Abstract P1-03-05: A comprehensive molecular analysis of medullary breast carcinoma: A model of immunomodulatory triple negative breast cancer subtype

Medullary breast carcinoma (MBC) is a rare subtype of triple negative breast cancer (TNBC)with specific genomic features within the spectrum of basal-like carcinoma. The frequent association between BRCA constitutive mutation and MBC phenotype has been reported previously. In this study including 19 MBC and 36 non-MMB basal-like carcinoma (BLC), we refine the genomic and transcriptomic knowledge about this entity. Using pan genomic Affymetrix genome-wide human SNP6.0 array, we show that i/ MBC harbour more copy number alterations and losses of heterozygocity than BLC and that ii/ the high frequency of BRCAness genomic trait among MBC. Unsupervised and supervised analysis of GeneChip Uman Genome U133 Plus 2.0 Array transcriptomic generated data confirmed that MBC clearly differ from BLC in terms of gene expression level, with 92 genes overexpressed and 154 genes underexpressed in MBC over BLC. Immune response and inflammatory response are the most differentially represented pathways in MBC over BLC. Pro apoptotic gene BCLG is by far the more overexpressed gene in MBC. A validation study conducted with RT-QPCR among 526 breast tumors form all molecular subtype confirmed the specificity of BCLG overexpression in MBC, which was confirmed at protein level using immunohistochemisytry. Moreover, we show that a vast majority of MBC belong o the immunomodulatory TNBC subtype according to Lehman et al. Finally, we confirm the better prognosis of MBC toward BLC. Our observations epitomize the importance of developing DNA repair targeting drugs and immunotherapy based trials in order to improve the outcome of such a specific entity.

Citation Format: Romero P, Deniziaut G, Benhamo V, Fuhrmann L, Berger F, Bhalshankar J, Gruel N, MacGrogan G, Popova T, Manié E, Stern M-H, Stoppa-Lyonnet D, Rouzier R, Delattre O, Bieche I, Vincent-Salomon A. A comprehensive molecular analysis of medullary breast carcinoma: A model of immunomodulatory triple negative breast cancer subtype [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 P1-03-05.

Abstract P1-15-04: Luminal B Lobular Carcinomas In Situ Have a Higher Risk of Relapse Compared to the Other Molecular Types of Lobular Carcinomas In Situ: Results from a Pilot Retrospective Single Institution Study

Aims: To determine the molecular subtypes existing in a retrospective series of classical lobular carcinoma in situ (LCIS) and to evaluate the risk of relapse in the different groups. To assess by immunohistochemistry the expression of stem cell markers in LCIS.

Material and methods: A series of 58 LCIS have been retrospectively selected in our files according to the availability of clinical data. The expression of E-cadherin (clone 4A2C7, Invitrogen), ER (clone 6F11, Novocastra), PR (clone 1A6, Novocastra), ERBB2 (clone CB11, Novocastra), EGFR (clone 31G7, Zymed), KI67 (MIB1), CD44 (1563C11, Thermo Fisher Scientific), CD24 (clone SN3b, Thermo Fisher Scientific) and ALDH1 (clone 44/ALDH, BD transduction Laboratories) were determined on whole tissue sections for 47 patients with available paraffin blocks. For ER, PR, EGFR and Ki67, 10% of positive cells were used as cut-off. For ERBB2, the interpretation was performed according to the ASCO guidelines for invasive carcinomas. The molecular subtypes were defined as luminal A: ER+ ERBB2- and Ki67<10%; luminal B: ER+, Ki67 >10% or ERBB2+; ERBB2 ER-and ERBB2 3+; basal-like: ER-PR-ERBB2-and EGFR+. All patients’ charters were reviewed and clinical data was recorded. All of the patients underwent tumorectomy without any radiation therapy.

