RPL18 has emerged as a regulator of tumor behavior beyond its canonical role in protein synthesis. Here, we show that RPL18 enhances melanoma progression and chemoresistance by engaging both intrinsic signaling and the tumor microenvironment. Using melanoma cell lines, patient-derived organoids, and xenograft models, we demonstrate that RPL18 stabilizes BTF3 mRNA, leading to increased BTF3 expression and activation of STAT3 signaling. This pathway promotes melanoma cell proliferation, migration, and resistance to temozolomide. In parallel, RPL18-driven STAT3 activation increases transforming growth factor β (TGF-β) secretion, which induces M2 macrophage polarization and fosters an immunosuppressive microenvironment. Pharmacologic inhibition of STAT3 suppresses RPL18-dependent oncogenic phenotypes and restores temozolomide sensitivity in vitro and in vivo. These findings establish RPL18 as a key coordinator of melanoma progression by linking tumor-intrinsic pathways with microenvironmental regulation. Targeting the RPL18-BTF3-STAT3 axis may improve therapeutic responses in melanoma and other cancers with heightened STAT3 activity.

Imatinib is highly effective in the treatment of chronic myelogenous leukemia (CML), but the primary and acquired imatinib resistance remains the big hurdle. Molecular mechanisms for CML resistance to tyrosine kinase inhibitors, beyond point mutations in BCR-ABL kinase domain, still need to be addressed. Here, we demonstrated that thioredoxin-interacting protein (TXNIP) is a novel BCR-ABL target gene. Suppression of TXNIP was responsible for BCR-ABL triggered glucose metabolic reprogramming and mitochondrial homeostasis. Mechanistically, Miz-1/P300 complex transactivates TXNIP through the recognition of TXNIP core promoter region, responding to the c-Myc suppression by either imatinib or BCR-ABL knockdown. TXNIP restoration sensitizes CML cells to imatinib treatment and compromises imatinib resistant CML cell survival, predominantly through the blockage of both glycolysis and glucose oxidation which results in the mitochondrial dysfunction and ATP production. In particular, TXNIP suppresses expressions of the key glycolytic enzyme, hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA), potentially through Fbw7-dependent c-Myc degradation. In accordance, BCR-ABL suppression of TXNIP provided a novel survival pathway for the transformation of mouse bone marrow cells. Knockout of TXNIP accelerated BCR-ABL transformation, whereas TXNIP overexpression suppressed this transformation. Combination of drug inducing TXNIP expression with imatinib synergistically kills CML cells from patients and further extends the survival of CML mice. Thus, the activation of TXNIP represents an effective strategy for CML treatment to overcome resistance.

Background: Drug resistance is one of the biggest challenges in cancer therapy. temozolomide (TMZ) represents the most important chemotherapeutic option for glioma treatment. However, the therapeutic efficacy of TMZ remains very limited due to its frequent resistance in glioma, and the underlying mechanisms were not fully addressed. Herein, we demonstrate that the elevated expression of CD147 contributes to TMZ resistance in glioma cells, potentially through the post-translational regulation of Nrf2 expression. Methods: Cell-based assays of CD147 triggered drug resistance were performed through Edu-incorporation assay, CCK8 assay, TUNEL staining assay and flow cytometric assay. Luciferase reporter assay, protein stability related assays, co-immunoprecipitation assay were used to determine CD147 induction of Nrf2 expression through β-TrCP dependent ubiquitin system. Finally, the effect of the CD147/Nrf2 signaling on glioma progression and TMZ resistance were evaluated by functional experiments and clinical samples. Results: Based on the analysis of clinical glioma tissues, CD147 is highly expressed in glioma tissues and positively associated with tumor malignancy. Suppression of CD147 expression increased the inhibitory effect of TMZ on cell survival in both U251 and T98G cells, whereas the gain of CD147 function blocked TMZ-induced ROS production and cell death. Mechanistic study indicates that CD147 inhibited GSK3β/β-TrCP-dependent Nrf2 degradation by promoting Akt activation, and subsequently increased Nrf2-mediated anti-oxidant gene expressions. Supporting the biological significance, the reciprocal relationship between CD147 and Nrf2 was observed in glioma tissues, and associated with patient outcome. Conclusions: Our data provide the first evidence that glioma resistance to TMZ is potentially due to the activation of CD147/Nrf2 axis. CD147 promotes Nrf2 stability through the suppression of GSK3β/β-TrCP dependent Nrf2 protein degradation, which results in the ablation of TMZ induced ROS production. As such, we point out that targeting CD147/Nrf2 axis may provide a new strategy for the treatment of TMZ resistant gliomas.

