Women with epithelial ovarian cancer (EOC) are usually treated with platinum/taxane therapy after cytoreductive surgery but there is considerable inter-individual variation in response. To identify germline single-nucleotide polymorphisms (SNPs) that contribute to variations in individual responses to chemotherapy, we carried out a multi-phase genome-wide association study (GWAS) in 1,244 women diagnosed with serous EOC who were treated with the same first-line chemotherapy, carboplatin and paclitaxel. We identified two SNPs (rs7874043 and rs72700653) in TTC39B (best P=7x10-5, HR=1.90, for rs7874043) associated with progression-free survival (PFS). Functional analyses show that both SNPs lie in a putative regulatory element (PRE) that physically interacts with the promoters of PSIP1, CCDC171 and an alternative promoter of TTC39B. The C allele of rs7874043 is associated with poor PFS and showed increased binding of the Sp1 transcription factor, which is critical for chromatin interactions with PSIP1. Silencing of PSIP1 significantly impaired DNA damage-induced Rad51 nuclear foci and reduced cell viability in ovarian cancer lines. PSIP1 (PC4 and SFRS1 Interacting Protein 1) is known to protect cells from stress-induced apoptosis, and high expression is associated with poor PFS in EOC patients. We therefore suggest that the minor allele of rs7874043 confers poor PFS by increasing PSIP1 expression.

The neurotransmitter acetylcholine (ACh) promotes the growth and metastasis of several cancers via its M3 muscarinic receptor (M3R). Metastasis-associated in colon cancer-1 (MACC1) is an oncogene that is overexpressed in gastric cancer (GC) and plays an important role in GC progression, though it is unclear how MACC1 activity is regulated in GC. In this study, we demonstrated that ACh acts via M3Rs to promote GC cell invasion and migration as well as expression of several markers of epithelial-mesenchymal transition (EMT). The M3R antagonist darifenacin inhibited GC cell activity in both the presence and absence of exogenous ACh, suggesting GC cells secrete endogenous ACh, which then acts in an autocrine fashion to promote GC cell migration/invasion. ACh up-regulated MACC1 in GC cells, and MACC1 knockdown using siRNA attenuated the effects of ACh on GC cells. AMP-activated protein kinase (AMPK) served as an intermediate signal between ACh and MACC1. These findings suggest that ACh acts via a M3R/AMPK/MACC1 signaling pathway to promote GC cell invasion/migration, which provides insight into the mechanisms underlying GC growth and metastasis and may shed light on new targets for GC treatment.

Cancer immunotherapy is the use of the immune system to treat cancer. Our current research proposed an optional strategy of activating immune system involving in cancer immunotherapy. When being treated with 2% DMSO in culture medium, Hepa1-6 cells showed depressed proliferation with no significant apoptosis or decreased viability. D-hep cells, Hepa1-6 cells treated with DMSO for 7 days, could restore to the higher proliferation rate in DMSO-free medium, but alteration of gene expression profile was irreversible. Interestingly, tumors from D-hep cells, not Hepa1-6 cells, regressed in wild-type C57BL/6 mice whereas D-hep cells exhibited similar tumorigenesis as Hep1-6 cells in immunodeficient mice. As expected, additional Hepa1-6 cells failed to form tumors in the D-hep-C57 mice in which D-hep cells were eliminated. Further research confirmed that D-hep-C57 mice established anti-tumor immunity against Hepa1-6 cells. Our research proposed viable tumor cells with altered biological features by DMSO-treatment could induce anti-tumor immunity in vivo.

Reverse-transcription polymerase chain reaction (RT-PCR) is used to detect CK19 mRNA in sentinel lymph node biopsy (SLNB) tissues from breast cancer patients. We examined whether CK19 mRNA in peripheral blood is predictive of non-sentinel lymph node (nSLN) metastasis. Breast cancer cases diagnosed with clinical stage cT1-3cN0 and registered in our medical biobank were identified retrospectively. This study then included 120 breast cancer cases treated at Zhejiang Cancer Hospital from Aug 2014 to Aug 2015, including 60 SLN-positive and 60 SLN-negative cases. CK19 mRNA levels in peripheral blood samples were assessed using RT-PCR prior to tumor removal. During surgery, if SLNB tissue showed evidence of metastasis, axillary lymph node dissection (ALND) was performed. No ALND was performed if SLNB and nSLN tissues were both negative for metastasis. CK19 expression was higher in nSLN-positive patients than in nSLN-negative patients (p < 0.05). Logistic regression indicated that lymphatic vessel invasion and CK19 levels were predictive of nSLN status (p < 0.05). The area under the ROC curve for CK19 was 0.878 (p < 0.05). We conclude that high CK19 levels in peripheral blood may independently predict nSLN metastasis in breast cancer patients.