Results: Median age was 50 yrs (min 31; max 72). The majority of the lesions were diagnosed by microcalcifications on mammography (62% of the cases) and treated by lumpectomy (98%). The majority of the lesions were classical LCIS (97%). The majority of the cases were E-cadherin negative (53%), the other cases presenting a weak staining of 10 to 80% of the cells, ER +ve (91%), PR +ve (68%), ERBB2 -ve (100%), KI67 low (81%), EGFR-ve (89%). A total of 33 cases were defined as luminal A (72%), 9 cases as luminal B (20%) and 4 cases were ER-ve/ERBB2-ve. At five years, all patients were alive, 1/33 luminal A experienced a relapse contrasting with 4 out of 9 luminal B (1 LCIS, 3 invasive carcinomas including 2 ductal and 1 lobular) (p= 0.004). The majority of the cases was CD44 +ve (93%), CD24 -ve (57%) and ALDH1 -ve (74%). No statistically significant link was observed between the stem cell phenotype defined as CD44+/CD24-/ALDH1+ and a risk of relapse.

Conclusions: Classical LCIS are in majority of luminal A type (72%). 20% of LCIS are luminal B and present a risk of relapse higher than luminal A LCIS. In this retrospective pilot study, for the first time to our knowledge, we observed a higher risk of relapse associated with the luminal B phenotype of LCIS. This observation needs to be confirmed in a larger series but could contribute to improve the clinical management of classical LCIS patients.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-15-04.

Abstract P4-04-04: Polarity Abnormalities in Invasive Carcinomas of the Breast: Analysis of Invasive Micropapillary Carcinoma of the Breast

Aims: Invasive micropapillary carcinomas (IMPC) are rare (<2% of all invasive breast carcinomas) and characterized by clusters of cells with an inverted polarity surrounded by a clear space that separate them from the extracellular matrix. These tumors harbor vascular invasion and axillary lymph node involvement in more than 70% of the cases. We performed a detailed analysis of cellular polarity in a series of 25 IMPC to get insight in the putative role of proteins involved in the maintenance of cellular polarity in that carcinoma subtype.

Methods: Polarity analysis has been performed by immunohistochemistry on a tissue-micro-array of a series of twenty-five invasive micropapillary carcinomas. Apical (p-ERM, a marker of phosphorylated ezrin, moesin and radixin, aPKCz, MUC1 and GM130, a marker of the golgi apparatus), basal (collagen IV), or baso-lateral (EGFR, E-cadherin, b-catenin and ERBB2) markers were assessed.

Results: Apical markers MUC1, aPKCz, P-ERM were expressed at the external cellular pole in 88% (22/25), 60% (15/25) and 40% (10/25) of the cases respectively. Notably, 15/25 (60%) were p-ERM negative. Twenty-four cases/25 (96%) demonstrated a GM130 localisation at the external pole of the cells, with an abnormal internal and external localisation of the labelling in 15/24 positive cases (62%). Finally, 24% (6/25) cases presented all these apical markers located at the external part of the cells and 92% (23/25) had at least one of the apical markers in external position. The large majority of the cases (96%; 24/25) demonstrated no collagen IV labelling at the external part of the cell clusters. Intercellular junction proteins E-cadherin and b-catenin were expressed in all cases with a complete absence of staining at the apical inverted pole for both markers. Interestingly, a thick and strong labelling was observed for E-cadherin and for b-catenin in 36% (9/25) and 92% (23/25) of the cases respectively. EGFR was negative in 24 out of the 25 cases (96%). In contrast, ERBB2 was overexpressed in 6/25 (24%) of cases with a membranous ERBB2 labelling except external at the inverted apical pole. EGFR and ERBB2 are considered in normal cells as a baso-lateral marker. Conclusion: IMPC present a clear inverted apical pole MUC-1 and/or aPKCz and/or phospho-ERM positive with the golgi apparatus facing the external membrane of cell clusters, oriented towards the clear space and the extracellular matrix. The intercellular junctions in IMPC are abnormal with a thick E-cadherin and b-catenin labelling compared to normal cells. These abnormal cell orientation and junctions could be a consequence of molecular alterations that are currently being analysed in our laboratory, and that could explain the high frequency of loco-regional lymphatic tumor extension observed in IMPC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-04-04.

