rarely undergoes malignant transformation, harbors recurrent somatic mutations.

STUDY DESIGN, SIZE, DURATION

In a retrospective study comparing iatrogenically induced and endogenously occurring forms of endometriosis unlikely to progress to cancer, we examined endometriosis specimens from 40 women with IE and 36 women with DE. Specimens were collected between 2004 and 2017 from five hospital sites in either Canada, Germany or the Netherlands. IE and DE cohorts were age-matched and all women presented with histologically typical endometriosis without known history of malignancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Archival tissue specimens containing endometriotic lesions were macrodissected and/or laser-capture microdissected to enrich endometriotic stroma and epithelium and a hypersensitive cancer hotspot sequencing panel was used to assess for presence of somatic mutations. Mutations were subsequently validated using droplet digital PCR. PTEN and ARID1A immunohistochemistry (IHC) were performed as surrogates for somatic events resulting in functional loss of respective proteins.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, we detected somatic cancer-driver events in 11 of 40 (27.5%) IE cases and 13 of 36 (36.1%) DE cases, including hotspot mutations in KRAS, ERBB2, PIK3CA and CTNNB1. Heterogeneous PTEN loss occurred at similar rates in IE and DE (7/40 vs 5/36, respectively), whereas ARID1A loss only occurred in a single case of DE. While rates of detectable somatic cancer-driver events between IE and DE are not statistically significant (P > 0.05), KRAS activating mutations were more prevalent in DE.

LIMITATIONS, REASONS FOR CAUTION

Detection of somatic cancer-driver events were limited to hotspots analyzed in our panel-based sequencing assay and loss of protein expression by IHC from archival tissue. Whole genome or exome sequencing, or epigenetic analysis may uncover additional somatic alterations. Moreover, because of the descriptive nature of this study, the functional roles of identified mutations within the context of endometriosis remain unclear and causality cannot be established.

WIDER IMPLICATIONS OF THE FINDINGS

The alterations we report may be important in driving the growth and survival of endometriosis in ectopic regions of the body. Given the frequency of mutation in surgically displaced endometrium (IE), examination of similar somatic events in eutopic endometrium, as well as clinically annotated cases of other forms of endometriosis, in particular endometriomas that are most commonly linked to malignancy, is warranted.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by a Canadian Cancer Society Impact Grant [701603, PI Huntsman], Canadian Institutes of Health Research Transitional Open Operating Grant [MOP-142273, PI Yong], the Canadian Institutes of Health Research Foundation Grant [FDN-154290, PI Huntsman], the Canadian Institutes of Health Research Project Grant [PJT-156084, PIs Yong and Anglesio], and the Janet D. Cottrelle Foundation through the BC Cancer Foundation [PI Huntsman]. D.G. Huntsman is a co-founder and shareholder of Contextual Genomics Inc., a for profit company that provides clinical reporting to assist in cancer patient treatment. R. Aguirre-Hernandez, J. Khattra and L.M. Prentice have a patent MOLECULAR QUALITY ASSURANCE METHODS FOR USE IN SEQUENCING pending and are current (or former) employees of Contextual Genomics Inc. The remaining authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

A specific gene expression signature for visceral organ metastasis in breast cancer

BACKGROUND

Visceral organ metastasis is associated with poor survival outcomes in terms of metastasis free- and overall survival in breast carcinomas. Identification of a gene expression profile in tumours that selects a subpopulation of patients that is more likely to develop visceral organ metastases will help elucidate mechanisms for the development of distant metastases and could be of clinical value. With this study we aimed to determine genomic predictors that would help to distinguish breast cancer patients with more likelihood to develop visceral metastasis.

METHODS

Gene expression profiling data of 157 primary tumours from breast cancer patients who developed distant metastases were analyzed and differentially expressed genes between the group of tumours with visceral metastasis and the those without visceral metastases were identified. Published data were used to validate our findings. Multivariate logistic regression tests were applied to further investigate the association between the gene-expression-signature and clinical variables. Survival analyses were performed by the Kaplan-Meier method.