Liver cancer is the second-most frequent cause of cancer death in the world and is highly treatment resistant. We reported previously that inhibition of neddylation pathway with specific NAE inhibitor MLN4924, suppressed the malignant phenotypes of liver cancer. However, during the process, MLN4924 induces pro-survival autophagy as a mechanism of drug resistance. Here, we report that blockage of autophagy with clinically-available autophagy inhibitors (e.g. chloroquine) significantly enhanced the efficacy of MLN4924 on liver cancer cells by triggering apoptosis. Mechanistically, chloroquine enhanced MLN4924-induced up-regulation of pro-apoptotic proteins (e.g. NOXA) and down-regulation of anti-apoptotic proteins. Importantly, the down-regulation of NOXA expression via siRNA silencing substantially attenuated apoptosis of liver cancer cells. Further mechanistic studies revealed that blockage of autophagy augmented MLN4924-induced DNA damage and reactive oxygen species (ROS) generation. The elimination of DNA damage or blockage of ROS production significantly reduced the expression of NOXA, and thereby attenuated apoptosis and reduced growth inhibition of liver cancer cells. Moreover, blockage of autophagy enhanced the efficacy of MLN4924 in an orthotopic model of human liver cancer, with induction of NOXA and apoptosis in tumor tissues. These findings provide important preclinical evidence for clinical investigation of synergistic inhibition of neddylation and autophagy in liver cancer.

Malignant mesothelioma (MM) has become a global disease burden for its rising incidence and invariable fatality. D2-40 has been widely used as an immunostaining marker of diagnosing MM, while its diagnostic value has not yet been evaluated. Our study aimed to assess the overall accuracy of D2-40 immunostaining for diagnosing MM through a meta-analysis. A total of 22 studies with 2,264 participants were identified from PubMed, EMBASE, Web of Science, Scopus and the Cochrane database. The pooled sensitivity and specificity of D2-40 for MM was 0.86 (95% CI: 0.84-0.89) and 0.77 (95% CI: 0.74-0.79), respectively. The area under the summary receiver operating characteristic curve is 0.93, with a diagnostic odds ratio 40.37 (95% CI: 19.97-81.61). None of the study variates was found to be a source of heterogeneity after meta-regression analysis. In conclusion, D2-40 immunostaining may not give sufficient evidence by itself to diagnose MM and should be in combination with other markers to improve the accuracy of diagnosis.

Pancreatic ductal adenocarcinoma (PanCa) is an extremely lethal disease characterized by mutations of p53 in up to 70% of cases. Our previous studies have confirmed that hyperglycemia may be the first clinical manifestation for the early diagnosis of PanCa. In this article, we showed that targeted knockdown of TG2 or p53 in tumor cells led to decreased cell survival in response to glucose deprivation, while this phenomenon was abolished by combined inhibition of TG2 and p53. We observed that inhibition of TG2 or p53 sensitized glucose deprivation resistance through an intracellular reactive oxygen species (ROS) pathway and the induction of Bcl-2. Moreover, to understand whether pancreatic cancer cells with TG2 and p53 combined interference had possible effects on pancreatic β cells, we performed studies comparing pancreatic cancer cells with TG2 and p53 combined interference and pancreatic β cells. We discovered that the supernatant of pancreatic cancer cells withTG2 and p53 combined interference decreased cell survival in pancreatic β cells. Following the creation of an orthotopic pancreatic cancer mouse model, we revealed glucose tolerance abnormalities in the pancreatic cancer mouse model with TG2 and p53 combined interference, indicating a possible mechanism for damage of βcells in pancreatic cancer. Taken together, our findings establish roles for TG2 and p53 in response to glucose deprivation in pancreatic cancer cells. The relationship between TG2 and p53 suggests a possible mechanism for glucose tolerance abnormalities-associated pancreatic cancer and could have therapeutic potential for cancer treatment and diagnosis.

