Biomedical subjects

François Bertucci

Publications and source records attributed to François Bertucci.

At least 19 recordsLinked to original sources

PubMed2006

FGFR1 and WT1 are markers of human prostate cancer progression.

BACKGROUND: Androgen-independent prostate adenocarcinomas are responsible for about 6% of overall cancer deaths in men. METHODS: We used DNA microarrays to identify genes related to the transition between androgen-dependent and androgen-independent stages in the LuCaP 23.1 xenograft model of prostate adenocarcinoma. The expression of the proteins encoded by these genes was then assessed by immunohistochemistry on tissue microarrays (TMA) including human prostate carcinoma samples issued from 85 patients who had undergone radical prostatectomy. RESULTS: FGFR1, TACC1 and WT1 gene expression levels were associated with the androgen-independent stage in xenografts and human prostate carcinoma samples. MART1 protein expression was correlated with pT2 tumor stages. CONCLUSION: Our results suggest that each of these four genes may play a role, or at least reflect a stage of prostate carcinoma growth/development/progression.

Adenocarcinoma↗

PubMed2006

Prognosis and gene expression profiling of 20q13-amplified breast cancers.

PURPOSE: Amplification of chromosomal region 20q13 occurs in breast cancer but remains poorly characterized. EXPERIMENTAL DESIGN: To establish the frequency of 20q13 amplification and select the amplified cases to be studied, we used fluorescence in situ hybridization of bacterial artificial chromosome probes for three 20q13 loci (MYBL2, STK6, ZNF217) on sections of tissue microarrays containing 466 primary carcinoma samples. We used Affymetryx whole-genome DNA microarrays to establish the gene expression profiles of 20q13-amplified tumors and quantitative reverse transcription-PCR to validate the results. RESULTS: We found 36 (8%) 20q13-amplified samples. They were distributed in two types: type 1 tumors showed ZNF217 amplification only, whereas type 2 tumors showed amplification at two or three loci. Examination of the histoclinical features of the amplified tumors showed two strikingly opposite data. First, type 1 tumors were more frequently lymph node-negative tumors but were paradoxically associated with a poor prognosis. Second, type 2 tumors were more frequently lymph node-positive tumors but were paradoxically associated with a good prognosis. Type 1 and type 2 showed different gene expression profiles. No 20q13 gene could be associated with type 1 amplification, whereas several 20q13 genes were overexpressed in type 2 tumors. CONCLUSIONS: Our results suggest that amplified tumors of types 1 and 2 are two distinct entities resulting from two different mechanisms and associated to different prognosis.

Breast Neoplasms↗

PubMed2006

Proteomics of breast cancer: principles and potential clinical applications.

Progresses in screening, early diagnosis, prediction of aggressiveness and of therapeutic response or toxicity, and identification of new targets for therapeutic will improve survival of breast cancer. These progresses will likely be accelerated by the new proteomic techniques. In this review, we describe the different techniques currently applied to clinical samples of breast cancer and the most important results obtained with the two most popular proteomic approaches in translational research (tissue microarrays and SELDI-TOF).

Breast Neoplasms↗

PubMed2006

Gene expression profiling shows medullary breast cancer is a subgroup of basal breast cancers.

Medullary breast cancer (MBC) is a rare but enigmatic pathologic type of breast cancer. Despite features of aggressiveness, MBC is associated with a favorable prognosis. Morphologic diagnosis remains difficult in many cases. Very little is known about the molecular alterations involved in MBC. Notably, it is not clear whether MBC and ductal breast cancer (DBC) represent molecularly distinct entities and what genes/proteins might account for their differences. Using whole-genome oligonucleotide microarrays, we compared gene expression profiles of 22 MBCs and 44 grade III DBCs. We show that MBCs are less heterogeneous than DBCs. Whereas different molecular subtypes (luminal A, luminal B, basal, ERBB2-overexpressing, and normal-like) exist in DBCs, 95% MBCs display a basal profile, similar to that of basal DBCs. Supervised analysis identified gene expression signatures that discriminated MBCs from DBCs. Discriminator genes are associated with various cellular processes related to MBC features, in particular immune reaction and apoptosis. As compared with MBCs, basal DBCs overexpress genes involved in smooth muscle cell differentiation, suggesting that MBCs are a distinct subgroup of basal breast cancer with limited myoepithelial differentiation. Finally, MBCs overexpress a series of genes located on the 12p13 and 6p21 chromosomal regions known to contain pluripotency genes. Our results contribute to a better understanding of MBC and of mammary oncogenesis in general.

