上皮间充质转化与肿瘤干细胞的研究进展

上皮细胞间充质转化(epithelial-mesenchymal transition, EMT) 在胚胎发育和肿瘤发生中具有重要作用, EMT可使上皮性肿瘤细胞获得间充质细胞表型, 在增强肿瘤细胞的侵袭和转移能力的同时, 也使得肿瘤细胞具有自我更新能力等干细胞样特性。多种转录因子、信号转导通路、microRNAs及细胞微环境等因素共同调控此过程。EMT与肿瘤干细胞之间有密不可分的联系, EMT可以促进肿瘤细胞获得干细胞特征, 具有干细胞特征的肿瘤细胞高表达EMT标记分子, microRNA可同时调控EMT和细胞干性。阐明EMT与肿瘤干细胞的相互关系及其调控机制, 有望为肿瘤转移与复发的靶向治疗开辟新思路。      

上皮-间质转化与乳腺癌

上皮-间质转化(EMT)使原发癌细胞获得间质特征,并且在转移部位上皮再生形成继发性肿瘤.该过程参与乳腺癌的浸润和转移,有可能影响疗效.乳腺癌细胞的一系列标记蛋白可监测转录调节和表观遗传调控引起的细胞学行为的特征性改变,并能够提供预测依据和治疗靶点.     

上皮间质转化与肿瘤干细胞

上皮-间质转化(EMT)是生物胚胎发育的基础过程,与肿瘤细胞的原位侵袭和远处转移也密切相关.EMT与肿瘤干细胞(CSC)关系密切.CSC有较强的自我更新和致瘤能力以及细胞分化潜能.通过对CSC标志物的鉴定,深入研究其耐药性,可为肿瘤治疗提供新径.     

Clinical significance of circulating tumor cells in breast cancer patients

Circulating tumor cells (CTCs) are defined as tumor cells circulating in the peripheral blood of patients, shed from either the primary tumors or its metastases. Many techniques have been developed in the recent years to identify CTCs in breast cancer patients, and trials have proved the prognostic significance of CTCs. In this study, we validated the CTC detection method of combining cell filtration and laser scanning cytometry (LSC), which was highly reproducible with increased sensitivity and accuracy. In 134 non-metastatic breast cancer patients analyzed, HER2 was found to be the only primary tumor characteristics that correlated with the presence of CTCs. 85 patients with definitive stage information were selected for association study between the disease stages and CTC numbers. The detection rate and the number of CTCs were correlated with the disease stages. Moreover, assessment of CTCs in 92 metastatic breast cancer patients was found to be able to predict the efficacy of chemotherapy. Increase in CTC numbers was an independent prognostic factor for treatment outcomes. Our results suggested that CTC assessment could be an indication of the disease progression and analysis of the properties of CTCs is likely to provide new insights into the biology of breast cancer and contribute to defining novel treatments and better prediction of clinical outcomes.     

循环肿瘤细胞及循环肿瘤DNA检测在乳腺癌中的研究进展

乳腺癌是中国女性最常见的癌症,其早期检测、个体化治疗及实时疾病监测一直是科研及临床工作者关注的重点。癌症患者血液中循环肿瘤细胞(CTC)和循环肿瘤DNA(ctDNA)的检测微创、简便,易实时获取信息。目前,有关CTC富集鉴定方法多种多样,CTC及ctDNA检测的敏感度和特异度较前有所提高,未来研究面临的最大挑战为肿瘤细胞特异性标志物的开发以及ctDNA临床意义的研究。CTC及ctDNA在基础研究、检测方法、CTC培养、早期肿瘤检测、个体化治疗及临床预后等方面的研究均有开展。笔者对乳腺癌CTC及ctDNA的研究进展作一总结。     

上皮细胞间质转化与肿瘤干细胞

Epithelial-mesenchymal transition (EMT) not only can endow cells migration and invasion characteristics, but also can make tumor cells obtain self-renewal ability and have the characteristics of stem cells, which might result in cancer stem cell (CSC). There are the same molecular mechanism and microenvironment between EMT and CSC, which have great clinic significances for the diagnosis and treatment of the aggressive cancers. Moreover, many studies show that miR-200 could regulate EMT and CSC, participate in the tumor invasion and metastasi, and promote the research of targeted cancer therapy.     