The postoperative recurrence risk of gastrointestinal stromal tumour (GIST) should be estimated when considering adjuvant systemic therapy. Previous studies in the literature have suggested that small intestinal GISTs are more aggressive than gastric GISTs. We assessed the prognostic role of the primary tumour site in patients with operable GIST to compare the outcomes of gastric and small intestinal GISTs over a decade of treatment. The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of gastric and small intestinal GISTs between 2004 and 2014 using the GIST-specific histology code (ICD-O-3 code 8936), and only patients with tissues sampled by surgical resection were selected for this study. Cancer-specific survival (CSS) and overall survival (OS) were compared between small intestinal and gastric GISTs using Cox regression analyses. GISTs were located in the stomach (n = 2594, 65%), duodenum (n = 228, 6%), and jejunum/ileum (n = 1176, 29%). The OS and CSS of patients with GISTs in the duodenum and jejunum/ileum were similar to those of patients with gastric GISTs in Cox regression analyses, except for the CSS of patients with tumour sizes 2.1-5 cm in diameter and ≤ 5 mitoses per 50 HPFs (HR 1.657; 95% CI 1.062-2.587, p = 0.026). Tumours sizes 2.1-5 cm in diameter and > 5 mitoses per 50 HPFs (HR 4.627; 95% CI 1.035-20.67, p = 0.045) in jejunal/ileal GIST locations had significantly worse CSS than did those in gastric GIST locations. In this large nationwide study, the primary tumour site was not an independent prognostic factor in patients with operable small intestinal and gastric GISTs.

Autophagy is a conserved multi-step lysosomal process that is induced by diverse stimuli including cellular nutrient deficiency. X-linked inhibitor of apoptosis (XIAP) promotes cell survival and recently has been demonstrated to suppress autophagy. Herein, we examined regulation of XIAP-mediated autophagy in breast cancer cells and determined the underlying molecular mechanism. To investigate this process, autophagy of breast cancer cells was induced by Earle's balanced salt solution (EBSS). We observed discordant expression of XIAP mRNA and protein in the autophagic process induced by EBSS, suggesting XIAP may be regulated at a post-transcriptional level. By scanning several miRNAs potentially targeting XIAP, we observed that forced expression of miR-23a significantly decreased the expression of XIAP and promoted autophagy, wherever down-regulation of miR-23a increased XIAPexpression and suppressed autophagy in breast cancer cells. XIAP was confirmed as a direct target of miR-23a by reporter assay utilizing the 3'UTR of XIAP. In vitro, forced expression of miR-23a promoted autophagy, colony formation, migration and invasion of breast cancer cell by down-regulation of XIAP expression. However, miR-23a inhibited apoptosis of breast cancer cells independent of XIAP. Xenograft models confirmed the effect of miR-23a on expression of XIAP and LC3 and that miR-23a promoted breast cancer cell invasiveness. Therefore, our study demonstrates that miR-23a modulates XIAP-mediated autophagy and promotes survival and migration in breast cancer cells and hence provides important new insights into the understanding of the development and progression of breast cancer.

Ankylosing spondylitis (AS) is a chronic autoimmune disease characterized by systemic inflammation and pathological osteogenesis. However, the genetic etiology of AS remains largely unknown. This study aimed to explore the potential role of coding and noncoding genes in the genetic mechanism of AS. Using microarray analyses, this study comprehensively compared lncRNA, microRNA, and mRNA profiles in hip joint ligament tissues from patients with AS and controls. A total of 661 lncRNAs, 574 mRNAs, and 22 microRNAs were differentially expressed in patients with AS compared with controls. Twenty-two of these genes were then validated using real-time polymerase chain reaction. Gene ontology and pathway analyses were performed to explore the principal functions of differentially expressed genes. The pathways were involved mainly in immune regulation, intercellular signaling, osteogenic differentiation, protein synthesis, and degradation. Gene signal transduction network, coding-noncoding co-expression network, and competing endogenous RNA expression network were constructed using bioinformatics methods. Then, two miRNAs, miR-17-5p and miR-27b-3p, that could increase the osteogenic differentiation potentials of ligament fibroblasts were identified. Finally, differentially expressed, five lncRNAs, four miRNAs, and five mRNAs were validated using quantitative real-time polymerase chain reaction. These results suggested that mRNAs, lncRNAs, and microRNAs were involved in AS pathogenesis. The findings might help characterize the pathogenesis of AS and provide novel therapeutic targets for patients with AS in the future.

