Unknown,Transcriptomics,Genomics,Proteomics

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Polarity gene alterations in pure invasive micropapillary carcinomas of the breast

ABSTRACT: In this study we have identified a new morphological pattern in IMPC defined by the presence of numerous bi-nucleated cells, related to abnormal expression of genes involved in regulation of mitosis. We also demonstrated that IMPC presented tight and adherens junctions proteins expression modifications that could participate to their clinical behavior. We showed that IMPC was associated with a specific genomic profile compared to ER+ grade-matched IDC consisting of gains of 17q, high rates of 17q23 and 17q12 ERBB2 amplifications, losses of heterozygosity of 6q. The putative role of the genes located in this 6q LOH should be further investigated in order to determine if they could play a role in the presence of numerous bi-nucleated cells and inverted polarity of IMPC cells. In addition, we identified two genomic IMPC subsets: the first characterized by numerous amplicons with frequently near-tetraploid cells and the second, associated with different complex gains and losses in addition to 8q gains and 16q losses, and predominantly composed of near-diploïd cells. The observation of two genomic subsets within the IMPC entity suggests the existence of two possible oncogenic mechanisms leading to the development of a single disease. Phenotypical analysis was combined with copy number, genotyping (SNP6.0 Affymetrix) and transcriptomic analyses in a series of 39 pure IMPC. The results were compared to those of 27 ER and grade-matched invasive ductal carcinomas (IDC).

ORGANISM(S): Homo sapiens

SUBMITTER: Jaydutt Bhalshankar

PROVIDER: E-GEOD-37035 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Tumorigenic processes are understood to be driven by epi-/genetic and genomic alterations from single point mutations to chromosomal alterations such as insertions and deletions of nucleotides up to gains and losses of large chromosomal fragments including products of chromosomal rearrangements e.g. fusion genes and proteins. Overall comparisons of copy number alterations (CNAs) present in 48 clear cell renal cell carcinoma (ccRCC) genomes result in ratios of gene losses versus gene gains between 26 ccRCC Fuhrman malignancy grades G1 (ratio 1.25) and 20 G3 (ratio 0.58). Gene losses and gains of 15762 CNA genes are mapped to 795 chromosomal cytoband loci including 280 KEGG pathways. CNAs are classified according to their contribution to Fuhrman tumour gradings G1 and G3. Gene gains and losses turn out to be highly structured processes in ccRCC genomes enabling the subclassification and stratification of ccRCC tumours in a genome-wide manner. CNAs of ccRCC seem to start with common tumour related gene losses flanked by CNAs specifying Fuhrman grade G1 losses and CNA gains favouring grade G3 tumours. The appearance of recurrent CNA signatures implies the presence of causal mechanisms most likely implicated in the pathogenesis and disease-outcome of ccRCC tumours distinguishing lower from higher malignant tumours. Finally, the diagnostic quality of initial 201 genes (108 genes supporting G1 and 93 genes G3 phenotypes) are successfully validated on published Swiss data (GSE19949) leading to a restricted CNA gene set of 171 CNA genes of which 85 genes favour Fuhrman grade G1 and 86 genes Fuhrman grade G3. Regarding these gene sets overall survival decreases with the number of G3 related gene losses plus the total number of gene gains. CNA gene sets presented define an entry to a gene-directed and pathway-related functional understanding of ongoing copy number alterations within and between individual ccRCC tumours leading to CNA genes of prognostic and predictive value.

Project description:Ependymoma (EPN) posterior fossa group A (PFA) has the highest rate of recurrence and the worst prognosis of all EPN types. At relapse, it is typically incurable even with re-resection and re-irradiation. The biology of recurrent PFA EPN remains largely unknown, which hinders clinical advances. In this large longitudinal multicenter study, we examined matched samples of primary and recurrent disease from PFA EPN patients (n=95) to investigate the biology of recurrence. DNA methylomic data was used to measure copy number variants (CNVs), revealing progressive large scale chromosome gains and losses in successive recurrences. These CNV changes were dominated by chromosome 1q gain and/or 6q loss (1q+/6q-), both previously identified as high-risk factors in PFA EPN, which were present in ~20% at presentation but increased to ~60% at 1st recurrence. These CNV changes were correlated with hypomethylation of heterochromatin associated DNA at presentation. Evolution of chromosomal aberrations was further explored using CNV analysis of single-nuclei RNAseq on approximately 46,000 PFA EPN cells from 6 matched pairs of primary and 1st relapse tumors that harbored CNV changes at recurrence. No evidence of rare subclones in primary tumors was observed, suggesting that chromosomal rearrangement events occur after initial presentation. Cellular and molecular characteristics associated with CNVs were examined by single-nuclei RNAseq, bulk transcriptomic analysis and immunohistochemistry, revealing that 1q+/6q- PFA have a significantly higher mitotic index, increased proportions of proliferative epithelial progenitors and decreased differentiated neoplastic subpopulations. Multivariate survival analyses showed that cases with 1q gain or 6q loss at 1st recurrence were significantly more likely to recur than cases with no 1q or 6q change. The high prevalence of 1q+/6q- at recurrence and the associated shortened survival, suggest that both these abnormalities should be routinely tested for, and used for trial stratification.

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Polarity gene alterations in pure invasive micropapillary carcinomas of the breast

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