M—CSF和RANKL联合诱导小鼠骨髓源破骨细胞形成的实验研究

目的探索小鼠骨髓单核细胞最佳诱导条件,以期提高破骨细胞（OC）的产生数量与纯度。方法采用梯度离心法分离得到小鼠骨髓单核细胞。分别对首日刺激所用的巨噬细胞集落刺激因子（M～CSF）的2．5ng／ml～160．0ng／ml 7个浓度、16h与24h两个处理时间,以及次日诱导所用的核因子κB受体活化因子配体（RANKL）和M—CSF12．5ng／ml～100．0ng／ml的16个浓度组合进行检测,比较OC产生的情况。以相差显微镜观察细胞形态变化,抗酒石酸酸性磷酸酶（TRAP）染色法进行OC计数。结果产生的体积大、TRAP染色阳性的多核细胞为OC。首日M—CSF刺激浓度为10ng／ml-20ng／ml组形成的OC数量最多沪〈0．05）。处理16h组与24h组比较,OC形成率没有统计学差异（30．24±2．84个／孔vs31．22±3．25个／孔,P〉0．05）。次日诱导采用100ng/ml M—CSF＋100ng／ml RANKL组的OC得率最高;在该条件下,OC数量在第9d达峰值,18d消失。结论体外OC诱导分化的适宜条件为首先用10ng／ml M—CSF将小鼠骨髓单核细胞刺激16～24h,然后用100ng／ml M—CSF＋100ng／ml RANKL对非贴壁细胞联合诱导9d。     

Prognostic significance of bone markers in patients with lung cancer metastatic to the skeleton: a review of published data

The presence of bone metastases significantly affects clinical outcome and quality of life parameters in patients with lung cancer. In this review, we aimed to evaluate the predictive value of markers of bone turnover in skeletal morbidity and clinical parameters, including disease-free survival (DFS) and overall survival (OS), in patients with lung cancer metastatic to the skeleton who were receiving bisphosphonate treatment. A comprehensive overview of all articles published from 1995 to date in 3 medical databases (PubMed, Scopus, and Cochrane) was performed using the keywords bone markers and lung cancer. Most bone formation markers (including bone alkaline phosphatase [bALP], osteocalcin [OC], and osteoprotegerin [OPG]), most bone absorption markers (including urinary calcium, osteopontin [OPN], receptor activator of nuclear factor κ-B ligand [RANKL], tartrate-resistant acid phosphatase isoform-5b [TRACP 5b]), and the metabolites of type I collagen had elevated concentrations in patients with lung cancer and bone metastases compared with patients without skeletal involvement. Two large studies showed that urinary N-terminal telopeptide (NTX) levels are a valid diagnostic method for early detection of bone metastases and a more consistent prognosticator than bALP. Treatment with zoledronic acid reduces NTX, TRACP-5b, RANKL, and OPG levels. Furthermore posttherapeutic reduction of urinary NTX levels seems to correlate with lower risk of skeletal-related events (SREs). Levels of markers of bone remodeling reflect the presence of bone metastases and may contribute to early detection of occult skeletal disease or monitor the effect of bisphosphonate treatment. However their ability to predict SREs, as well as DFS and OS, remains debatable.     

OPG/RANKL/RANK Pathway as a Therapeutic Target in Cancer

Bone metastases play an important role in the morbidity and mortality of patients with malignant disease. Despite therapeutic advances in the treatment of solid organ malignancy such as lung cancer, less development on metastasis interventions has been forthcoming. More recent research has focused on molecular pathway manipulation in the prevention and treatment of metastatic bone disease and associated complications such as bone pain and hypercalcemia. The osteoprotegerin/receptor activator of nuclear factor-кβ ligand/receptor activator of nuclear factor-кβ pathway, which is physiologically involved in bone turnover, has been of considerable interest, and recent promising data have been revealed. In this study, we describe this molecular pathway in terms of its natural physiological function, manipulation for therapeutic benefit, and recent clinical trial results.     