Identification of three-genomic regions prognostic signature in small node-negative breast carcinomas

Abstract #1081

Background: The purpose of this study was to identify a genomic signature of early metastatic recurrence, in order to predict accurately breast carcinomas clinical outcome and to select patients with node negative and small tumor size (<3cm) who would benefit from adjuvant chemotherapy.
 Patients and methods: Using genome-wide BAC-PAC Genomic Comparative Hybridization (CGH) array (1kb), we analyzed a training set of 78 patients. All patients had invasive ductal carcinomas and were initially treated by surgery and radiotherapy, without chemotherapy. The validation was performed on an independent test set of 90 patients. The training and tests sets were composed of respectively 53 and 58 patients disease-free survivors at 60 months (good prognosis group), and by 25 and 32 patients with distant metastatic recurrence before 48 months (poor prognosis group). In the training set, a signature was established as a logistic multivariate model of regions containing contiguous BAC clones with statistically different ratios and median frequencies of gains and losses between the poor and the good prognosis groups. This signature was then validated using the independent test set to evaluate its accuracy to classify T0T1T2N0 patients according to their outcome.
 Results: The training test identified a prognostic signature defined by 3 genomic regions, located on the 2p (38.3 to 40.9Mb), 3p (32 to 80.3Mb), and 8q (78.8 to 128.9Mb) chromosomes. In the test set, 90% of patients of favourable outcome were ER +ve and 88% were PR +ve, compared to 62% and 55% in the poor outcome group, respectively. In the test set, our signature was highly informative to identify patients that developed distant metastases before 48 months: the rate of patients well classified was 0.74, CI (95%): [0.64; 0.83], with a specificity of 95%, CI (95%): [86%; 99%]. On Kaplan-Meier analysis, the poor-prognosis genomic signature group of patients had a RR of 3.5 of metastatic relapse (log rank test p<0.001).
 Conclusions: Our signature, validated on an independent series of small T0T1T2N0 and on a majority of ER/PR positive tumors, may provide a robust and accurate tool to identify, in addition to classical parameters, patients who would benefit from adjuvant medical treatments. The comparison of this genomic signature with RNA based signatures and clinico-pathological parameters, is currently being investigated.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1081.

Consistent TP53 mutations in BRCA1 and sporadic basal-like breast tumors, while infrequent in luminal BRCA1 tumors

Abstract #4070

Breast tumors with a germline mutation of BRCA1 (BRCA1 tumors) and Basal-Like Carcinoma (BLC) have been shown to be associated with a high rate of TP53 mutations. Because it has also been shown that BRCA1 tumors frequently display a basal-like phenotype, we sought to determine whether TP53 mutations were correlated to the hereditary BRCA1 mutated status or to the particular histological type of these tumors. We first explored the status of the TP53 gene in a series of 28 BRCA1 BLCs using immunohistochemistry, direct sequencing of the coding sequence, and functional assay in yeast (FASAY), and compared it to the status of TP53 in 27 series of sporadic (non hereditary) BLCs. With this sensitive approach, TP53 was found consistently mutated in BRCA1 (28/28) and sporadic (26/27) BLCs. However, mutation spectrum was different, in particular with a much higher rate of insertion/deletion in BRCA1 BLCs (12/27) than in the sporadic group (2/25). Secondly, we analyzed the incidence of TP53 mutations in 10 BRCA1 luminal tumors, using the same strategy. Surprisingly, only 3 of these 10 tumors were mutated, a frequency similar to that found in matched sporadic luminal tumors. In conclusion, TP53 mutation is a mandatory event in BRCA1 or sporadic BLCs, but not a common feature of BRCA1 luminal tumors.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4070.