RESULTS

Fourteen differentially expressed genes (WDR6, CDYL, ATP6V0A4, CHAD, IDUA, MYL5, PREP, RTN4IP1, BTG2, TPRG1, ABHD14A, KIF18A, S100PBP and BEND3) were identified between the group of tumours with and without visceral metastatic disease. Five of these genes (CDYL, ATP6V0A4, PREP, RTN4IP1 and KIF18A) were up-regulated and the other genes were down-regulated. This gene expression signature was validated in the training and in the independent data set (p 2.13e- 08 and p 9.68e- 06, respectively). Multivariate analyses revealed that the 14-gene-expression-signature was associated with visceral metastatic disease (p 0.001, 95% CI 1.43-4.27), independent of other clinicopathologic features. This signature has been also found to be associated with survival status of the patients (p < .001).

CONCLUSION

We have identified an unique gene expression signature which is specific to visceral metastasis. This 14-gene-expression-signature may play a role in identifying the subgroup of patients with potential to develop visceral metastasis.

Abstract P6-17-19: What to do with trastuzumab therapy after achieving radiological complete remission (rCR) in HER2+ metastatic breast cancer (MBC)?

Intro MBC is generally considered incurable, but patients with HER2+ disease treated with trastuzumab do relatively well and some have an exceptional durable response and survive over 10 years. We analyzed the clinical-pathological characteristics associated with long-term survival in patients with HER2+ MBC treated with trastuzumab. In addition, we studied the effect of stopping trastuzumab in case of rCR.

Methods We included all patients with HER2+ MBC treated with first- or second-line trastuzumab-based palliative therapy between January 2000 and December 2014 in 8 Dutch hospitals (Netherlands Cancer Institute, Erasmus Medical Center, Albert Schweitzer Hospital, Reinier de Graaf Hospital, Amphia Hospital, St. Antonius Hospital, Ikazia Hospital, Haga Hospital). Patients were identified through the Netherlands Cancer Registry and linkage with the institutes' tumor registries. Data was collected from medical records using case record forms. Primary endpoint was overall survival (OS), defined as first-date of MBC until death due to any cause. Kaplan-Meier survival estimates were calculated and multivariable Cox-regression models used to identify prognostic factors for improved survival. Time to progression (TTP) after achieving rCR for patients who continued and stopped trastuzumab and breast cancer specific survival were secondary outcomes.

Results We included 744 patients (median age 53, range 24-87). Median follow-up (FU) was 109 months (range 0-178). Clinical factors associated with improved survival in multivariable analyses were single-organ metastases, ER-positivity, no skin or liver metastases, no prior trastuzumab, local therapy of metastatic disease and achievement of rCR. In line with our first single center analyses1, achievement of rCR was the strongest predictor of improved survival (multivariable HR 0.30, 95%CI 0.20-0.46). RCR was observed in 71 patients (10%), of whom 60 had been treated with trastuzumab and chemotherapy, 9 with trastuzumab and hormonal therapy, and 2 with hormonal therapy. In patients with rCR the estimated 10-year OS was 53% versus 7% in patients who did not achieve rCR (p&lt;0.001).

Thirty patients stopped trastuzumab after achieving rCR. Median time between onset of rCR and last gift of trastuzumab in these patients was 6 months (0-132). Twenty-one patients (70%) remain in complete remission after a median FU of 75 months (range 54-90) since onset of rCR. Nine patients experienced disease progression after a median time of 14 months (range 9-62) since last gift of trastuzumab. Of these, 8 patients died due to MBC and one again achieved an ongoing rCR. Out of 39 patients who continued trastuzumab after achieving rCR, 12 are in ongoing remission after a median FU of 71 months (range 51-91). In this group median TTP was 14 months (range 5-23).

Conclusion Achieving rCR is strongly associated with long-term survival in patients with HER2+ MBC. Seventy percent of patients who stopped trastuzumab after achieving rCR remained in remission, suggesting this can be an attractive approach in selected patients. External validation of these findings is required, however, as well as additional analyses to characterize the patients -and their tumors- who achieved rCR.