In current study, we investigated the anti-tumor effect of luteolin in human ESCC cell lines in vitro and in vivo and tried to explore the potential mechanisms. Results from flow cytometry showed that luteolin could induce apoptosis and caspase-3 activation and induce cell cycle arrest at G2/M phase in a dose- and time-dependent manner in EC1 and KYSE450 cells. JC-1 test results showed that membrane potential of mitochondria after luteolin treatment was down-regulated and this was an indicator for intrinsic apoptosis. Western Blot results showed the expression of cell cycle regulatory protein p21 and p53 increased and three apoptosis related proteins that participate in mitochondrial apoptotic pathway, namely, Bim, CYT-c and cPARP, also increased in luteolin treated cells compared with control groups. We further confirmed that luteolin could significantly inhibit the growth of ESCC tumors in xenograft mouse models and no evidence of systemic toxicity was observed. Our results suggest that luteolin can induce cell apoptosis and cell cycle arrest in G2/M phase through mitochondrial pathway in EC1 and KYSE450 cell lines and proper utilization of luteolin might be a practical approach in ESCC chemotherapy.

Gastric cancer (GC) is the second most common cause of cancer-related death with limited serum biomarkers for diagnosis and prognosis. Netrin-4 (Ntn4) is a laminin-related secreted molecule found to regulate tumor progression and metastasis. However, it is completely unknown whether Ntn4 has roles in GC development. Here, we first reported Ntn4 knockdown significantly suppressed cell proliferation and motility, while overexpression or addition of exogenous Ntn4 reversed these effects. In addition, Ntn4 receptor, neogenin (Neo) was also found highly expressed in GC cells and mediated the Ntn4-induced cell proliferation and invasion. Moreover, Ntn4 or Neo silencing decreased the phosphorylation of Stat3, ERK, Akt and p38, indicating multi-oncogenic pathways (Jak/Stat, PI3K/Akt, and ERK/MAPK) were involved in Ntn4-induced effects on the GC cells. Importantly, Ntn4 level was significantly increased in 82 tumor tissues (p = 0.001) and 52 serum samples (p < 0.0001) from GC patients and positively correlated with Neo expression (p = 0.003). Ntn4 expression was negatively correlated with the survival period (p = 0.038), and positively associated with the severity of pathological stages of the tumors (p = 0.008). Taken together, Ntn4 promoted the proliferation and motility of GC cells which was mediated by its receptor Neo and through further activation of multi-oncogenic pathways. Elevated Ntn4 was detected in both tumor tissues and serum samples of GC patients and suggested a relatively poor survival, indicating Ntn4 may be used as a potential non-invasive biomarker for diagnosis and prognosis of GC.

Pulmonary fibrosis (PF) associated with chronic sarcoidosis remains poorly understood, and no experimental model is currently available for this condition. Previous studies have shown that Propionibacterium acnes (PA) was associated with sarcoidosis and induced granuloma formation in mice. Here, we investigated whether repeated challenge with PA induces persistent inflammation leading to sarcoidosis followed by PF in mice. Specifically, C57BL/6 mice were inoculated intraperitoneally and subjected to intratracheal challenge with PA, and then were booster-challenged with either PA or phosphate-buffered saline on day 28. Inflammation, granulomata, and features of fibrosis were evaluated every 7 days until day 70. Complete remission of lung granulomata was apparent on day 42 in the sarcoid-remission group. However, granulomata was present from days 21 to 70 in mice that received PA boosting. Inflammatory cell counts and Th1 cytokine levels in lung lavage fluids were elevated up to day 70. Furthermore, fibrotic changes in the lungs were observed around granulomatous and peribronchovascular regions after PA boosting. Taken together, these findings suggest that development of PF following sarcoidosis may result from continuous PA infection and inflammation. Repeated boosting with PA to induce PF might be a useful model for future studies of sarcoidosis-associated PF.