Background Poorly differentiated colorectal cancers are more aggressive. Metabolism reprogramming is a significant hallmark in cancer, and aerobic glycolysis is common. However, how cancer cells reprogramming glucose metabolism contributes to cell differentiation was largely unknown. Previous studies have reported that tumor suppressor NDRG2 could promote colorectal cancers differentiation. Aims This study aims to demonstrate that NDRG2 promotes the differentiation of colorectal cancers, potentially through the inhibition of aerobic glycolysis via TXNIP induction. Methods Western blotting, qRT-PCR and immunohistochemical staining were used to detect the expression of related molecules. MTT assay was used to reflect cell viability and proliferation. Immunofluorescent assay was performed to identify the expression and distribution of molecules. Luciferase analysis and CHIP assays were used to investigate the mechanism. Bioinformatic analysis was performed to predict the relevance. Results In colorectal cancers, NDRG2 could inhibit cell proliferation, reduce glucose uptake and decrease expression of key glycolysis enzymes. Upregulated NDRG2 is associated with differentiated cancer. However, deletion of TXNIP, a classic glucose metabolism inhibitor, could obviously alter the function of NDRG2 in differentiation, glucose uptake, expression of key glycolysis enzymes and proliferation. Mechanistically, high glucose flux promotes the activity of TXNIP promoter. And NDRG2 promotes the occupancy of transcription factor Mondo A on TXNIP promoter, predominantly through the suppression of c-myc, which could complete with Mondo A binding to TXNIP promoter. In clinical samples, high expression of TXNIP indicates good prognosis and outcome. Conclusions NDRG2-dependent induction of TXNIP is critical for the aerobic glycolysis during colorectal cancers differentiation.

BACKGROUND:Paracellular barriers play an important role in the pathogenesis of Inflammatory bowel disease (IBD) and maintain gut homeostasis. N-myc downstream-regulated gene 2 (NDRG2) has been reported to be a tumour suppressor gene and to inhibit colorectal cancer metastasis. However, whether NDRG2 affects colitis initiation and colitis-associated colorectal cancer is unclear.METHODS:Intestine-specific Ndrg2 deficiency mice (Ndrg2ΔIEC) were subjected to DSS- or TNBS-induced colitis, and AOM-DSS-induced colitis-associated tumour. HT29 cells, Caco2 cells, primary intestinal epithelial cells (IECs) from Ndrg2ΔIEC mice, mouse embryo fibroblasts (MEFs) from systemic Ndrg2 knockout mice, HEK293 cells and human UC and DC specimens were used to investigate NDRG2 function in colitis and colitis-associated tumour.FINDINGS:Ndrg2 loss led to adherens junction (AJ) structure destruction via E-cadherin expression attenuation, resulting in diminished epithelial barrier function and increased intestinal epithelial permeability. Mechanistically, NDRG2 enhanced the interaction of E3 ligase FBXO11 with Snail, the repressor of E-cadherin, to promote Snail degradation by ubiquitination and maintained E-cadherin expression. In human ulcerative colitis patients, reduced NDRG2 expression is positively correlated with severe inflammation.INTERPRETATION:These findings demonstrate that NDRG2 is an essential colonic epithelial barrier regulator and plays an important role in gut homeostasis maintenance and colitis-associated tumour development.FUNDING:National Natural Science Foundation of China (No. 81770523, 31571437, 81672751), Creative Research Groups of China (No. 81421003), State Key Laboratory of Cancer Biology Project (CBSKL2019ZZ11, CBSKL201406, CBSKL2017Z08 and CBSKL2017Z11), Fund for Distinguished Young Scholars of ShaanXi province (2019JC-22).

BRAFV600E mutation is frequently observed in melanoma, and contributes to tumor malignancy. Despite inhibition of BRAF causes a profound cell growth inhibition and a strong clinical benefit in BRAFV600E melanoma, acquired drug resistance is still the major hurdle. In this study, we demonstrate that BRAFV600E drives cell growth and glycolysis in melanoma cells but does so by a previously unappreciated mechanism that involves direct induction of Skp2. Skp2 is highly expressed in melanoma tissues and particularly in tissues with BRAFV600E mutation. The inhibition of BRAFV600E by either siRNA or inhibitor vemurafenib suppressed Skp2 expression and cell growth. Mechanistic study shows that BRAFV600E suppression of Skp2 is dependent on c-Myc transcription factor via specifically bounding to the E-box region on SKP2 promoter. Further, the overexpression of Skp2 resulted in a markedly increase in cell growth, cell cycle progression and glycolysis which were repressed by BRAFV600E inhibition. Supporting the biological significance, Skp2 is specifically correlated with poor patient outcome in BRAFV600E but did not in BRAFWT melanomas. Thus, as a downstream target of BRAFV600E, Skp2 is critical for responses to BRAF inhibition, indicating targeting Skp2 might be a promising strategy for the treatment of BRAFi resistant melanomas.

