title: Genomic profiling of mitochondrion-rich breast carcinoma: chromosomal changes may be relevant for mitochondria accumulation and tumour biology.
abstract: Oncocytic carcinomas are composed of mitochondrion-rich cells. Though recognised by the WHO classification as a histological special type of breast cancer, their status as a discrete pathological entity remains a matter of contention. Given that oncocytic tumours of other anatomical sites display distinct clinico-pathological and molecular features, we sought to define the molecular genetic features of mitochondrion-rich breast tumours and to compare them with a series of histological grade- and oestrogen receptor status-matched invasive ductal carcinomas of no special type. Seventeen mitochondrion-rich breast carcinomas, including nine bona fide oncocytic carcinomas, were profiled with antibodies against oestrogen, progesterone and androgen receptors, HER2, Ki67, GCDFP-15, chromogranin, epithelial membrane antigen, cytokeratin 7, cytokeratin 14, CD68 and mitochondria antigen. These tumours were microdissected and DNA extracted from samples with >70% of tumour cells. Fourteen cases yielded DNA of sufficient quality/quantity and were subjected to high-resolution microarray comparative genomic hybridisation analysis. The genomic profiles were compared to those of 28 grade- and oestrogen receptor status-matched invasive ductal carcinomas of no special type. Oncocytic and other mitochondrion-rich tumours did not differ significantly between themselves. As a group, mitochondrion-rich carcinomas were immunophenotypically heterogenous. Recurrent copy number changes were similar to those described in unselected breast cancers. However, unsupervised and supervised analysis identified a subset of mitochondrion-rich cancers, which often displayed gains of 11q13.1-q13.2 and 19p13. Changes in the latter two chromosomal regions have been shown to be associated with oncocytic tumours of the kidney and thyroid, respectively, and host several nuclear genes with specific mitochondrial function. Our results indicate that in a way akin to oncocytic tumours of other anatomical sites, at least a subset of mitochondrion-rich breast carcinomas may be underpinned by a distinct pattern of chromosomal changes potentially relevant for mitochondria accumulation and constitute a discrete molecular entity.
authors.affiliation: The Breakthrough Breast Cancer Research Centre, ICR, 237 Fulham Road, London SW3 6JB, UK.
authors.forename: Felipe C
authors.initials: FC
authors.lastname: Geyer
authors.forename: Dario
authors.initials: D
authors.lastname: de Biase
authors.forename: Maryou B K
authors.initials: MB
authors.lastname: Lambros
authors.forename: Moira
authors.initials: M
authors.lastname: Ragazzi
authors.forename: Maria A
authors.initials: MA
authors.lastname: Lopez-Garcia
authors.forename: Rachael
authors.initials: R
authors.lastname: Natrajan
authors.forename: Alan
authors.initials: A
authors.lastname: Mackay
authors.forename: Ivana
authors.initials: I
authors.lastname: Kurelac
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gasparre
authors.forename: Alan
authors.initials: A
authors.lastname: Ashworth
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Eusebi
authors.forename: Jorge S
authors.initials: JS
authors.lastname: Reis-Filho
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tallini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002869:Chromosome Aberrations; D002877:Chromosomes, Human / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D055028:Comparative Genomic Hybridization; D005260:Female; D006801:Humans; D008875:Middle Aged; D008928:Mitochondria / Q000473:pathology*; D024101:Mitochondrial Proteins / Q000235:genetics; D060787:Neoplasm Grading; D010641:Phenotype; D011960:Receptors, Estrogen / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; D011960:Receptors, Estrogen