Genomic and transcriptomic differences between lobular and luminal ductal invasive carcinoma

Abstract #2039

Background: Invasive lobular carcinomas (ILCs) of the breast are characterized by morphological and phenotypical features such as small, non cohesive, estrogens receptors positive cells, low proliferation rates with a metastatic spreading in numerous and different unusual metastatic sites as compared to invasive ductal carcinomas (IDCs) (Ferlicot et al, 2004). We have previously shown that ILCs presented the same outcome than IDCs (Sastre-Garau et al, 1996). Beyond E-cadherin genomic inactivation, little is known about the underlying genomic and transcriptomic alterations that may discriminate both subtypes.
 Aims of the study: To get an insight into ILC biological specificities, we performed a combined genomic (aCGH), transcriptomic (Affymetrix U133A+B) and phenotypic analysis of a series of 24 lobular carcinomas and compared it to a series of 41 ER-positive IDCs.
 Results: Analysis of genomic copy number showed that ILCs and IDCs shared gains of the 1q11-q43 region and losses of 16q12.1-q24.2 and 17pter-p13.1 regions. ILCs presented the 22q12-q13 loss but not the 16pter-p11.2 gain and 11q23-q24 loss as observed in IDCs. Eight different regions of high level amplifications were found in 29% of ILC cases (7/24 cases). Only one region of amplification was recurrent and observed in 5 out of 24 tumors (21% of the cases). This recurrent region of amplification was localized on the 11q13.2 region and encompassed the Cyclin D1 (CCND1) and Cortactin (CTTN) genes. ILCs and IDCs had comparable overall survival rates, however, unsupervised hierarchical clustering of transcriptomic data showed that ILCs and IDCs clustered apart. Genes involved in cell adhesion and motility, lipid/fatty transport and metabolism and electron transport were differentially expressed between the two groups.
 Conclusions: This integrated analysis emphasized the biological differences between ILC and IDC and highlighted genes of interest that could be useful for diagnosis, and could be new putative therapeutical targets.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2039.

Bypassing tumor-specific and bispecific antibodies: triggering of antitumor immunity by expression of anti-FcgammaR scFv on cancer cell surface

We have developed a novel immunostimulatory molecule against tumor cells, composed of an anti-FcgammaRIII (CD16) scFv fused to the platelet-derived growth factor receptor (PDGFR) transmembrane region. This fusion molecule was stably expressed on the tumor cell surface and retained the ability of the parental antibody to bind soluble CD16. Tumor cells expressing anti-CD16 scFv triggered the release of IL-2 by Jurkat-CD 16/gamma cells and of TNFalpha by monocytes when co-cultured with these cells. Furthermore, NK cells could kill scFv-transfected HLA+ class I H1299 lung carcinoma tumor cells, but not the parental cells, indicating that anti-CD16 scFv tumor expression prevents the killer inhibitory receptor (KIR)-mediated inhibition of NK cell cytotoxicity. This anti-CD16 scFv tumor expression also enhanced tumor phagocytosis by IFNgamma-activated macrophages, a mechanism known to induce a protective long-term adaptative immunity to tumors. In vivo Winn tests performed in SCID mice showed that the expression of anti-CD16 scFv on tumor cells, but not of the negative control anti-phOx scFv, prevented tumor cell growth. Thus, expression of FcR antibodies or other FcR-specific ligands on tumor cells represents a novel and potent antibody-based gene therapy approach, which may have clinical applications in cancer

Purification of soluble recombinant human FcgammaRII (CD32)

The present study describes the methodology used to purify human recombinant low-affinity FcgammaRIIa2 produced in E. coli and to evaluate its binding to surface IgG. The recombinant molecule was purified by a two-step chromatographic procedure, including affinity chromatography using IV.3 anti-FcgammaRIIa1/2 immunosorbent, followed by gel filtration chromatography. Using this method, the purified recombinant FcgammaRIIa2 was 99% pure. It exhibited an isoeletric point of 5.2. Binding studies demonstrated a specific binding of the purified recombinant molecule to surface IgG expressed by human B cells. Thus, we have set up a method which allows to purify functional human recombinant FcgammaRIIa2 for further characterization of its biological activities.

Ras and p53 intracellular targeting with recombinant single-chain Fv (scFv) fragments: a novel approach for cancer therapy?