Adult↗

PubMed2006

[Genetic factors and colorectal cancers development: therapeutic impact].

Colorectal tumorigenesis is associated with the progressive increase of epithelium dysplasia and wall invasion. These criteria are evaluated through histological staging, that enables a reliable estimation of patient prognosis, and is the best tool for therapeutic decision. Adjuvant chemotherapy is systematically proposed in case of lymph nodes and/or distant metastases (stages III and IV respectively). Its benefit in stage II tumors however remains unclear. Independently of the nature of the treatment, one third of all stage II-III tumors will metastasize. One important element to improve our tools for therapeutic decision is the identification of prognostic parameters, independent of the histological and morphological classifications. In a preliminary study, we allelotyped a series of 401 colon tumors and have shown that 5q and 8p allelic status were significantly predictive of the patients evolution. As a first approach, analysis of 47 tumors using microarray expression measures has allowed to validate the strong correlation between RNA levels and genomic status (i.e. mutation and allelic status) of known genes (APC, SMAD4, TP53, MLH1). We are now planning to characterize a series of 185 stage II-III colon tumors at both genomic and transcriptomic levels, in combination with the clinicopathological findings. Disease-free patients were followed at least 3 years after surgical resection. A tight collaboration of 5 departments of digestive oncology allowed to collect all clinical and biological resources for this project. Depending on our findings, correlations will be made between gene expression levels and somatic mutations of the coreesponding genes. Real time RT-PCR and immunohistochemical analyses will be performed on selected genes. Finally, biological mechanisms will be investigated to look for new therapeutic targets.

Colorectal Neoplasms↗

PubMed2006

Gene expression profiling and clinical outcome in breast cancer.

Pathologic and clinical heterogeneity of breast cancer reflects the poorly documented, complex, and combinatory molecular basis of the disease and is in part responsible for therapeutic failures. The DNA microarray technique allows the analysis of RNA expression of several thousands of genes simultaneously in a sample. There are multiple potential applications of the technique in cancer research. A number of recent studies have shown the promising role of gene expression profiling in breast cancer by identifying new prognostic subclasses unidentifiable by conventional parameters and new prognostic and/or predictive gene signatures, whose predictive impact is superior to conventional histoclinical prognostic factors. In this review we describe current use of DNA microarrays in the prognosis of breast cancer. We also discuss issues that need to be addressed in the near future to allow the method to reach its full potential.

Breast Neoplasms↗

PubMed2006

Acquired resistance to imatinib and secondary KIT exon 13 mutation in gastrointestinal stromal tumour.

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract. Most of them have an activating mutation of KIT or PDGFRalpha tyrosine-kinase receptors. Imatinib is a selective tyrosine-kinase inhibitor of ABL, KIT and PDGFR, and provides a clinical benefit in about 85% of patients with advanced GIST. Unfortunately, secondary resistance following initial responses occurs in most of the cases, and molecular mechanisms are poorly understood. We sequenced KIT and PGDFRalpha exons from one patient with GIST before and after the development of imatinib resistance. We identified, in addition to a primary mutation in exon 9, a secondary mutation in KIT exon 13 (first kinase domain) in the resistant sample. We demonstrate for the first time the feasibility of sequencing such samples removed by non-surgical biopsies during imatinib therapy. Such a approach, far less invasive than surgery and combined with sequencing, will likely help in better tailoring the treatment of advanced GISTs and understanding the mechanisms of resistance and response to imatinib.

Antineoplastic Agents↗

PubMed2005

Gene expression profiling identifies molecular subtypes of inflammatory breast cancer.

Breast cancer is a heterogeneous disease. Comprehensive gene expression profiles obtained using DNA microarrays have revealed previously indistinguishable subtypes of noninflammatory breast cancer (NIBC) related to different features of mammary epithelial biology and significantly associated with survival. Inflammatory breast cancer (IBC) is a rare, particular, and aggressive form of disease. Here we have investigated whether the five molecular subtypes described for NIBC (luminal A and B, basal, ERBB2 overexpressing, and normal breast-like) were also present in IBC. We monitored the RNA expression of approximately 8,000 genes in 83 breast tissue samples including 37 IBC, 44 NIBC, and 2 normal breast samples. Hierarchical clustering identified the five subtypes of breast cancer in both NIBC and IBC samples. These subtypes were highly similar to those defined in previous studies and associated with similar histoclinical features. The robustness of this classification was confirmed by the use of both alternative gene set and analysis method, and the results were corroborated at the protein level. Furthermore, we show that the differences in gene expression between NIBC and IBC and between IBC with and without pathologic complete response that we have recently reported persist in each subtype. Our results show that the expression signatures defining molecular subtypes of NIBC are also present in IBC. Obtained using different patient series and different microarray platforms, they reinforce confidence in the expression-based molecular taxonomy but also give evidence for its universality in breast cancer, independently of a specific clinical form.