Expression of stem cell and epithelial-mesenchymal transition markers in primary breast cancer patients with circulating tumor cells

Introduction  

The presence of circulating tumor cells (CTC) in breast cancer might be associated with stem cell-like tumor cells which have been suggested to be the active source of metastatic spread in primary tumors. Furthermore, to be able to disseminate and metastasize, CTC must be able to perform epithelial-mesenchymal transition (EMT). We studied the expression of three EMT markers and the stem cell marker ALDH1 in CTC from 502 primary breast cancer patients. Data were correlated with the presence of disseminated tumor cells (DTC) in the bone marrow (BM) and with clinicopathological data of the patients.     

Recent translational research: circulating tumor cells in breast cancer patients

In breast cancer patients, hematogenous tumor cell dissemination can be detected, even at the single cell level, by applying immunocytochemical and molecular assays. Various methods for the detection of circulating tumor cells in the peripheral blood have been described. Results from recently reported studies suggest that circulating tumor cell levels may serve as a prognostic marker and for the early assessment of therapeutic response in patients with metastatic breast cancer. However, in early-stage breast cancer, the impact of circulating tumor cells is less well established than the presence of disseminated tumor cells in bone marrow; several clinical studies have demonstrated that cells of the latter type are an independent prognostic factor at primary diagnosis. In this article we briefly summarize recent studies examining the presence of circulating tumor cells in the blood and discuss further clinical applications.     

Circulating tumor DNA and circulating tumor cells in metastatic triple negative breast cancer patients

Circulating tumor DNA (ctDNA) is a new circulating tumor biomarker which might be used as a prognostic biomarker in a way similar to circulating tumor cells (CTCs). Here, we used the high prevalence of TP53 mutations in triple negative breast cancer (TNBC) to compare ctDNA and CTC detection rates and prognostic value in metastatic TNBC patients. Forty patients were enrolled before starting a new line of treatment. TP53 mutations were characterized in archived tumor tissues and in plasma DNA using two next generation sequencing (NGS) platforms in parallel. Archived tumor tissue was sequenced successfully for 31/40 patients. TP53 mutations were found in 26/31 (84%) of tumor samples. The same mutation was detected in the matched plasma of 21/26 (81%) patients with an additional mutation found only in the plasma for one patient. Mutated allele fractions ranged from 2 to 70% (median 5%). The observed correlation between the two NGS approaches (R² = 0.903) suggested that ctDNA levels data were quantitative. Among the 27 patients with TP53 mutations, CTC count was ≥1 in 19 patients (70%) and ≥5 in 14 patients (52%). ctDNA levels had no prognostic impact on time to progression (TTP) or overall survival (OS), whereas CTC numbers were correlated with OS (p = 0.04) and marginally with TTP (p = 0.06). Performance status and elevated LDH also had significant prognostic impact. Here, absence of prognostic impact of baseline ctDNA level suggests that mechanisms of ctDNA release in metastatic TNBC may involve, beyond tumor burden, biological features that do not dramatically affect patient outcome.     

Stem cell and epithelial-mesenchymal transition markers are frequently overexpressed in circulating tumor cells of metastatic breast cancer patients

Introduction  

The persistence of circulating tumor cells (CTC) in breast cancer patients might be associated with stem cell like tumor cells which have been suggested to be the active source of metastatic spread in primary tumors. Furthermore, these cells also may undergo phenotypic changes, known as epithelial-mesenchymal transition (EMT), which allows them to travel to the site of metastasis formation without getting affected by conventional treatment. Here we evaluated 226 blood samples of 39 metastatic breast cancer patients during a follow-up of palliative chemo-, antibody – or hormonal therapy for the expression of the stem cell marker ALDH1 and markers for EMT and correlated these findings with the presence of CTC and response to therapy.     