1 Steenbruggen, CancerRes 2017

Citation Format: Steenbruggen TG, Bouwer NI, Smorenburg CH, Rier HN, Jager A, Beelen KJ, ten Tije AJ, de Jong PC, Drooger JC, Holterhues C, Horlings HM, Sanders J, Levin M-D, Sonke GS. What to do with trastuzumab therapy after achieving radiological complete remission (rCR) in HER2+ metastatic breast cancer (MBC)? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-19.

Abstract P2-07-04: Prognostic value of residual cancer burden (RCB), neo-bioscore and neoadjuvant response index (NRI) to evaluate response to neoadjuvant trastuzumab-based therapy in HER2-positive breast cancer (BC)

Intro Pathological complete response (pCR) to neoadjuvant systemic therapy is associated with favorable long-term outcome. As pCR is not an optimal surrogate marker for outcome, other tools were developed to predict long-term outcome more accurately, including the RCB4, NRI3, and Neo-Bioscore5. We evaluated the prognostic value of these tools in a cohort of patients with HER2+ BC with the aim of selecting a group of patients with residual disease but a similar long-term outcome as patients achieving pCR.

Methods We included all patients with stage II-III HER2+ BC who were treated with trastuzumab-based neoadjuvant therapy and surgery in the Netherlands Cancer Institute between November 2004 and December 2016. Patients were identified from the institutes' tumor registry and data was collected from the patients' records. To assess RCB scores surgical specimens (breast and axilla tissue) of patients without pCR were retrospectively reviewed. NRI and Neo-Bioscore were calculated based on original pathology reports.

Primary endpoint was recurrence-free interval (RFI), defined as time since diagnosis of BC till locoregional or distant recurrence or death from BC, whatever came first. Cox proportional models were used with transformations of RCB, NRI, and Neo-Bioscore. In addition, we evaluated at which cut-off point the NRI could select patients with a similar good prognosis as patients who achieved a pCR, defined by the same lower bound of the 95%CI of the 5-year RFI estimate for the pCR-group.

Results 283 women were included, 149 (53%) with HER2+/ER+ BC. 28% received dual HER2-blockade. Median follow-up was 66 months (range 11-148). 157 patients (55%) achieved a pCR in breast and axilla; predicted 5-year RFI for this group was 91% (95%CI 86-96), HR no-pCR vs pCR 2.19, 95%CI 1.07-4.47. Table 1 shows the predicted 5-year RFI and HR for RCB classes. The HR of an RFI event increases gradually for lower NRI values compared to NRI of 1 and gets more steep near NRI values of 0. Patients with a NRI of ≥0.80-0.99 have a 5-year RFI estimate of 90% (95%CI 86-96), HR 1.1 (95%CI 0.6-1.9) compared to patients with NRI of 1 (which is pCR). Table 2 shows the predicted 5-year RFI and HR for the Neo-Bioscore.

Table 1RCB classes, estimated 5-year RFI and HRRCBn% 5-year RFI95% CIHR95% CI016392.688.397.111113990.385.295.61.330.672.6526278.469.488.53.181.427.1131135.316.476.113.605.3034.81

Table 2Neo-Bioscore classes, predicted 5-year RFI and HRNeo-Bioscoren% 5-year RFI95% CIHR95% CI01998.795.510011115392.486.099.36.100.9240.5229384.977.493.012.670.76210.4037289.983.896.58.200.62108.2041974.962.989.222.331.76283.445329.410.384.095.206.271446.64610.601.00406.2619.558442.21

Conclusions We show that in a HER2+ BC cohort the RCB and NRI are able to identify a subgroup of patients with limited residual disease after neoadjuvant therapy with similar good prognosis as patients with pCR and therefore may not benefit from additional adjuvant therapy.

References

1 Cortazar Lancet 2014

2 FDA Regist 2014

3 Rodenhuis Ann Oncol 2010

4 Symmans JCO 2007

5 Jeruss JCO 2008

6 Mittendorf JAMA Oncol 2016

Citation Format: Steenbruggen TG, van Seijen M, Janssen LM, van Ramshorst MS, van Werkhoven E, Lips EH, Vrancken-Peeters M-JT, Horlings HM, Wesseling J, Sonke GS. Prognostic value of residual cancer burden (RCB), neo-bioscore and neoadjuvant response index (NRI) to evaluate response to neoadjuvant trastuzumab-based therapy in HER2-positive breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-07-04.