Adenocarcinoma↗

PubMed2005

Protein expression profiling identifies subclasses of breast cancer and predicts prognosis.

Breast cancer is a heterogeneous disease whose evolution is difficult to predict by using classic histoclinical prognostic factors. Prognostic classification can benefit from molecular analyses such as large-scale expression profiling. Using immunohistochemistry on tissue microarrays, we have monitored the expression of 26 selected proteins in more than 1,600 cancer samples from 552 consecutive patients with early breast cancer. Both an unsupervised approach and a new supervised method were used to analyze these profiles. Hierarchical clustering identified relevant clusters of coexpressed proteins and clusters of tumors. We delineated protein clusters associated with the estrogen receptor and with proliferation. Tumor clusters correlated with several histoclinical features of samples, including 5-year metastasis-free survival (MFS), and with the recently proposed pathophysiologic taxonomy of disease. The supervised method identified a set of 21 proteins whose combined expression significantly correlated to MFS in a learning set of 368 patients (P < 0.0001) and in a validation set of 184 patients (P < 0.0001). Among the 552 patients, the 5-year MFS was 90% for patients classified in the "good-prognosis class" and 61% for those classified in the "poor-prognosis class" (P < 0.0001). This difference remained significant when the molecular grouping was applied according to lymph node or estrogen receptor status, as well as the type of adjuvant systemic therapy. In multivariate analysis, the 21-protein set was the strongest independent predictor of clinical outcome. These results show that protein expression profiling may be a clinically useful approach to assess breast cancer heterogeneity and prognosis in stage I, II, or III disease.

Adult↗

PubMed2005

Comprehensive profiling of 8p11-12 amplification in breast cancer.

In human carcinomas, especially breast cancer, chromosome arm 8p is frequently involved in complex chromosomal rearrangements that combine amplification at 8p11-12, break in the 8p12-21 region, and loss of 8p21-ter. Several studies have identified putative oncogenes in the 8p11-12 amplicon. However, discrepancies and the lack of knowledge on the structure of this amplification lead us to think that the actual identity of the oncogenes is not definitively established. We present here a comprehensive study combining genomic, expression, and chromosome break analyses of the 8p11-12 region in breast cell lines and primary breast tumors. We show the existence of four amplicons at 8p11-12 using array comparative genomic hybridization. Gene expression analysis of 123 samples using DNA microarrays identified 14 genes significantly overexpressed in relation to amplification. Using fluorescence in situ hybridization analysis on tissue microarrays, we show the existence of a cluster of breakpoints spanning a region just telomeric to and associated with the amplification. Finally, we show that 8p11-12 amplification has a pejorative effect on survival in breast cancer.

Breast Neoplasms↗

PubMed2005

Identification of TCL1A as an immunohistochemical marker of adverse outcome in diffuse large B-cell lymphomas.

We used a combination of DNA-microarray and tissue-microarray (TMA) analyses to identify markers that could be routinely used to predict the outcome of diffuse large-B-cell lymphoma (DLCL) patients. Gene expression profiling was performed using DNA-microarrays on 52 tumour biopsy samples [31 DLCL and 21 follicular lymphomas (FL)] from 48 patients (28 DLCL and 20 FL). T-cell leukemia/lymphoma-1A (TCL1A) mRNA overexpression was correlated with relapse in DLCL patients. TMA analysis was applied on a distinct series of 36 formalin-fixed, paraffin-embedded DLCL samples and showed that TCL1A immunoexpression was correlated with either higher relapse (p=0.02) or lower 5-year overall survival (p=0.009) rates. Moreover, the prognostic value of TCL1A was independent from IPI in our series. Our data suggest that TCL1A immunodetection is an independent marker of adverse outcome that could be used in routine settings for the management of DLCL patients.

Adult↗

PubMed2005

How to best classify breast cancer: conventional and novel classifications (review).

