RESUMO
Although luminal-type primary breast cancer can be efficiently treated, development of metastatic disease remains a significant clinical problem. We have previously shown that luminal-type circulating tumor cells (CTCs) co-expressing the tyrosine-kinase MET and CD47, a ligand involved in cancer cell evasion from macrophage scavenging, are able to initiate metastasis in xenografts. Here, we investigated the clinical relevance of MET-CD47 co-expression in 255 hormone receptor positive breast tumors by immunohistochemistry and found a 10.3- year mean overall-survival difference between MET-CD47 double-positive and double-negative patients (p<0.001) MET-CD47 co-expression defined a novel independent prognosticator for overall-survival by multivariate analysis (Cox proportional hazards model: HR: 4.1, p<0.002) and CD47 expression alone or in combination with MET was strongly associated with lymph node metastasis. Furthermore, flow cytometric analysis of metastatic patient blood revealed consistent presence of MET+CD47+ CTCs (range 0.8 - 33.3% of CTCs) and their frequency was associated with increased metastatic spread. Finally, primary uncultured CTCs with high MET+CD47+ content showed an enhanced capacity to initiate metastasis in mice. Detection and targeting of MET and CD47 may thus provide a rational basis for risk stratification and treatment of patients with luminal-type breast cancer.
Assuntos
Biomarcadores Tumorais/análise , Neoplasias da Mama/metabolismo , Antígeno CD47/análise , Carcinoma/metabolismo , Células Neoplásicas Circulantes/metabolismo , Proteínas Proto-Oncogênicas c-met/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Carcinoma/mortalidade , Carcinoma/secundário , Carcinoma/terapia , Feminino , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Pessoa de Meia-Idade , Análise Multivariada , Células Neoplásicas Circulantes/patologia , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
It has been hypothesized that carcinoma metastasis is initiated by a subpopulation of circulating tumor cells (CTCs) found in the blood of patients. However, although the presence of CTCs is an indicator of poor prognosis in several carcinoma entities, the existence and phenotype of metastasis-initiating cells (MICs) among CTCs has not been experimentally demonstrated. Here we developed a xenograft assay and used it to show that primary human luminal breast cancer CTCs contain MICs that give rise to bone, lung and liver metastases in mice. These MIC-containing CTC populations expressed EPCAM, CD44, CD47 and MET. In a small cohort of patients with metastases, the number of EPCAM(+)CD44(+)CD47(+)MET(+) CTCs, but not of bulk EPCAM(+) CTCs, correlated with lower overall survival and increased number of metastasic sites. These data describe functional circulating MICs and associated markers, which may aid the design of better tools to diagnose and treat metastatic breast cancer.
Assuntos
Neoplasias da Mama/sangue , Neoplasias da Mama/patologia , Metástase Neoplásica/patologia , Células Neoplásicas Circulantes/patologia , Adulto , Idoso , Animais , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Contagem de Células , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Pessoa de Meia-Idade , Metástase Neoplásica/genética , Prognóstico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: The use of circulating tumor cells (CTC) as a prognostic marker in metastatic breast cancer (MBC) has been well established. However, their efficacy and accuracy are still under scrutiny mainly because of methods of their enrichment and identification. We hypothesized that circulating miRNAs can predict the CTC status of patients with MBC, and tested for the same. Furthermore, we aimed at establishing a panel of circulating miRNAs capable of differentiating MBC cases from healthy controls. EXPERIMENTAL DESIGN: Circulating miRNAs from plasma of CTC-positive and CTC-negative patients with MBC, and healthy controls, were profiled by TaqMan Human MicroRNA arrays. Candidates from the initial screen were validated in an extended cohort of 269 individuals (61 CTC-positive, 72 CTC-negative, 60 CTC-low MBC cases, and 76 controls). RESULTS: CTC-positive had significantly higher levels of miR-141, miR-200a, miR-200b, miR-200c, miR-203, miR-210, miR-375, and miR-801 than CTC-negative MBC and controls (P < 0.00001), whereas miR-768-3p was present in lower amounts in MBC cases (P < 0.05). miR-200b was singled out as the best marker for distinguishing CTC-positive from CTC-negative patients (AUC 0.88). We identified combinations of miRNAs for differentiating MBC cases from controls (AUC 0.95 for CTC-positive; AUC 0.78 for CTC-negative). Combinations of miRNAs and miR-200b alone were found to be promising prognostic marker for progression-free and overall survival. CONCLUSION: This is the first study to document the capacity of circulating miRNAs to indicate CTC status and their potential as prognostic markers in patients with MBC.