Epithelial-to-mesenchymal transition status of primary breast carcinomas and its correlation with metastatic behavior

Background

Epithelial-to-mesenchymal transition (EMT) has been implicated as an important step in the development of distant metastases. We therefore wished to study EMT status of primary breast carcinomas from patients who during follow-up developed distant metastases.

Methods

mRNA expression profiles of primary breast carcinoma samples (n = 151) from patients who developed metastatic disease were analyzed and EMT status was designated using a previously described EMT-core signature. EMT status of the primary tumor was correlated to clinicopathological characteristics, molecular subtypes, metastasis pattern, chemotherapy response and survival outcomes. In addition, using immunohistochemistry, the expression levels of several proteins implicated in EMT were studied (CDH1, CDH2, NAT1, SNAI2, TWIST1, VIM, and ZEB1) compared with the designated EMT status and survival.

Results

Utilizing the 130-gene-EMT-core signature, 66.2% of the primary tumors in the current study was assessed as EMT-activated. In contrast to our expectations, analyses revealed that 84.6% of Luminal A tumors, 65.1% of Luminal B tumors, and 55.6% of HER2-like had an activated EMT status, compared to only 25% of the basal-type tumors (p < 0.001). EMT status was not correlated to the pattern of metastatic disease, metastasis-specific survival, and overall survival. Similarly, there was not a significant association between EMT status of the primary tumor and chemotherapy response in the metastatic setting. Immunostaining for NAT1 and TWIST1 correlated with the EMT status (p 0.003 and p 0.047, respectively). Multivariate analyses showed that NAT1 and TWIST1 staining was significantly associated with EMT status regardless of the estrogen receptor status of the tumors (p values: 0.020 and 0.027, respectively).

Conclusions

The EMT status of breast cancers, as defined by the presence of a core EMT gene expression signature is associated with non-basal-type tumors, but not with the pattern of distant metastasis. Of several potential immunohistochemical EMT markers, only NAT1 and TWIST1 expression levels were associated with the gene expression-based EMT status.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-05089-5) contains supplementary material, which is available to authorized users.

High prevalence of oncogenic MYD88 and CD79B mutations in diffuse large B-cell lymphomas presenting at immune-privileged sites

Activating mutations in CD79 and MYD88 have recently been found in a subset of diffuse large B-cell lymphoma (DLBCL), identifying B-cell receptor and MYD88 signalling as potential therapeutic targets for personalized treatment. Here, we report the prevalence of CD79B and MYD88 mutations and their relation to established clinical, phenotypic and molecular parameters in a large panel of DLBCLs. We show that these mutations often coexist and demonstrate that their presence is almost mutually exclusive with translocations of BCL2, BCL6 and cMYC, or Epstein–Bar virus infection. Intriguingly, MYD88 mutations were by far most prevalent in immune-privileged site-associated DLBCL (IP-DLBCL), presenting in central nervous system (75%) or testis (71%) and relatively uncommon in nodal (17%) and gastrointestinal tract lymphomas (11%). Our results suggest that MYD88 and CD79B mutations are important drivers of IP-DLBCLs and endow lymphoma-initiating cells with tissue-specific homing properties or a growth advantage in these barrier-protected tissues.