Breast cancer is a complex disease and different classifications, mostly based on clinical and pathological features, have been used for guiding the management of patients. Most of them fail to reflect breast cancer heterogeneity, which could be the reason why the treatment fails in approximately 30% of cases. Emerging molecular studies based on gene expression profiling using DNA microarrays have defined new molecular subtypes of breast cancer associated with the cell-of-origin distinction. Thus, breast cancer has been divided into five subgroups with distinct biological features and clinical outcomes. We have tried here to confront the conventional existing classifications with this new molecular taxonomy. It is likely that using all types of classification together will help in the management of breast cancer.

Breast Neoplasms↗

PubMed2004

Identification of new classes among acute myelogenous leukaemias with normal karyotype using gene expression profiling.

Conventional cytogenetic analysis currently stratifies acute myelogenous leukaemia (AML) into prognostically relevant groups. However, approximately 50% of adult AMLs have normal cytogenetics (NC-AMLs), and represent a heterogeneous and poorly understood group. We analysed gene expression in 55 AML samples including 53 cases from adult patients with NC-AML (n = 36), trisomy 8, t(15;17), t(8;21), t(11;19), 7q deletion, and two cell lines using 9000-gene DNA microarrays. Global hierarchical clustering showed that NC-AMLs are a heterogeneous group. Supervised analysis distinguished two subgroups of NC-AML: one subgroup constituted a homogeneous NC cluster ('pure NC-AML'), and the other NC-AMLs were close to the AML cases with translocations ('translocation like'). Gene expression signatures were also derived for patients with trisomy 8, as well as FLT3 and MLL gene duplications. Importantly, samples from 24 NC-AML patients who could be evaluated for clinical outcome were analysed. In all, 43 genes that discriminated two classes of patients with significantly different prognosis were identified. The poor prognosis class contained a majority of 'pure NC-AMLs', whereas the 'translocation-like' AMLs were in the good prognosis class. Discriminator genes included genes involved in drug resistance (TOP2B), protein transport (MTX2, SLC35A2), and cell signalling (MAPK1, PRKAB2). Our results demonstrate the transcriptional heterogeneity of NC-AMLs, and suggest the existence of 'translocation-like' NC-AMLs and of a gene expression signature that may predict response to chemotherapy.

DNA-Binding Proteins↗

PubMed2004

Gene expression profiling for molecular characterization of inflammatory breast cancer and prediction of response to chemotherapy.

Inflammatory breast cancer (IBC) is a rare but aggressive form of breast cancer with a 5-year survival limited to approximately 40%. Diagnosis, based on clinical and/or pathological criteria, may be difficult. Optimal systemic neoadjuvant therapy and accurate predictors of pathological response have yet to be defined for increasing response rate and survival. Using DNA microarrrays containing approximately 8,000 genes, we profiled breast cancer samples from 81 patients, including 37 with IBC and 44 with noninflammatory breast cancer (NIBC). Global unsupervised hierarchical clustering was able to some extent to distinguish IBC and NIBC cases and revealed subclasses of IBC. Supervised analysis identified a 109-gene set the expression of which discriminated IBC from NIBC samples. This molecular signature was validated in an independent series of 26 samples, with an overall performance accuracy of 85%. Discriminator genes were associated with various cellular processes possibly related to the aggressiveness of IBC, including signal transduction, cell motility, adhesion, and angiogenesis. A similar approach, with leave-one-out cross-validation, identified an 85-gene set that divided IBC patients with significantly different pathological complete response rate (70% in one group and 0% in the other group). These results show the potential of gene expression profiling to contribute to a better understanding of IBC, and to provide new diagnostic and predictive factors for IBC, as well as for potential therapeutic targets.

Adult↗

PubMed2004

[Therapeutic implications of advances in breast cancer biology].

The polygenic and multifactor genetic basis of breast cancer confers to each tumour a different phenotype and clinical outcome. A therapeutic stake is to better determine this heterogeneity by using more reliable prognostic factors and to develop molecular therapies targeting the tumour cells selectively. The study of molecular alterations in breast cancer allowed considerable therapeutic progress by use of the hormonal receptors and the ERBB2 receptor. Today, new high-throughput technologies such as DNA microarrays allow measuring the activity of thousands of genes in a sample simultaneously. The awaited repercussions are multiple. Expression profiling of breast tumours allows the identification of new sub-groups of tumour in groups a priori identical, but with different outcome. This stratification should make it possible to better tailor the treatment and boost the discovery of new therapeutic targets

Antineoplastic Agents, Hormonal↗

PubMed2004

Identification and validation of an ERBB2 gene expression signature in breast cancers.