Epithelial-mesenchymal transition and cancer stem cells: a dangerously dynamic duo in breast cancer progression

Aberrant activation of a latent embryonic program - known as the epithelial-mesenchymal transition (EMT) - can endow cancer cells with the migratory and invasive capabilities associated with metastatic competence. The induction of EMT entails the loss of epithelial characteristics and the de novo acquisition of a mesenchymal phenotype. In breast cancer, the EMT state has been associated with cancer stem cell properties including expression of the stem cell-associated CD44⁺/CD24^-/low antigenic profile, self-renewal capabilities and resistance to conventional therapies. Intriguingly, EMT features are also associated with stem cells isolated from the normal mouse mammary gland and human breast reduction tissues as well as the highly aggressive metaplastic and claudin-low breast tumor subtypes. This has implications for the origin of these breast tumors as it remains unclear whether they derive from cells that have undergone EMT or whether they represent an expansion of a pre-existing stem cell population that expresses EMT-associated markers to begin with. In the present review, we consider the current evidence connecting EMT and stem cell attributes and discuss the ramifications of these newly recognized links for our understanding of the emergence of distinct breast cancer subtypes and breast cancer progression.     

Identification of genomic signatures in circulating tumor cells from breast cancer

Levels of circulating tumor cells (CTCs) in blood have prognostic value in early and metastatic breast cancer. CTCs also show varying degrees of concordance with molecular markers of primary tumors they originate from. It is expected that individual cells reflect the heterogeneity and evolution of tumor cells as they acquire new functions and differential responses to chemotherapy. However, a degree of commonality is also plausible, highlighting alterations that allow tumor cells to perform CTC‐defining activities such as invasion and intravasation. Using a matched tumor‐normal approach, we performed high‐resolution copy number profiling of CTCs from breast cancer to identify occult changes occurring during progression to metastasis. We identified a signature of recurrent gain in CTCs, consisting of 90 minimal common regions (MCRs) of copy number gain. These were predominantly found across chromosome 19 and were identified at low frequencies (3–4%) in 787 primary breast carcinomas examined. CTC genomic signatures clustered into two groups independent of subtype: a dormancy‐related signature with 16 MCRs (AKT2, PTEN, CADM2); and a tumor‐aggressiveness related signature with 358 MCRs (ANGPTL4, BSG, MIR‐373). There were two MCRs in common between the groups on 19q13 and 21q21, containing genes involved in resistance to anoikis, TGFβ‐signaling and metastasis (TFF3, LTBP4, NUMBL). Furthermore, a region harboring the ERBB2 gene was gained in a majority of patients. Regions 20q13 and 15q24 were associated with distant metastasis. The distinctiveness of CTC signatures highlights cell populations with different functional or metastatic potential. Such novel targets could help to specifically identify and block dissemination.     

乳腺癌循环肿瘤细胞检测及其研究进展

循环肿瘤细胞(CTC)为肿瘤发生转移的重要原因.检测CTC能早期发现肿瘤的转移及复发.在乳腺癌中,CTC检测与其他检测方式相比有较高的可重复性和敏感性,并能更早地提供预后信息.     