Integrative molecular and functional profiling of ERBB2-amplified breast cancers identifies new genetic dependencies

Overexpression of the receptor tyrosine kinase ERBB2 (also known as HER2) occurs in around 15% of breast cancers and is driven by amplification of the ERBB2 gene. ERBB2 amplification is a marker of poor prognosis, and although anti-ERBB2-targeted therapies have shown significant clinical benefit, de novo and acquired resistance remains an important problem. Genomic profiling has demonstrated that ERBB2+ve breast cancers are distinguished from ER+ve and 'triple-negative' breast cancers by harbouring not only the ERBB2 amplification on 17q12, but also a number of co-amplified genes on 17q12 and amplification events on other chromosomes. Some of these genes may have important roles in influencing clinical outcome, and could represent genetic dependencies in ERBB2+ve cancers and therefore potential therapeutic targets. Here, we describe an integrated genomic, gene expression and functional analysis to determine whether the genes present within amplicons are critical for the survival of ERBB2+ve breast tumour cells. We show that only a fraction of the ERBB2-amplified breast tumour lines are truly addicted to the ERBB2 oncogene at the mRNA level and display a heterogeneous set of additional genetic dependencies. These include an addiction to the transcription factor gene TFAP2C when it is amplified and overexpressed, suggesting that TFAP2C represents a genetic dependency in some ERBB2+ve breast cancer cells.

P4-09-13: External Validation of Adjuvant! Online Breast Cancer Prognosis Tool. Improvement Is Still Needed

Introduction: AdjuvantOnline is a web-based application designed to provide 10 years survival probability patients with breast cancer. Few validation studies have underlined some limitations, particularly an overestimation of the prognosis among certain subgroups of patients. Moreover, several predictors such as HER2 over expression status and proliferation markers have not been assessed in Adjuvant! original study. We provide the validation of AdjuvantOnline algorithm on two breast cancer datasets collected from two large European cancer centres, and we determined whether the accuracy of AdjuvantOnline is improved by others well known prognostic factors.

Material and Methods: The French data set is composed of 456 women with early breast cancer, treated at the Institut Curie between 1995 and 1996. The dutch data set is composed of 295 women less that 52 years treated at the Netherlands Cancer Institute between 1984 and 1995. Agreement between observation and Adjuvant! prediction was checked by testing that the calibration slope was equal to 1. Logistic models were performed to evaluate whether risk factors adds significant prognostic information, including AdjuvantOnline a priori information as an offset.

Results: Ten years survival status was known for 383 patients in the French data set and 247 patients in the Dutch data set. Adjuvant! prediction was globally well calibrated in the French data set (observed survival 86%, predicted survival 85%), but was overestimated in high grade, HER2 positive and Ki67 &gt; 20% subgroups. HER2 status, Mitotic Index, Ki67 and treatment type were strongly associated with 10-year survival, even considering AdjuvantOnline a priori information. In the Dutch data set, the overall 10-year survival was overestimated by AdjuvantOnline (observed 66%, predicted 79%), particularly in patients less than 40 years old.

Conclusion: AdjuvantOnline needs to be updated to adjust overoptimistic results in young and high grade patients, and should consider candidates, such as Ki67, HER2 and Mitotic Index.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-13.

Left-sided native valve Staphylococcus aureus endocarditis

Despite improved diagnostic tools and expanded treatment options, left-sided native valve endocarditis caused by Staphylococcus aureus infection remains a serious and destructive disease. The high morbidity and mortality, however, can be reduced by early recognition, correct diagnosis, and appropriate treatment. In the following article, we discuss the clinical presentation, diagnostic workup and treatment of infective endocarditis, thereby reviewing the current guidelines. Blood cultures and echocardiography are the cornerstones of diagnosis in identifying infective endocarditis but are no substitute for clinical judgement. The modified Duke criteria may facilitate the diagnostic process, but clinical evaluation remains crucial.

ER Status and Immune Module Are Central Determinants of HER2 Amplified Infiltrative Breast Carcinoma Prognosis and Pathologic Complete Response