The RANK/RANKL/OPG triad in cancer-induced bone diseases

The maintenance of skeletal integrity in a healthy individual requires a balanced regulation of the processes of bone formation, mediated by osteoblasts, and bone resorption, mediated by osteoclasts. This balanced process of bone remodeling becomes co-opted in the skeleton by tumor cells and this dramatically accelerates the process of remodeling and disrupts the normal equilibrium resulting in a spectrum of osteolytic to osteoblastic bone lesions. Certain tumor types, such as breast and prostate, frequently metastasize to the bone. It is now widely understood that the molecular triad—receptor activator of NF-κB ligand (RANKL), its receptor RANK, and the endogenous soluble RANKL inhibitor, osteoprotegerin (OPG)—play direct and essential roles in the formation, function, and survival of osteoclasts. Osteoclastic bone resorption contributes to the majority of skeletal sequelae, or skeletal-related events (SREs), in patients with bone metastases. In addition, osteoclastic bone resorption also contributes to the establishment of tumors in the skeleton. Therefore, blocking osteoclast activity and differentiation via RANKL inhibition may not only provide a beneficial treatment for skeletal complications of malignancy, but may also prevent bone metastases. In this review, we will first describe the operative role of osteoclasts and the RANK/RANKL/OPG triad in the pathophysiology of cancer-induced bone diseases, specifically solid tumor metastases to the bone. Secondly, we will describe a therapeutic approach that specifically targets the RANKL molecule.     

Plasma levels of receptor activator of nuclear factor-kappaB ligand and osteoprotegerin in patients with neuroblastoma

Earlier reports showed that the balance between receptor activator of nuclear factor-kappaB ligand (RANKL) and its decoy-receptor osteoprotegerin (OPG) plays an important role in the pathogenesis of metastatic osteolysis induced by neuroblastoma cells. In this study, we investigated whether circulating levels of OPG, RANKL and their ratio were associated to the presence of osteolytic lesions in advanced neuroblastoma, as well as whether they provided additional information on the severity and prognosis of the disease. Plasma levels of RANKL and OPG were measured in 54 newly diagnosed neuroblastomas; 27 of them showed metastatic disease (stage IV), including 19 bone dissemination. Thirty-five children who were admitted to the pediatric department for minor surgical problems served as control group. OPG was significantly lower in all patients compared with controls, while RANKL levels were significantly increased in advanced neuroblastoma. OPG-to-RANKL ratio decreased in stage-IV patients, and particularly in those who had bone metastases. The diagnostic accuracy of the OPG-to-RANKL ratio in discriminating the presence of osteolytic lesions was not confirmed statistically. OPG correlated significantly with other prognostic factors, namely, ferritin and neurone-specific enolase. In addition, an inverse relationship was found between OPG and event-free survival, and it was more significant in patients who had bone metastasis. This pilot study confirms that the production of OPG and RANKL is disregulated in neuroblastoma. Although the OPG-to-RANKL ratio does not have a predictive value in detecting bone metastasis, the measurement of the previously mentioned markers could be useful in decisions regarding the use of adjuvant therapies.     

The central role of osteoblasts in the metastasis of prostate cancer

Prostate cancer (PCa) is the most common malignancy in men. Although mortality from PCa has been declining over the past decade, metastasis can substantially shorten survival time and remains a major challenge in maintaining quality of life for survivors. PCa cells preferentially metastasize to bone and typically result in osteoblastic lesions. In the late stages of disease, however, osteolytic lesions are observed. The mechanisms of PCa bone metastasis are still unclear, but relationships between the PCa cells and the bone tissue elements are suspected of being more complex than initially thought. Far from being an innocent bystander, the bone participates actively in the metastatic process and provides the cancer cells with growth factors and a fertile environment. Among the various cells in the bone environment, osteoblasts have a central role through their bidirectional interactions with the PCa cells. This review discusses the possible mechanisms of PCa bone metastasis and highlights the essential role of osteoblasts in the metastasis of PCa to bone.     