The molecular pathways that contribute to the proliferation and drug response of cancer cells are highly complex and currently insufficiently characterized. We have identified a previously unknown microRNA-based mechanism that provides cancer cells means to stimulate tumorigenesis via increased genomic instability and, at the same time, evade the action of clinically utilized microtubule drugs. We demonstrate miR-493-3p to be a novel negative regulator of mitotic arrest deficient-2 (MAD2), an essential component of the spindle assembly checkpoint that monitors the fidelity of chromosome segregation. The microRNA targets the 3' UTR of Mad2 mRNA thereby preventing translation of the Mad2 protein. In cancer cells, overexpression of miR-493-3p induced a premature mitotic exit that led to increased frequency of aneuploidy and cellular senescence in the progeny cells. Importantly, excess of the miR-493-3p conferred resistance of cancer cells to microtubule drugs. In human neoplasms, miR-493-3p and Mad2 expression alterations correlated with advanced ovarian cancer forms and high miR-493-3p levels were associated with reduced survival of ovarian and breast cancer patients with aggressive tumors, especially in the paclitaxel therapy arm. Our results suggest that intratumoral profiling of miR-493-3p and Mad2 levels can have diagnostic value in predicting the efficacy of taxane chemotherapy.

Recent reports showed that regulator of Cullins-1 (ROC1) play an important role in tumor progression in a tumor-specific manner. However, the role and mechanism of ROC1 in esophageal cancer remains elusive. Here we demonstrated that ROC1 was overexpressed in esophageal squamous cell carcinomas, which was positive associated with poor prognosis of esophageal cancer patients. ROC1 knockdown significantly inhibited the growth of esophageal cancer cells in vitro and in vivo. Mechanistically, ROC1 silencing induced G2 cell cycle arrest and triggered apoptosis by accumulating the pro-apoptotic protein NOXA. Consistently, the downregulation of NOXA expression via siRNA substantially attenuated apoptosis induced by ROC1 silencing. These findings suggest that ROC1 is an appealing drug target for esophageal cancer.

Epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF-1R) both overexpressed on non-small cell lung cancer (NSCLC) and are known cooperatively to promote tumor progression and drug resistance. This study was to construct a novel bispecific fusion protein EGF-IGF-LDP-AE consisting of EGFR and IGF-IR specific ligands (EGF and IGF-1) and lidamycin, an enediyne antibiotic with potent antitumor activity, and investigate its antitumor efficacy against NSCLC. Binding and internalization assays showed that EGF-IGF-LDP protein could bind to NSCLC cells with high affinity and then internalized into cells with higher efficiency than that of monospecific proteins. In vitro, the enediyne-energized analogue of bispecific fusion protein (EGF-IGF-LDP-AE) displayed extremely potent cytotoxicity to NSCLC cell lines with IC50<10-11 mol/L. Moreover, the bispecific protein EGF-IGF-LDP-AE was more cytotoxic than monospecific proteins (EGF-LDP-AE and LDP-IGF-AE) and lidamycin. In vivo, EGF-IGF-LDP-AE markedly inhibited the growth of A549 xenografts, and the efficacy was more potent than that of lidamycin and monospecific counterparts. EGF-IGF-LDP-AE caused significant cell cycle arrest and it also induced cell apoptosis in a dosage-dependent manner. Pretreatment with EGF-IGF-LDP-AE inhibited EGF-, IGF-stimulated EGFR and IGF-1R phosphorylation, and blocked two main downstream signaling molecules AKT and ERK activation. These data suggested that EGF-LDP-IGF-AE protein would be a promising targeted agent for NSCLC patients with EGFR and/or IGF-1R overexpression.

Multiple sclerosis (MS) is an autoimmune disease characterized by the dysregulated immune response including innate and adaptive immune responses. Increasing evidence has proven the importance of epigenetic modification in the progression of MS. Recent studies revealed that low-dose decitabine (Dec, 5-Aza-2'-deoxycytidine), which incorporates into replicating DNA and inhibits DNA methylation, could prevent experimental autoimmune encephalomyelitis (EAE) development by increasing the number of regulatory T cells (Tregs). Here, we showed that higher-dose decitabine relative to previous studies could also distinctly protect mice from EAE and allogeneic cardiac transplantation. Mechanistic studies revealed decitabine suppressed innate responses in EAE mice through inhibiting the activation of microglia and monocyte-derived macrophages that contributed to reduce the severity of EAE. Furthermore, differentiation of naïve CD4+ T cells into Th1 and Th17 cells was significantly suppressed by decitabine in vivo and in vitro. Though in vitro studies showed decitabine could induce Treg differentiation, there was no obvious change in the percentage of Tregs in Dec-treated EAE mice. Most importantly, we found that T cell proliferation was potently inhibited in vivo and in vitro by higher-dose decitabine through increased gene expression of the DNA dioxygenase TET2 which facilitated the expression of several cell cycle inhibitors. Collectively, our study provides novel mechanistic insights of using the epigenetic modifying agents in the management of both allo- and auto-immune responses.