IntroductionGene expression profiling of invasive breast cancer has resulted in highlighting three main categories of breast cancer [luminal, basal, HER2] with very specific features. It has been shown that these subtypes differ in their response to neaoadjuvant systemic treatment, axillary lymph node involvement, metastasis pattern and time to metastasis. The aim of this study was to focus on gene-expression profile analysis of HER2 positive breast carcinoma to assess how the molecular subtype classification applies to the HER2+ve samples; whether subgroups of patients that have different prognosis can be identified and how subgroups can be identified that differ with respect to the likelihood to achieve pathologic complete response (pCR) after neoadjuvant systemic treatment?Materials and MethodWe selected breast carcinomas reported to have a HER2+ve status (IHC and CISH) from patients treated between January 1990 and December 2006 at the Netherlands Cancer Institute. 113 tumor samples were hybridized on the Human Genome Oligo Set Version 3.0 arrays. We identified 205 HER2+ve samples from 4 public microarrays datasets and 33 HER2+ve samples from one public neoadjuvant systemic treatment microarrays dataset.ResultsWe applied the molecular subtype classification to the whole datasets and found major classification instability. 43.3% of the HER2+ve samples were classified as “HER2 subtype”, 26% as “basal-like subtype”, and 21.9% as “luminal-like subtype”. The molecular subtype classification was not correlated to prognosis. Of the prognostic variables tested, only ER status was to the development of distant metastasis (IHC, HR=0.53 [0.36-0.77], p=0.0009). We identified a set of 109 ReporterID's highly enriched in gene ontology annotations link to the Immune Response and correlated to the prognosis of HER2+ve breast carcinoma (Inactivated Immune Module, HR=4.21 [1.94-9.17], logrank pvalue=8.1E-05). The Immune Module Signature was associated with prognosis of the HER2+ve samples in both ER positive and ER negative breast cancer. We validated this Immune Module signature combined with ER status on 205 independent samples.We applied the same classification tree to 33 samples from patients who were assessed for response to neo-adjuvant systemic chemotherapy (Anthracyclin-based) and showed an association between the Immune Module Signature combined with ER status and pCR rate (ER+ve Inactivated Immune Module 12.5% pCR, ER-ve Activated Immune Module 70% pCR, pvalue=0.1).ConclusionWe have shown that HER2+ve breast cancer samples often are not classified as HER2-like by gene expression profiling and that ER (IHC) status determines two major subgroups. We provide new evidence that an immune response relate gene expression classifier has prognostic impact in HER2+ve breast cancer; and that this classifier is potentially correlated to the pCR rate after neoadjuvant systemic treatment in HER2+ve breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4037.

Integrative Molecular Profiling of Triple Negative Breast Cancers Identifies Potential Therapeutic Targets Including Amplifications of FGFR2

Triple negative breast cancers (TNBCs) have a relatively poor prognosis emphasising the need to identify new subtype specific target therapies. Based on the concept of oncogene addiction, we searched for potential therapeutic targets by identifying genes consistently over-expressed when amplified in TNBC. Fifty six TNBCs were subjected to high resolution tiling path microarray-based comparative genomic hybridisation (aCGH); out of these cases, 24 were also subjected to genome-wide microarray-based mRNA expression analysis. TNBCs showed a high level of genetic instability, with recurrent regions of amplification (&gt;4 copies) included multiple regions on 1q and 8q, 3q25, 10p14, 10q26, 13q34, 15q26 and 19q12-19q13. Integration of aCGH and expression data revealed 38 genes that were significantly overexpressed when amplified. This list includes known oncogenes and potential therapeutic targets, such as MCL1 (1q21.2), FGFR2 (10q26.3), BUB3 (10q26.3), RAB20 (13q34), PKN1 (19p13.12), and NOTCH3 (19p13.12). To validate FGFR2 as a therapeutic target, we screened a panel of cell lines, by western blotting and aCGH, and identified two TNBC cell lines with FGFR2 amplification. In these cell lines FGFR2 was constitutively active in a ligand independent manner, and RNA interference-mediated silencing of FGFR2 selectively decreased survival of cell lines harbouring FGFR2 amplification. Likewise FGFR2 amplified cell lines were highly sensitive to FGFR tyrosine kinase inhibitor PD173074 (IC50 &lt;20nM). Treatment with PD173074 induced apoptosis in amplified cell lines, as did treatment with PI3 kinase inhibitors LY294002 and BEZ-235 suggesting that apoptosis resulted from inhibition of AKT signalling. Examination of publically available CGH data sets confirmed FGFR2 amplification in 4% (5/124 95%CI 1.3-9.2%) of TNBC, with no cases of FGFR2 amplification in other subtypes (0/150, p=0.02). Our results suggest that FGFR2 amplification is a therapeutic target in a small subset of TNBCs.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3147.