Intracellular expression of recombinant antibodies allows one to interfere with the functions of oncogenic molecules expressed in various cell compartments and has therefore a vast clinical potential in cancer therapy. We inhibited the functions of oncogenic Ras mutant forms by intracellular expression of a neutralizing single-chain antibody (scFv). In vitro studies indicated that the scFv is expressed in the cytosol of Xenopus laevis oocytes and of tumor cells, blocks ras-mediated activation processes, and induces tumor cell death. In vivo studies performed using scFv cDNA inserted into an adenoviral vector showed that the scFv dramatically affects tumor growth. Second, intracellular expression of scFvs directed against p53 indicated that these antibody fragments can be successfully targeted to cell nucleus, bind p53, and partially restore the transcriptional activity of p53 mutants in human tumor cells. Thus, intracellular scFvs directed against oncogenic molecules may represent a new class of antitumor agents.

Immunoglobulin variable regions usage by B-lymphocytes infiltrating a human breast medullary carcinoma

Breast medullary carcinoma are heavily infiltrated by B-lymphocytes and associated with a good prognosis despite their high histological grade. We investigated the Ig repertoire of B-lymphocytes infiltrating one such tumour. A single cell suspension was obtained from a tumor specimen by enzymatic digestion. VH, Vkappa, and Vlambda regions were amplified by RT-PCR using mixtures of primers optimized to maximize the diversity of the PCR products. They were then cloned and sequenced. Analysis of 9 VH, 5 Vkappa, and 10 Vlambda sequences using the Kabat database indicated that several VH and VL region subgroups (I, II and III) are expressed by B-lymphocytes infiltrating this tumor. The analysis of CDR3 regions also showed a variability, although some VH and VL clones exhibited identical or nearly identical sequences. Thus, the B-cell infiltration observed in this breast medullary carcinoma does not reflect a monoclonal proliferation and represents an oligoclonal or a polyclonal B-cell proliferation.

A tumor specific single chain antibody dependent gene expression system

The design of conditional gene expression systems restricted to given tissues or cellular types is an important issue of gene therapy. Systems based on the targeting of molecules characteristic of the pathological state of tissues would be of interest. We have developed a synthetic transcription factor by fusing a single chain antibody (scFv) directed against p53 with the bacterial tetracycline repressor as a DNA binding domain. This hybrid protein binds to p53 and can interact with a synthetic promoter containing tetracycline-operator sequences. Gene expression can now be specifically achieved in tumor cells harboring an endogenous mutant p53 but not in a wild-type p53 containing tumor cell line or in a non-transformed cell line. Thus, a functional transactivator centered on single chain antibodies can be expressed intracellularly and induce gene expression in a scFv-mediated specific manner. This novel class of transcriptional transactivators could be referred as 'trabodies' for transcription-activating-antibodies. The trabodies technology could be useful to any cell type in which a disease related protein could be the target of specific antibodies.

Restoration of transcriptional activity of p53 mutants in human tumour cells by intracellular expression of anti-p53 single chain Fv fragments

We report here the production and the properties of single chain Fv fragments (scFvs) derived from the anti-p53 monoclonal antibodies PAb421 and 11D3. 11D3 is a newly generated monoclonal antibody which exhibits properties very comparable to those of PAb421. The scFvs PAb421 and 11D3 are able to stably associate with p53 and to restore the DNA binding activity of some p53 mutants in vitro. When expressed in p53 -/-human tumour cells, the scFv421 is essentially localized in the cytoplasm in the absence of p53, and in the nucleus when exogenous p53 is present. Thus, p53 is also able to stably associate with an anti-p53 scFv in cells. Cotransfection of p53 -/- human tumour cells with expression vectors encoding the His273 p53 mutant and either scFv leads to restoration of the p53 mutant deficient transcriptional activity. These data demonstrate that, in human tumour cells, these scFvs are able to restore a function essential for the tumour suppressor activity of p53 and may represent a novel class of molecules for p53-based cancer therapy.