结直肠癌患者循环肿瘤细胞与临床病理特征的关系

目的:探讨外周血循环肿瘤细胞（circulating tumor cells,CTCs）在结直肠癌患者检测中的临床意义。方法:收集陕西省人民医院结直肠癌患者外周血标本57例,良性病变和健康受试者外周血标本29例。应用CyttelTM-CTC平台检测技术（即阴性富集技术结合免疫荧光原位杂交法）检测受试者外周血CTCs,搜集结直肠癌患者临床病理特征,采用统计学方法分析与其外周血CTCs之间的关系。结果:在Cut-off值≥2的结直肠癌患者中CTCs检出率为78.9%（45/57）,远高于良性病变及健康受试者中CTCs检出率的6.9%（2/29）（P＜0.05）。在Cut-off值≥3的结直肠癌患者中,发生淋巴转移的患者CTCs检出率为62.1%（18/29）,高于未发生淋巴转移患者CTCs检出率的32.1%（9/28）（P=0.024）。在Cut-off值≥4的结直肠癌患者中,周围组织侵犯患者CTCs检出率为53.8%（7/13）,高于周围组织未侵犯患者CTCs检出率的25.0%（11/44）（P=0.049）。在不同的病理分期中,与癌胚抗原（CEA）检测比较,CTCs检出率均高于CEA检出率。结论:CTC平台检测技术可有效检测结直肠癌患者外周血CTCs,CTCs计数分布与结直肠癌患者的病理分期显著相关,该技术敏感性高,准确性好,对于结直肠癌患者的临床诊断具有重要指导意义。     

Characterization of metastatic breast cancer patients with nondetectable circulating tumor cells

Circulating tumor cells (CTC) are an independent prognostic factor in metastatic breast cancer patients (MBC). However, CTC are undetectable in one third of patients. The aim of this study was to assess the prognostic factors in MBC patients without detectable CTC. This retrospective study included 292 MBC patients evaluated between January 2004 and December 2007. CTC were enumerated before patients started a new line of treatment using the CellSearch?. Overall survival (OS) was calculated from the date of CTC measurement and estimated by the Kaplan‐Meier product limit method. CTC were not detected in 35.96% patients, whereas 40.75% patients had CTC ≥ 5. Undetectable CTC status was positively correlated with presence of brain metastasis (OR: 6.17, 95%CI = 2.14–17.79; p = 0.001), and inversely correlated with bone metastasis (OR: 0.47; 95%CI = 0.27–0.80; p = 0.01). In multivariate analysis, hormone receptors, number of metastatic sites and lines of therapy were independent prognostic factors for OS in patients without detectable CTC. Patients without detectable CTC before starting of a new line of therapy comprise a heterogeneous group with substantially different prognosis. We showed that some important metastatic disease characteristics are predictive of undetectable CTC status in MBC.     

Role of circulating tumor cells and disseminated tumor cells in primary breast cancer

Metastasis remains a main cause of death in patients with breast cancer regardless of improvements in treatment. Prospective clinical studies of this minimal residual disease have shown disseminated tumor cells (DTCs) in bone marrow and circulating tumor cells (CTCs) in peripheral blood, neither of which can be detected by conventional imaging, to be prognostic and predictive markers for responsive treatment in patients with metastatic breast cancer. However, the guideline from the American Society of Clinical Oncology does not recommend measuring CTCs for clinical decisions because of a lack of evidence for an established, sound methodology and with proven clinical relevance. The Southwest Oncology Group trial S0500 to validate the clinical relevance of CTCs for treatment decisions in patients with metastatic breast cancer is ongoing. In patients with primary breast cancer, the low detection rate of CTCs has been overcome by recent advances in technology. Although generally DTCs were more detectable than CTCs and the association between presence of DTCs and poor prognosis has been shown, the invasiveness of sample collection of DTCs from bone marrow is generally hard for patients to accept. In this review, we concentrate on the question of whether we need to consider CTCs and DTCs in the management of primary breast cancer on the basis of the evidence of the clinical relevance of CTCs and DTCs. The promising role of the molecular characterization of CTCs, which does have the potential for being a predictor for tumor behavior and development, is suggested as a new targeting strategy.     

外周血循环肿瘤细胞数与乳腺癌患者临床病理特征的相关性研究

目的:探讨外周血循环肿瘤细胞（CTC）数与乳腺癌患者临床病理特征的相关性。方法:回顾性分析2017年1月至2020年5月广州市番禺区中心医院收治的104例乳腺癌患者临床资料,检测患者外周血CTC数、血清肿瘤标志物[甲胎蛋白（AFP）、癌胚抗原（CEA）、糖类抗原125（CA125）、糖类抗原153（CA153）]水平。...