Different effects of insulin-like growth factor-1 receptor expression on prognosis of estrogen receptor positive versus triple-negative invasive ductal breast carcinoma

3546

Background: The insulin-like growth factor type 1 receptor (IGF-1R) is involved in progression and sensitivity to systemic treatment of breast cancer. Moreover, targeted inhibition of IGF-1R is likely to be beneficial in systemic treatment. However, it is unknown how to select patients for IGF-1R targeted therapy. Therefore, we studied the relation between IGF-1R expression and prognosis in invasive ductal breast carcinomas. Methods: Immunohistochemistry was performed on tumor tissue of a consecutive cohort of 429 female patients treated for operable primary invasive ductal breast carcinoma. TMA sections were stained with antibodies against IGF1-R, insulin receptor (IR), ER, PR, HER-2, epidermal growth factor receptor (EGFR) and phosphorylated-Akt (p-Akt). Cytoplasmic and membranous IGF-1R staining were scored separately, as the relevance of IGF-1R cellular localization is yet unknown. Associations between IGF-1R expression with clinical and tumor characteristics were evaluated in a multivariate Cox regression model. To study in more detail the prognostic role of IGF-1R expression in triple negative invasive ductal carcinomas (TN IDCs), 51 TN IDCs from the series described above were combined with 64 TN IDCs from an independent dataset with similar patient and clinico-pathological characteristics. Results: Patients with tumors expressing both ER and cytoplasmic IGF-1R have a longer disease free survival (HR = 0.20; 95% CI 0.07 - 0.63; p-value = 0.006) and breast cancer specific survival (HR = 0.20, 95% CI 0.07 - 0.63, p-value = 0.002), independent of other known prognostic factors. Conversely, in the combined series of 105 TN IDCs, cytoplasmic IGF-1R expression was associated with a shorter disease free survival (HR = 2.29; 95% CI 1.08 - 4.48, p-value = 0.03). In a multivariate model including known prognostic factors, cytoplasmic IGF-1R expression was nearly significantly related to a shorter disease free survival (HR 2.06; 95% CI 0.95 - 4.47; p = 0.07). Conclusions: The favorable versus unfavorable association with prognosis of IGF-1R expression in ER positive versus TN IDCs may provide new opportunities to select patients for IGF-1R targeted therapy.

No significant financial relationships to disclose.

Microarray-based determination of ER, PR and HER2 receptor status: validation and comparison with IHC assessments

Abstract #3007

Background&#x2028; In breast cancer patients the level of expression of estrogen receptor (ER), progesterone receptor (PR) and HER2 is predictive for prognosis and/or treatment response. However, differences in assessment methods and interpretation can substantially affect the accuracy and reproducibility of the results. Previously, we have determined the association between immunohistochemistry (IHC) and mRNA levels for ER, PR and HER2, and have confirmed the accuracy of microarray readout on &gt;400 samples. In the current study we describe the use of this microarray based readout on prospectively collected samples. We compared these readouts with multiple IHC and fluorescent in situ hybridization (FISH) assessments generated in various hospitals and a CLIA-certified reference laboratory and developed a microarray based test called TargetPrint™.&#x2028; Methods&#x2028; Gene expression data for ER, PR and HER2 were obtained by analysis of 100 breast carcinomas that have been collected prospectively within the RASTER study. Samples were stratified as receptor positive or negative using thresholds for ER, PR and HER2 mRNA levels. IHC assessment was performed (1) according to local standards of the hospital from where the sample originated, (2) by the central laboratory of the Netherlands Cancer Institute, and (3) at an independent reference laboratory using FDA-approved procedures and ASCO/CAP guidelines. A tumor was classified positive for ER and PR when ≥10% of tumor cells showed positive staining. HER2 IHC status was scored as 0, 1+, 2+ or 3+; a score of 3+ was considered positive. In case of 2+ samples, a FISH was performed to assess final HER2 amplification status. The cohort used in this study was pre-selected to include about two-third ER and PR positive samples and one-third HER2 positive samples.&#x2028; Results&#x2028; Multiple microarray readouts were highly reproducible (Pearson correlation 0.991) and resulted in 67, 61 and 39 percent positive samples for ER, PR and HER2, respectively. Comparison of microarray results with IHC (including FISH for HER2) performed at the three centers indicated highly similar results for receptor readout with a concordance of 92, 93 and 92% for ER; 84, 81 and 86% for PR; and 93, 95 and 94% for HER2. Overall misclassification rates between microarray and IHC readout were low for ER (0.08) and HER2 (0.06) and quite low for PR (0.14), and were comparable to the misclassification rates between the three IHC methods.&#x2028; Conclusion&#x2028; A microarray-based assessment of ER, PR and HER2 in relation to mRNA levels gives results comparable to multiple IHC methods and FISH and provides an objective and more quantitative assessment of tumor receptor status than IHC alone. Using TargetPrint™ for microarray readouts for hormone and HER2 receptor in addition to standard IHC will improve molecular characterization of breast cancer tissue.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3007.

