Project description:In a previous study of ductal carcinoma in situ (DCIS) of the breast (see GEO accession #GSE7882) we identified six genes at chromosome 17q21.33 that were over-expressed in high grade cases, and showed a correlation between expression level and gene copy number. The aim of this study was to determine whether potential drivers of high grade breast cancer growth could be identified at 17q21.33. High resolution comparative genomic hybridisation was used to interrogate genomic aberrations in laser capture microdissected samples of ductal carcinoma in situ.
Project description:Phenotypic and genomic characterization of Early Stage Breast Carcinoma using Training set (n=109) Validation set (n=105) of SNP6 arrays
Project description:Phenotypic and genomic characterization of Early Stage Breast Carcinoma using Training set (n=109) Validation set (n=105) of SNP6 arrays Affymetrix SNP6.0 arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved breast tumoral samples.
Project description:Genome profiling was compared between medullary breast carcinoma (MBC) and non medullary basal-like breast carcinoma (non-MBC BLC).
Project description:Genomic hallmarks of homologous recombination deficiency in invasive breast carcinomas to appear in Internationa Journal of Cancer Transcriptome analysis of 243 (plus 12 duplicates) primary breast invasive carcinoma samples of various molecular subtypes.
Project description:Abstract: Purpose: To identify a DNA signature to predict metastasis of small node-negative breast carcinoma Experimental Design: The authors used Comparative Genomic Hybridization (CGH) array to analyze 168 pT1T2pN0 invasive ductal carcinoma patients with either good (no event 5 years after diagnosis: 111 patients) or poor (57 patients with early onset metastasis) outcome. A CGH classifier, identifying low and high-risk groups of metastatic recurrence, was established in a training set of 78 patients. This classifier was based on both genomic regions with statistically different alterations between the two groups of clinical outcome and the number of alterations. It was then tested on a validation set of 90 patients and compared to clinicopathological parameters. Results: The genomic status of regions located on chromosomes 2p22.2, 3p23 and 8q21-24 and the number of segmental alterations were defined in the training set to classify tumors into low or high-risk groups. In the validation set, this CGH classifier produced a highly significant odds ratio of 10.39 (95%CI: 3.75-28.78, p=6.63×10-6, Wald test) in univariate analysis with a sensitivity of 66%, a specificity of 84% and an accuracy rate of 78%. The 5-year metastasis-free survival analysis showed a highly significant difference between the two predicted groups (Hazard Ratio=5.7, p=1.82×10-7, log-rank test). Together with estrogen receptor and grade, this CGH classifier provided significant prognostic information in multivariate analysis. Conclusions: In addition to classical parameters, this DNA signature may constitute an accurate tool to identify patients with T1T2N0 luminal tumors, who may benefit from adjuvant treatments.
Project description:Background The dramatic increase in incidence of ductal carcinoma in situ (DCIS) associated with mammographic screening for breast cancer has given emphasis to the challenges of managing this important clinical entity. Unlike invasive breast cancer, there is no established histopathologic grading system for DCIS, nor are there biological markers of prognosis to guide clinical management. The aim of this study is to use molecular profiling to identify robust and clinically applicable indicators of DCIS malignant potential. Methods Areas of intraduct carcinoma, atypical ductal hyperplasia and benign epithelium were isolated from 46 well-characterised invasive breast cancers by laser capture microdissection. Microarray based gene expression profiling was used to identify genes differentially expressed between DCIS associated with grade 1 and grade 3 invasive carcinoma (‘grade associated genes’). The expression profile of these genes was then determined in all samples and used to define ‘molecular grade’ categories. The genomic basis of gene expression derived categories was examined by array-based comparative genomic hybridisation (CGH). Results DCIS samples could be divided into two subgroups, designated low and high molecular grade (MG) on the basis of expression at 173 grade associated oligonucleotide probes. The low MG subgroup included 21 DCIS samples of low (n=10) and intermediate (n=11) nuclear grade as well as all samples of ADH (n=4) and benign epithelium (n=7). The high MG subgroup included 27 DCIS samples of intermediate (n=7) and high (n=19) nuclear grade. Array CGH revealed distinct differences in the character and degree of genomic aberration associated with MG and the clinical significance of MG was verified by a strong correlation with survival in two independent invasive breast cancer gene expression datasets (n=295 and n=186). MG categories were strongly associated with histopathologic and biomarker features of DCIS. Using a classification tree model, DCIS MG could be accurately predicted in 44/46 (95.7%) of samples using a combination of nuclear grade and Ki67 score. Conclusions Molecular profiling indicates a binary grading scheme for DCIS that is both biologically relevant and clinically informative. The low and high MG DCIS classification could be recapitulated by a novel combination of routinely accessible features. This practical approach has potential to immediately improve clinical evaluation and management of DCIS. Keywords: Paired gene expression and CGH Paired CGH and Gene Expression on DCIS of the breast