多发性骨髓瘤骨病患者白细胞介素-17的表达及其意义

 【摘要】　目的　研究多发性骨髓瘤（MM）骨病患者骨髓中白细胞介素17（IL-17）的表达水平及其与骨髓单个核细胞核因子κB受体活化因子配体（RANKL）表达的关系,探讨IL-17在MM骨病发病机制中的作用及其临床意义。方法　采用双抗体夹心酶联免疫吸附（ELISA）法检测33例MM骨病患者及20例对照者骨髓上清中IL-17水平,采用荧光定量PCR检测上述两组骨髓单个核细胞RANKL mRNA的表达。 结果　MM骨病组及对照组的骨髓上清均表达IL-17,骨髓单个核细胞均表达RANKL mRNA。MM骨病组骨髓上清中IL-17的含量［（52.69±4.55）pg／ml］高于对照组［（14.35±1.25）pg／ml］,MM骨病组骨髓单个核细胞RANKL mRNA的表达［（0.96±0.12）pg／ml］高于对照组［（0.42±0.03）pg／ml］,差异均有统计学意义（P＜0.05）。活动期MM骨病患者骨髓IL-17［（76.71±7.06）pg／ml］水平显著高于稳定期MM骨病患者［（40.67±3.84）pg／ml］,差异有统计学意义（P＜0.05）,活动期MM骨病患者骨髓单个核细胞RANKL mRNA的表达水平（1.22±0.27）显著高于稳定期MM骨病患者（0.83±0.12）,差异有统计学意义（P＜0.05）。MM骨病组骨髓IL-17与RANKL的表达呈显著正相关（r＝0.690,P＜0.05）。结论　MM骨病患者骨髓IL-17的表达显著增高,骨髓IL-17水平与MM活动期和（或）稳定期相关,骨髓IL-17与RANKL的表达呈正相关,IL-17可能在MM骨病的发病机制中起重要的作用。     

分析吉非替尼有效的非小细胞肺癌患者骨转移对其生存期的影响及骨转移患者的预后因素

目的：研究吉非替尼有效的非小细胞肺癌患者,骨转移是否影响其生存期,并分析骨转移患者的预后因素。方法比较骨转移和无骨转移患者总生存、无进展生存、1年、2年及3年生存率,并分析影响骨转移患者预后的因素。结果无骨转移组44例,骨转移组32例。无骨转移组与有骨转移组总生存期（19．000±3．317月 vs．26．000±2．121月,P＝0．625）和无进展生存期（14．000±1．843月 vs．16．000±1．411月,P＝0．328）无统计学差异。前组患者1年生存率63．6％低于后者96．9％,2年和3年生存率分别为（34．1％vs．56．3％,P＝0．054）和（18．2％vs．18．4％,P＝0．950）,无统计学差异。对骨转移组进行单因素分析显示年龄＞60岁及有肺内进展者预后更差,多因素分析显示影响骨转移患者生存的有效因素为有肺内进展,而性别、病理、吸烟指数、是否合并脑转移、骨相关事件及是否应用放疗、双膦酸盐与骨转移患者中位生存时间均无明显相关性。结论吉非替尼治疗有效的非小细胞肺癌患者,骨转移可能不是影响其生存期的主要因素,肺内进展有可能是非小细胞肺癌骨转移者的主要死因,不能将骨转移作为停用吉非替尼的指征。     

骨代谢指标检测在乳腺癌骨转移早期诊断中的应用价值

目的探讨骨代谢指标血清骨钙素（GBP）、Ⅰ型胶原羧基末端肽（ICTP）和尿羟脯氨酸（uHOP）早期诊断乳腺癌骨转移的应用价值。方法对86例原发性乳腺癌和20例正常女性分别采用放射免疫法测定血清BGP、ICTP和uHOP,用ECT核素骨扫描确定乳腺癌有无骨转移。结果无骨转移乳腺癌患者与正常人之间血清BGP、ICTP和uHOP水平差异无统计学意义（P〉0．05）,随访2年中32例血清BGP、ICTP和UHOP水平升高,其中29例平均在3个月后ECT核素骨扫描示骨转移,骨转移后血清BGP、ICTP和uHOP水平较转移前明显升高（P〈0．01）。结论血清GBP、ICTP和uHOP在乳腺癌骨转移的早期诊断方面有重要应用价值,且能比LECT核素骨扫描较早发现骨转移。     

Effects of anastrozole combined with Shuganjiangu decoction on osteoblast-like cell proliferation, differentiation and OPG/RANKL mRNA expression