Robust prognostic value of a knowledge-based proliferation signature across large patient microarray studies spanning different cancer types

Tumour proliferation is one of the main biological phenotypes limiting cure in oncology. Extensive research is being performed to unravel the key players in this process. To exploit the potential of published gene expression data, creation of a signature for proliferation can provide valuable information on tumour status, prognosis and prediction. This will help individualising treatment and should result in better tumour control, and more rapid and cost-effective research and development. From in vitro published microarray studies, two proliferation signatures were compiled. The prognostic value of these signatures was tested in five large clinical microarray data sets. More than 1000 patients with breast, renal or lung cancer were included. One of the signatures (110 genes) had significant prognostic value in all data sets. Stratifying patients in groups resulted in a clear difference in survival (P-values <0.05). Multivariate Cox-regression analyses showed that this signature added substantial value to the clinical factors used for prognosis. Further patient stratification was compared to patient stratification with several well-known published signatures. Contingency tables and Cramer's V statistics indicated that these primarily identify the same patients as the proliferation signature does. The proliferation signature is a strong prognostic factor, with the potential to be converted into a predictive test. Furthermore, evidence is provided that supports the idea that many published signatures track the same biological processes and that proliferation is one of them.

Refinement of breast cancer classification by molecular characterization of histological special types

Most invasive breast cancers are classified as invasive ductal carcinoma not otherwise specified (IDC NOS), whereas about 25% are defined as histological 'special types'. These special-type breast cancers are categorized into at least 17 discrete pathological entities; however, whether these also constitute discrete molecular entities remains to be determined. Current therapy decision-making is increasingly governed by the molecular classification of breast cancer (luminal, basal-like, HER2+). The molecular classification is derived from mainly IDC NOS and it is unknown whether this classification applies to all histological subtypes. We aimed to refine the breast cancer classification systems by analysing a series of 11 histological special types [invasive lobular carcinoma (ILC), tubular, mucinous A, mucinous B, neuroendocrine, apocrine, IDC with osteoclastic giant cells, micropapillary, adenoid cystic, metaplastic, and medullary carcinoma] using immunohistochemistry and genome-wide gene expression profiling. Hierarchical clustering analysis confirmed that some histological special types constitute discrete entities, such as micropapillary carcinoma, but also revealed that others, including tubular and lobular carcinoma, are very similar at the transcriptome level. When classified by expression profiling, IDC NOS and ILC contain all molecular breast cancer types (ie luminal, basal-like, HER2+), whereas histological special-type cancers, apart from apocrine carcinoma, are homogeneous and only belong to one molecular subtype. Our analysis also revealed that some special types associated with a good prognosis, such as medullary and adenoid cystic carcinomas, display a poor prognosis basal-like transcriptome, providing strong circumstantial evidence that basal-like cancers constitute a heterogeneous group. Taken together, our results imply that the correct classification of breast cancers of special histological type will allow a more accurate prognostication of breast cancer patients and facilitate the identification of optimal therapeutic strategies.