OBJECTIVE:This study was undertaken to uncover the pathophysiologic role of discoidin domain receptor 2 (DDR-2), a putative fibrillar collagen receptor, in inflammation promotion and joint destruction in rheumatoid arthritis (RA).METHODS:In synovial tissue from patients with RA and from mice with collagen antibody-induced arthritis (CAIA) (using Ddr2-/- and DBA/1 mice), gene and protein expression levels of DDR-2, interleukin-15 (IL-15), and Dkk-1 were measured by quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry. Gene knockdown of DDR2 in human RA fibroblast-like synoviocytes (FLS) was conducted via small interfering RNA. Interaction between the long noncoding RNA H19 and microRNA 103a (miR-103a) was assessed in RA FLS using RNA pulldown assays. Cellular localization of H19 was examined using fluorescence in situ hybridization assays. Chromatin immunoprecipitation and dual luciferase reporter assays were applied to verify H19 transcriptional and posttranscriptional regulation by miR-103a.RESULTS:DDR2 messenger RNA (mRNA) expression was significantly associated with the levels of IL-15 and Dkk-1 mRNA in the synovial tissue of RA patients (r2 = 0.2022-0.3293, all P < 0.05; n = 33) and with the serum levels of IL-15 and Dkk-1 in mice with CAIA (P < 0.05). In human RA FLS, activated DDR-2 induced the expression of H19 through c-Myc. Moreover, H19 directly interacted with and promoted the degradation of miR-103a.CONCLUSION:These results indicate a novel role for activated DDR-2 in RA FLS, showing that DDR-2 is responsible for regulating the expression of IL-15 and Dkk-1 in RA FLS and is involved in the promotion of inflammation and joint destruction during pathophysiologic development of RA. Moreover, DDR-2 inhibition, acting through the H19-miR-103a axis, leads to reductions in the inflammatory reaction and severity of joint destruction in mice with CAIA, suggesting that inhibition of DDR-2 may be a potential therapeutic strategy for RA.

Background: Metastasis is the most common cause of lethal outcome in various types of cancers.Although the cell proliferation related metabolism rewiring has been well characterized, less is known about the association of metabolic changes with tumor metastasis.Herein, we demonstrate that metastatic tumor obtained a mesenchymal phenotype, which is obtained by the loss of tumor suppressor NDRG2 triggered metabolic switch to glutamine metabolism.Methods: mRNA-seq and gene expression profile analysis were performed to define the differential gene expressions in primary MEC1 and metastatic MC3 cells and the downstream pathways of NDRG2.NDRG2 regulation of Fbw7-dependent c-Myc stability were determined by immunoprecipitation and protein half-life assay.Luciferase reporter and ChIP assays were used to determine the roles of Akt and c-Myc in mediating NDRG2-dependent regulation of ASCT2 in in both tumor and NDRG2-knockout MEF cells.Finally, the effect of the NDRG2/Akt/c-Myc/ASCT2 signaling on glutaminolysis and tumor metastasis were evaluated by functional experiments and clinical samples.Results: Based on the gene expression profile analysis, we identified metastatic tumor cells acquired the mesenchymal-like characteristics and displayed the increased dependency on glutamine utilization.Further, the gain of NDRG2 function blocked epithelial-mesenchymal transition (EMT) and glutaminolysis, potentially through suppression of glutamine transporter ASCT2 expression.The ASCT2 restoration reversed NDRG2 inhibitory effect on EMT program and tumor metastasis.Mechanistic study indicates that NDRG2 promoted Fbw7-dependent c-Myc degradation by inhibiting Akt activation, and subsequently decreased c-Myc-mediated ASCT2 transcription, in both tumor and NDRG2-knockout MEF cells.Supporting the biological significance, the reciprocal relationship between NDRG2 and ASCT2 were observed in multiple types of tumor tissues, and associated with tumor malignancy.Conclusions: NDRG2-dependent repression of ASCT2 presumably is the predominant route by which NDRG2 rewires glutaminolysis and blocks metastatic tumor survival.Targeting glutaminolytic pathway may provide a new strategy for the treatment of metastatic tumors.