Objective: To investigate the effects of anastrozole combined with Shuganjiangu decoction on osteoblast-like cells. Methods: Human osteoblast-like cells MG-63 were cultured and divided into four groups: control, anastrozole, Shuganjiangu decoction (SGJGD), and anastrozole combined with SGJGD. Cell proliferation was investigated by MTT assay. Alkaline phosphatase (ALP) and osteocalcin, the indicators of cell differentiation, were evaluated by p-nitrophenyl-phosphate method and radioimmunoassay, respectively. Gene expressions of ALP, osteocalcin, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) were examined by real-time PCR. Results: As evidenced by MTT assay, cell proliferation of MG-63 was inhibited by anastrozole, but stimulated with treatment of SGJGD alone and combined with anastrozole (P<0.01). Compared with control group, ALP activity was increased by the treatment of SGJGD alone and combined with anastrozole (P<0.01). Also, osteocalcin secretion was enhanced with the treatment of SGJGD single and combination with anastrozole (P<0.05). In the real-time PCR assay, gene expressions of ALP and osteocalcin were significantly increased (P<0.01 for ALP, P<0.05 for osteocalcin) by the treatment of SGJGD and anastrozole combined with SGJGD, but the expression of RANKL was decreased (P<0.05). Moreover, anastrozole combined with SGJGD upregulated gene expression of OPG (P<0.01). Conclusion: SGJGD may alleviate the injury effects of anastrozole on MG-63 cells through adjusting bone formation and resorption indicators.     

The multifaceted role of extracellular vesicles in metastasis: Priming the soil for seeding

Extracellular vesicles (EVs), including exosomes, play a key role in inter and intracellular communication, promoting the proliferation and invasion of recipient cells to support tumor growth and metastasis. Metastasis comprises multiple steps that first include the detachment of tumor cells through epithelial to mesenchymal transition (EMT), allowing the physical dissemination to distant organs. Thereafter, cancer‐derived exosomes are still critical components for preparing the tumor microenvironment by (i) enabling tumor cells to escape from the immunological surveillance and (ii) arranging the pre‐metastatic site for the engraftment of detached cancer cells. In this review, we discuss the multifaceted role of EVs in the multiple steps of metastasis. Future research directions draw attention to EVs as biological targets for cancer diagnosis, prognosis and therapy. However, due to their significant role in cell communication, they may become a valuable drug delivery system.     

以骨转移为首发症状的分化型甲状腺癌的临床特征与生存分析

目的:探讨以骨转移为首发症状的分化型甲状腺癌(differentiated thyroid carcinoma,DTC)的临床特征,并进行生存分析。方法:对拟行131I治疗的1546例DTC患者的临床资料进行回顾性分析,收集以骨转移为首发症状的DTC患者的资料,分析骨转移情况,并进行生存分析。结果:DTC骨转移患者共120例,其中以骨转移为首发症状的DTC患者28例(23.3%,28/120),其中滤泡状癌20例、乳头状癌6例、乳头状癌滤泡亚型2例。临床症状表现为骨骼疼痛者26例(92.9%),其中腰椎病理性骨折1例,股骨病理性骨折2例。无骨痛者2例,分别为体检时发现枕骨和肋骨DTC转移。28例患者骨转移灶共73处,以骨盆和椎体转移最多见(63.0,46/73),其中12例患者伴有其他部位的远处转移(42.9%)。本组以骨转移为首发症状的DTC患者的5年和10年生存率分别为93.0%和71.0%;与甲状腺癌术后诊断为骨转移的DTC患者(92例)相比,以骨转移为首发症状诊断为DTC患者的20年生存率更高(P=0.012)。结论:部分DTC发病较为隐匿,当临床发现原因不明的局部骨骼疼痛、病理学骨折或骨质破坏时,应排除DTC骨转移可能。以骨转移为首发症状诊断为DTC患者的预后要优于甲状腺癌术后诊断为骨转移的DTC患者。     

Gene silencing of the BDNF/TrkB axis in multiple myeloma blocks bone destruction and tumor burden in vitro and in vivo

Osteolytic bone diseases are a prominent feature of multiple myeloma (MM), resulting from aberrant osteoclastic bone resorption that is uncoupled from osteoblastic bone formation. Myeloma stimulates osteoclastogenesis, which is largely dependent on an increase in receptor activator of NF‐κB ligand (RANKL) and a decrease in osteoprotegerin (OPG) within the bone marrow milieu. Recently, brain‐derived neurotrophic factor (BDNF) was identified as a MM‐derived factor that correlates with increased RANKL levels and contributes to osteolytic bone destruction in myeloma patients. Because tyrosine receptor kinase B (TrkB), the receptor of BDNF, is abundantly expressed in osteoblasts, we sought to evaluate the role of BDNF/TrkB in myeloma–osteoblast interactions and the effect of this pathway on the RANKL/OPG ratio and osteoclastogenesis. Coculture systems constructed with noncontact transwells revealed that, in vitro, MM‐derived BDNF increased RANKL and decreased OPG production in osteoblasts in a time‐ and dose‐dependent manner. These effects were completely abolished by a specific small interfering RNA for TrkB. BDNF regulates RANKL/OPG expression in osteoblasts through the TrkB/ERK pathway. To investigate the biological effects of BDNF on myeloma in vivo, a SCID‐RPMI8226 mice model was constructed using lentiviral short hairpin RNA‐transfected RPMI8226 cells. In this system, stable knockdown of BDNF in MM cells significantly restored the RANKL/OPG homostasis, inhibited osteolytic bone destruction and reduced angiogenesis and tumor burden. Our studies provide further support for the potential osteoclastogenic effects of BDNF, which mediates stroma–myeloma interactions to disrupt the balance of RANKL/OPG expression, ultimately increasing osteoclastogenesis in MM.     

