RESUMO
Triple negative breast cancer (TNBC) is characterized by high proliferation, poor differentiation and a poor prognosis due to high rates of recurrence. Despite lower overall incidence African American (AA) patients suffer from higher breast cancer mortality in part due to the higher proportion of TNBC cases among AA patients compared to European Americans (EA). It was recently shown that the clinical heterogeneity of TNBC is reflected by distinct transcriptional programs with distinct drug response profiles in preclinical models. In this study, gene expression profiling and immunohistochemistry were used to elucidate potential differences between TNBC tumors of EA and AA patients on a molecular level. In a retrospective cohort of 136 TNBC patients, a major transcriptional signature of proliferation was found to be significantly upregulated in samples of AA ethnicity. Furthermore, transcriptional profiles of AA tumors showed differential activation of insulin-like growth factor 1 (IGF1) and a signature of BRCA1 deficiency in this cohort. Using signatures derived from the meta-analysis of TNBC gene expression carried out by Lehmann et al., tumors from AA patients were more likely of basal-like subtypes whereas transcriptional features of many EA samples corresponded to mesenchymal-like or luminal androgen receptor driven subtypes. These results were validated in The Cancer Genome Atlas mRNA and protein expression data, again showing enrichment of a basal-like phenotype in AA tumors and mesenchymal subtypes in EA tumors. In addition, increased expression of VEGF-activated genes together with elevated microvessel area determined by the AQUA method suggest that AA patients exhibit higher tumor vascularization. This study confirms the existence of distinct transcriptional programs in triple negative breast cancer in two separate cohorts and that these programs differ by racial group. Differences in TNBC subtypes and levels of tumor angiogenesis in AA versus EA patients suggest that targeted therapy choices should be considered in the context of race.
Assuntos
Neoplasias da Mama , Bases de Dados Genéticas , Regulação Neoplásica da Expressão Gênica , Proteínas de Neoplasias , Neovascularização Patológica , RNA Mensageiro , RNA Neoplásico , Adulto , Negro ou Afro-Americano , Idoso , Neoplasias da Mama/etnologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Neovascularização Patológica/etnologia , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Estudos RetrospectivosRESUMO
Breast cancer brain metastases are on the rise and their treatment is hampered by the limited entry and efficacy of anticancer drugs in this sanctuary. The sodium iodide symporter, NIS, actively transports iodide across the plasma membrane and is exploited clinically to deliver radioactive iodide into cells. As in thyroid cancers, NIS is expressed in many breast cancers including primary and metastatic tumors. In this study NIS expression was analyzed for the first time in 28 cases of breast cancer brain metastases using a polyclonal anti-NIS antibody directed against the terminal C-peptide of human NIS gene and immunohistochemical methods. Twenty-five tumors (84%) in this retrospective series were estrogen/progesterone receptor-negative and 15 (53.6%) were HER2+. Overall 21 (75%) cases and 80% of HER2 positive metastases were NIS positive. While the predominant pattern of NIS immunoreactivity is intracellular, plasma membrane immunopositivity was detected at least focally in 23.8% of NIS-positive samples. Altogether, these findings indicate that NIS expression is prevalent in breast cancer brain metastases and could have a therapeutic role via the delivery of radioactive iodide and selective ablation of tumor cells.
Assuntos
Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias da Mama/patologia , Simportadores/metabolismo , Feminino , Humanos , Receptores de Estrogênio , Receptores de Progesterona/genética , Estudos Retrospectivos , Simportadores/genéticaRESUMO
We report a novel chromosomal translocation in AML, t(X;21)(q25-26;q22), resulting in a fusion transcript between two ETS domain family members, ELF4 (at Xq25) and ERG (at 21q22). ERG has been associated previously with other fusion partners, specifically FUS and EWSR1, and implicated in both AML and Ewing's sarcoma. RT-PCR analysis of RNA isolated from bone marrow samples from the patient demonstrates that the translocation occurs within intron 1 of ERG isoform 1 (ERG-1) and intron 2 of ELF4 resulting in an in-frame fusion joining exon 2 from ELF4 with exon 2 of ERG. This is the first reported case of an ELF4-ERG fusion and identification of the specific ERG exon involved in the fusion that differentiates ERG isoforms. In addition, this case also directly implicates a new role for ELF4 in cancer.