Structurally different anthracyclines provoke different effects on cell cycle and tumor B cell differentiation

Previously we have detected a stimulatory effect on immunoglobulin (IgG) synthesis when hybridoma cells were treated with doxorubicin. In order to determine whether this is a general property of anthracycline, we have selected three analogs--doxorubicin (DOX), pirarubicin (THP-DOX) and aclarubicin (ACR)--which differ mainly in the methylation state of their amino sugars. Cell cycle analysis by flow cytometry and drug localization by scanning confocal microscopy were also performed. The results show that when cells (UN2 hybridoma B cells), were exposed to subtoxic doses of DOX or THP (with unmethylated amino sugars), a strong increases in IgG secretion, heavy (H) and light (L) chain synthesis and the corresponding mRNA levels were induced. Furthermore these two drugs arrested the cells in the G2/M phase of the cell cycle. In contrast, exposure to ACR (with its methylated amino sugar) at similar subtoxic doses induced a blockade of cells in the G1 phase with no increase of IgG synthesis, at the subtoxic doses used, all three drugs could still be detected in the nucleus as well as in the cytoplasm, as determined by confocal laser microscopy. Thus, the relationship between cell cycle blockade, IgG stimulation and anthracycline structure is suggested by these results.

A new set of monoclonal antibodies against human Fc gamma RII (CD32) and Fc gamma RIII (CD16): characterization and use in various assays

Four mouse anti-human Fc gamma RII (CD32) (6C4, 2B2, 3D3, 93.4) (IgG1, kappa) and one anti-human Fc gamma RIII (CD16) (7.5.4) IgG1, kappa) MAbs were raised. An in vitro switch variant, 7.5.4Sw50 (IgG2b, kappa), was also derived from the 7.5.4 MAb. 6C4, 2B2, and 3D3 MAbs bind both Fc gamma RIIa and Fc gamma RIIb isoforms. Two of them (6C4 and 2B2 MAbs) allow a complete blockade of the binding of immune complexes to Fc gamma RII. All three MAbs immunoprecipitate the receptor and bind both its glycosylated and nonglycosylated forms. The fourth anti Fc gamma RII MAb, 93.4, directed against the intracellular region of Fc gamma RIIa1/2, allows its detection by Western blotting only when it is not phosphorylated. The 7.5.4 MAb binds both Fc gamma RIIIa and Fc gamma RIIIb, can be used in Western blotting and does not inhibit aggregated IgG binding. ELISA using IV.3 (anti-Fc gamma RIIa1/2)/6C4 and 3G8 (anti-Fc gamma RIIIa/b)/7.5.4Sw50 MAb pairs make it possible to detect soluble Fc gamma RIIa1/2 and Fc gamma RIII, with a sensitivity of 200 pg/mL and 1 ng/mL, respectively. Surface plasmon resonance analyses indicated that the KD of two of the three anti-Fc gamma RII and of the anti-Fc gamma RIII are in the same order of magnitude (6C4: 0.78 nM, 2B2: 0.28 nM, 7.5.4: 0.47 nM). The anti-Fc gamma RII 3D3 MAb exhibits an off-rate constant higher than the 6C4 and 2B2 MAbs and a KD of 2.19 nM.

Production and characterization of mouse monoclonal antibodies to wild-type and oncogenic FLI-1 proteins

Mouse monoclonal antibodies were raised against the C-terminal domain of human FLI-1, a member of the ETS family of transcription factors which is involved in various murine and human malignancies. This FLI-1 specific domain is included in the fusion product EWS-FLI-1, an oncogenic variant of FLI-1 expressed in Ewing tumors. Antibodies were screened first by enzyme-linked immunosorbent assay onto recombinant FLI-1-coated plates. Positive clones were then tested for their ability to immunoprecipitate over-expressed EWS-FLI-1 protein. Three monoclonal antibodies were selected and further characterized. One of them, termed 7.3 MoAb, was shown to react with FLI-1 and EWS-FLI-1 in immunoblotting, immunoprecipitation, and immunofluorescence experiments. With all three methods, this antibody not only enabled the detection of overexpressed proteins but also more interestingly, that of endogenously expressed proteins. Furthermore, the 7.3 MoAb can specifically inhibit the interaction of FLI-1 with its DNA-binding site as shown by electrophoretic mobility shift assay. The 7.3 MoAb appears to be specific for FLI-1 because it does not react with ERG, the ETS family member most closely related to FLI-1. This antibody should be a useful tool in the diagnostic evaluation of Ewing tumors and should permit biochemical analyses to study the function of the wild-type FLI-1 protein and of the EWS-FLI-1 fusion protein.