The importance of microenvironment: the role of CCL8 in metastasis formation of melanoma

We have attempted to characterize the changes occurring on the host side during the progression of human melanoma. To investigate the role of tumor microenvironment, we set up such an animal model, which was able to isolate the host related factors playing central role in metastasis formation. One of these ‘factors’, CCL12, was consequently selected and its behavior was examined alongside its human homologue (CCL8). In our animal model, metastasis forming primary melanoma in the host exhibited increased level of CCL12 mRNA expression. In clinical samples, when examining the tumor and the host together, the cumulative (tumor and host) CCL8 expression was lower in the group in which human primary melanoma formed lung metastasis compared to non-metastatic primary tumors. We could not detect significant difference in CCL8 receptor (CCR1) expression between the two groups. Increased migration of the examined tumor cell lines was observed when CCL8 was applied as a chemoattractant. The tumor cells and their interactions can be influenced the expression of CCL8 by dermal fibroblasts, as a significant change in the metastatic microenvironment. Furthermore, we examined changes in miRNA profile resulted by CCL8 and miR146a appears to be a promising prognostic marker for following this process.     

Immunohistochemical study of receptor activator of nuclear factor kappa-B ligand (RANK-L) in human osteolytic bone tumors

BACKGROUND AND OBJECTIVES: Osteolytic bone tumors produce intercellular signaling proteins that regulate bone remodeling by altering the rates of osteoclast and osteoblast differentiation and activity. This report examines osteolytic bone tumor expression of receptor activator of nuclear factor B-ligand (RANK-L), a cytokine that is arguably the most critical regulator of osteoclast differentiation and activation. METHODS: This prospective immunohistochemical study examined RANK-L expression in frozen tissues from sixteen surgical specimens of patients who underwent surgery for the treatment of osteolytic bone tumors between 1999 and 2000. RESULTS: RANK-L was positive in 13 of the 16 cases. Primary benign bone tumors, primary malignant bone tumors, and metastasis to bone were positive for RANK-L. CONCLUSIONS: The cells in some, but not all, osteolytic tumors produce the cytokine RANK-L. Further study is necessary to determine in which specific tumors RANK-L is the cytokine responsible for increased osteoclastic activity, and to develop possible therapeutic use of RANK-L antagonists such as osteoprotegerin (OPG).     

Role of proteolytic enzymes in human prostate bone metastasis formation: in vivo and in vitro studies

Prostate cancers ability to invade and grow in bone marrow stroma is thought to be due in part to degradative enzymes. The formation of prostate skeletal metastases have been reproduced in vitro by growing co-cultures of prostatic epithelial cells in bone marrow stroma. Expression of urokinase plasminogen activator, matrix metalloproteinase 1 and 7 by prostatic epithelial cells were identified using immunocytochemistry. Also, in vivo tissue sections from human prostatic bone marrow metastases were stained. To establish the role of these enzymes on colony formation, inhibitory antibodies directed against urokinase plasminogen activator, matrix metalloproteinase 1 and matrix metalloproteinase 7 were added into primary prostatic epithelial cells and bone marrow stroma co-cultures. All prostatic epithelial cell cultures stained positively for matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator. Generally prostatic epithelial cells derived from malignant tissues showed increased staining in comparison to epithelia derived from non-malignant tissue. In agreement with in vitro co-cultures, the in vivo tissue sections of prostate bone marrow metastases showed positive staining for all three enzymes. Inhibition studies demonstrated that blocking matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator function reduced the median epithelial colony area significantly in bone marrow stroma co-cultures in vitro. Using a human ex-vivo model we have shown that matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator play an important role in the establishment of prostatic epithelial cells within bone marrow.     