Malignant epithelial ovarian cancer (EOC) spheroids high frequently are detected in the malignant ascites of the patients with the extensive peritoneal metastasis of ovarian cancer, which represent a significant obstacle to efficacious treatment. Clinical data also suggested that EOC spheroids play a putative role in the development of chemoresistance. Since standard surgery and conventional chemotherapy is the only available treatment, there is an urgent need to identify a more effective therapeutic strategy. Recent studies demonstrated that curcumin exerts an anticancer effect in a variety of human cancers including ovarian cancer. This study evaluates anti-peritoneal metastasis and chemoresistance of curcumin related to the EOC spheroids. In this study, we confirm that the high invasive EOC cells forming the spheroids express a high level of a cancer stem cell (CSC) marker, aldehyde dehydrogenase 1 family member A1 (ALDH1A1), which was significantly down-regulated by curcumin treatment. Curcumin treatment markedly enhances the sensitivity of EOC spheroids to cisplatin in a dose-dependent manner. Our experiments provided evidence that curcumin could abolish the sphere-forming capacity of EOC cells in a dose-dependent manner. Moreover, curcumin substantially suppressed the growth of the pre-existed EOC spheroids, inhibited the adhesion of EOC spheroids to ECM as well as the invasion of EOC spheroids to the mesothelial monolayers. We propose to re-purpose curcumin as anti-metastatic and chemoresistant agent for EOC management in combination with conventional regimen. Further preclinical studies are necessary to validate the anti-cancer effect of curcumin in patients with EOC.

To assess the associations of P16INK4a methylation status with low-grade squamous intra-epithelial lesion (LSIL), high-grade squamous intra-epithelial lesion (HSIL), cervical cancer (CC) and their clinicopathological features, a meta-analysis with 29 eligible studies was conducted. Pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated to assess the strength of the associations. Heterogeneity, sensitivity of pooled results and publication bias were also evaluated. Overall, there was an increasing trend of P16INK4a hypermethylation rates among LSIL (21.4%), HSIL (30.9%) and CC (35.0%) specimens. P16INK4a hypermethylation was significantly associated with the increased risk of LSIL, HSIL and CC, with the pooled ORs of 3.26 (95% CI: 1.86-5.71), 5.80 (95% CI: 3.80-8.84) and 12.17 (95% CI: 5.86-25.27), respectively. A significant association was also found between P16INK4a hypermethylation and smoking habit (OR = 3.88, 95% CI: 2.13-7.08). Taken together, meta-analysis results support P16INK4a hypermethylation as an epigenetic marker for the progression of cervical carcinogenesis.

Focal adhesion kinase (FAK) has been implicated in tumorigenesis in various malignancies. We sought to examine the expression patterns of FAK and the activated form, phosphorylated FAK (pFAK), in human osteosarcoma and to investigate the correlation of FAK expression with clinicopathologic parameters and prognosis. In addition, the functional consequence of manipulating the FAK protein level was investigated in human osteosarcoma cell lines. Immunohistochemical staining was used to detect FAK and pFAK in pathologic archived materials from 113 patients with primary osteosarcoma. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognoses. The role of FAK in the cytological behavior of MG63 and 143B human osteosarcoma cell lines was studied via FAK protein knock down with siRNA. Cell proliferation, migration, invasiveness and apoptosis were assessed using the CCK8, Transwell and Annexin V/PI staining methods. Both FAK and pFAK were overexpressed in osteosarcoma. There were significant differences in overall survival between the FAK-/pFAK- and FAK+/pFAK- groups (P = 0.016), the FAK+/pFAK- and FAK+/pFAK+ groups (P = 0.012) and the FAK-/pFAK- and FAK+/pFAK+ groups (P < 0.001). There were similar differences in metastasis-free survival between groups. The Cox proportional hazards analysis showed that the FAK expression profile was an independent indicator of both overall and metastasis-free survival. SiRNA-based knockdown of FAK not only dramatically reduced the migration and invasion of MG63 and 143B cells, but also had a distinct effect on osteosarcoma cell proliferation and apoptosis. These results collectively suggest that FAK overexpression and phosphorylation might predict more aggressive biologic behavior in osteosarcoma and may be an independent predictor of poor prognosis.