ERBB2 is a transmembrane tyrosine kinase receptor encoded by a gene located in chromosome region 17q12. Overexpression of ERBB2, generally by way of gene amplification, plays a role in mammary oncogenesis. This alteration can be overcome by use of the humanized monoclonal antibody trastuzumab (Herceptin). Accurate determination of ERBB2 status is required for appropriate use of this targeted therapy and is currently analysed by immunohistochemistry (IHC) on tissue sections and/or fluorescence in situ hybridisation (FISH) on interphase chromosomes. We have studied the gene expression profiles of a series of 213 breast tumours and 16 breast cancer cell lines with known ERBB2 status, using Ipsogen's DiscoveryChip microarrays with approximately 9000 cDNAs. We have identified 36 genes and expressed sequence tags that were differentially expressed in tumours and in cell lines with and without ERBB2 protein overexpression. This ERBB2-specific gene expression signature (GES) contained 29 overexpressed genes including the ERBB2 gene itself, five genes located in its immediate vicinity on 17q12, non-17q genes such as GATA4 and eight downregulated genes including oestrogen receptor alpha (ER). Some correlations were validated at the protein level using IHC on tissue microarrays. The GES was able to distinguish ERBB2-negative and -positive cancer samples, as well as FISH-negative and FISH-positive ERBB2 2+ IHC samples.

Adult↗

PubMed2004

Gene expression profiling of colon cancer by DNA microarrays and correlation with histoclinical parameters.

Different diagnostic and prognostic groups of colorectal carcinoma (CRC) have been defined. However, accurate diagnosis and prediction of survival are sometimes difficult. Gene expression profiling might improve these classifications and bring new insights into underlying molecular mechanisms. We profiled 50 cancerous and noncancerous colon tissues using DNA microarrrays consisting of approximately 8000 spotted human cDNA. Global hierarchical clustering was to some extent able to distinguish clinically relevant subgroups, normal versus cancer tissues and metastatic versus nonmetastatic tumours. Supervised analyses improved these segregations by identifying sets of genes that discriminated between normal and tumour tissues, tumours associated or not with lymph node invasion or genetic instability, and tumours from the right or left colon. A similar approach identified a gene set that divided patients with significantly different 5-year survival (100% in one group and 40% in the other group; P=0.005). Discriminator genes were associated with various cellular processes. An immunohistochemical study on 382 tumour and normal samples deposited onto a tissue microarray subsequently validated the upregulation of NM23 in CRC and a downregulation in poor prognosis tumours. These results suggest that microarrays may provide means to improve the classification of CRC, provide new potential targets against carcinogenesis and new diagnostic and/or prognostic markers and therapeutic targets.

Colon↗

PubMed2004

Immunophenotypic analysis of inflammatory breast cancers: identification of an 'inflammatory signature'.

Inflammatory breast cancer (IBC) is a rare but very aggressive form of breast cancer. Its definition is based on clinical criteria, but a molecular definition could be useful when data are incomplete or features are missing. Recently, the identification of overexpression of E-cadherin in IBC has improved understanding of the molecular basis of this disease. Consequently, the aim of this study was to try to determine an immunophenotypic 'signature' of IBC. A series of 80 cases of IBC were compared with 552 non-IBC control cases and a model was elaborated to evaluate the probability of an inflammatory carcinoma being present in any clinical situation. Tissue microarrays (TMAs) were used to determine the immunohistochemical profile of eight proteins including E-cadherin, EGFR, oestrogen and progesterone receptor (ER and PR), MIB1, ERBB2, MUC1, and P53. All the parameters tested were differentially expressed between IBC and control cases in univariate analysis (p < 0.001). The five variables that were significantly associated with IBC in multivariate analysis were E-cadherin > or = 300 [HR = 5.64 (2.92-10.87)], ER negative [HR = 3.00 (1.67-5.51)], MIB1 > 20 [HR = 3.54 (1.87-6.71)], MUC1 cytoplasmic staining [HR = 2.72 (1.49-4.96)], and ERBB2 positive 2+ or 3+ [HR = 2.46 (1.26-4.78)]. The probability that a breast cancer with this full phenotype at diagnosis was an IBC was 90.5%. If any one of the five parameters was missing, this probability dropped to 75% and was less than 50% when one, two, or three parameters were present. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) of patients with IBC were not significantly different from those of the non-IBC control group that expressed four or five parameters (nIBC-1), but this nIBC-1 control group had a significantly worse outcome than the non-IBC control group (nIBC-2) with only 0-3 parameters (p = 0.0049 for OS and p < 0.0001 for DFS). In conclusion, an immunophenotypic signature was suggested for IBC. This could help to determine the worst cases, independent of clinical criteria.

Adult↗