Immune mediators in the tumor microenvironment of prostate cancer

Prostate cancer tissue is composed of both cancer cells and host cells. The milieu of host components that compose the tumor is termed the tumor microenvironment (TME). Host cells can be those derived from the tissue in which the tumor originates (e.g., fibroblasts and endothelial cells) or those recruited, through chemotactic or other factors,to the tumor (e.g., circulating immune cells). Some immune cells are key players in the TME and represent a large proportion of non-tumor cells found within the tumor. Immune cells can have both anti-tumor and pro-tumor activity.In addition, crosstalk between prostate cancer cells and immune cells affects immune cell functions. In this review,we focus on immune cells and cytokines that contribute to tumor progression. We discuss T-regulatory and T helper 17 cells and macrophages as key modulators in prostate cancer progression. In addition, we discuss the roles of interleukin-6 and receptor activator of nuclear factor kappa-B ligand in modulating prostate cancer progression. This review highlights the concept that immune cells and cytokines offer a potentially promising target for prostate cancer therapy.     

早期应用双磷酸盐对老年非小细胞肺癌骨转移的作用

目的:探讨早期静脉应用双磷酸盐对老年非小细胞肺癌骨转移的作用。方法:研究老年非小细胞肺癌患者68例。将骨密度T-Score≤-2.5作为双磷酸盐应用指征,在确诊骨转移之前即开始应用双磷酸盐定义为早期应用。按是否早期应用双磷酸盐,将68例患者按照临床分期分为两组,早期应用双磷酸盐者34例为治疗组,未早期应用者34例为对照组。比较两组骨转移发生率及确诊时间。结果:治疗组骨转移发生率47.06%(16/34),对照组82.35%(28/34),差异有统计学意义（P≤0.01)。治疗组中位骨转移发生时间较对照组延迟87天（218天 vs 131天）,差异有统计学意义（P=0.006）。结论:早期应用双磷酸盐治疗经选择的老年非小细胞肺癌患者,可以减少骨转移发生率,并推迟骨转移发生时间。     

Intracranial astrocytoma with diffuse bone marrow metastasis: a case report and review of the literature

A 41 year old male presented with headache, lethargy, and ataxia and found to have a left temporal lobe mass and a leukoerythroblastic peripheral blood smear. The latter prompted an iliac crest bone marrow biopsy on which a diagnosis of metastatic glioma was made and verified by immunohistologic characterization. The patient was treated with cranial irradiation and simultaneous systemic BCNU (bis-dichloroethylnitrosurea) with complete response. This case with diffuse bone marrow involvement demonstrates that a glioblastoma is capable of extracranial metastases without previous intervention. From a review of reported cases of gliomas of extraneural metastasis, it is concluded that untreated gliomas are capable of vascular spread although less frequently than previously manipulated tumors.     

The metastatic microenvironment: Lung‐derived factors control the viability of neuroblastoma lung metastasis

Recent data suggest that the mechanisms determining whether a tumor cell reaching a secondary organ will enter a dormant state, progress toward metastasis, or go through apoptosis are regulated by the microenvironment of the distant organ. In neuroblastoma, 60–70% of children with high‐risk disease will ultimately experience relapse due to the presence of micrometastases. The main goal of this study is to evaluate the role of the lung microenvironment in determining the fate of neuroblastoma lung metastases and micrometastases. Utilizing an orthotopic mouse model for human neuroblastoma metastasis, we were able to generate two neuroblastoma cell populations—lung micrometastatic (MicroNB) cells and lung macrometastatic (MacroNB) cells. These two types of cells share the same genetic background, invade the same distant organ, but differ in their ability to create metastasis in the lungs. We hypothesize that factors present in the lung microenvironment inhibit the propagation of MicroNB cells preventing them from forming overt lung metastasis. This study indeed shows that lung‐derived factors significantly reduce the viability of MicroNB cells by up regulating the expression of pro‐apoptotic genes, inducing cell cycle arrest and decreasing ERK and FAK phosphorylation. Lung‐derived factors affected various additional progression‐linked cellular characteristics of neuroblastoma cells, such as the expression of stem‐cell markers, morphology, and migratory capacity. An insight into the microenvironmental effects governing neuroblastoma recurrence and progression would be of pivotal importance as they could have a therapeutic potential for the treatment of neuroblastoma residual disease.