In contrast to what is known about the complicated roles of Notch signalling in human malignancies, the direct target genes of Notch signalling are still unclear. Recently, long noncoding RNAs (lncRNAs) have been found to play various roles in the post-transcriptional regulation of gene expression. In the present study, we investigated the potential role of the Notch-induced lncRNA LUNAR1 in colorectal cancer (CRC). We recruited 196 cases of clinical CRC specimens and investigated LUNAR1 levels in these specimens. The associations of LUNAR1 with tumour aggressiveness and clinical outcomes were evaluated. Moreover, the impact of LUNAR1 on the malignant behaviour of tumour cells was tested in cell lines. Significantly increased expression of LUNAR1 in clinical CRC specimens was detected compared with that in matching normal tissues. LUNAR1 expression in CRC was found to be associated with the tumour aggressiveness, disease-free survival and overall survival of patients. The downregulation of LUNAR1 in SW620 cells inhibited cell proliferation, migration, invasion and tumour growth while inducing apoptosis. Moreover, the inhibition of LUNAR1 can significantly suppress IGF1 signalling in CRC. These results indicated that LUNAR1 was increased in CRC and might promote tumour progression. Thus, LUNAR1 may constitute a promising prognostic marker for the clinical management of CRC.

Background: Renal interstitial fibrosis is a common pathway of chronic kidney disease to end-stage renal disease, which is characterized by an imbalance between the synthesis and degradation of the collagen-rich extracellular matrix (ECM). While, discoidin domain receptor 2 (DDR2) can be activated when it binds to some types of collagen. Therefore, we hypothesized that DDR2 may be a major player in renal interstitial fibrosis. Methods: Renal histologic analysis, real-time PCR analyses and hydroxyproline assay were performed in DDR2-deficient mice and wild-type mice after unilateral ureteral obstruction; C57 mice were randomly divided into sham operation group (Sham group, n = 4), renal interstitial fibrosis model group (UUO group, n = 4), and calcium dobesilate treatment group (CDT group, n = 4), preparation of renal interstitial fibrosis model by unilateral ureteral obstruction (UUO), CDT Group was treated with calcium dobesilate orally, Sham group and UUO group were given double distilled water, HE staining, Masson staining, real-time quantitative PCR were detected after 14 days of UUO in mice to observe the renal interstitial fibrosis degree. Results: DDR2 expression was dramatically increased in the obstructed kidney; In contrast to wild-type mice that developed severe interstitial fibrosis, the DDR2-deficient mice displayed only moderate fibrotic changes; Compared with the UUO group, the degree of renal interstitial fibrosis in CDT group was relieved after operation 14 day. Conclusion: DDR2 might play an important role in the development of RIF; Calcium dobesilate can affect the expression of DDR2 and improve the renal interstitial fibrosis in mice.

BACKGROUND:Myocardial infarction (MI) is a common cause of mortality in people. Mesenchymal stem cell (MSC) has been shown to exert therapeutic potential to treat myocardial infarction (MI). However, in patients with diabetes, the diabetic environment affected MSCs activity and could impair the efficacy of treatment. Interleukin-10 (IL-10) has been shown to attenuate MI by suppressing inflammation. In current study, the combination of MSC transplantation with IL-10 was evaluated in a diabetic mice model with MI.METHODS:We engineered bone marrow derived MSCs (BM-MSCs) to overexpress IL-10 by using CRISPR activation. We established the diabetic mice model with MI and monitored the IL-10 expression after BM-MSCs transplantation. We also evaluated the effects of BM-MSCs transplantation on inflammatory response, cell apoptosis, cardiac function and angiogenesis.RESULTS:CRISPR activation system enabled overexpression of IL-10 in BM-MSCs. Transplantation of BM-MSCs overexpressing IL-10 resulted in IL-10 expression in heart after transplantation. Transplantation of BM-MSCs overexpressing IL-10 inhibited inflammatory cell infiltration and pro-inflammatory cytokines production, improved cardiac functional recovery, alleviated cardiac injury, decreased apoptosis of cardiac cells and increased angiogenesis.CONCLUSION:In summary, we have demonstrated the therapeutic potential of IL-10 overexpressed BM-MSCs in the treatment of MI in diabetic mice.

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease that primarily manifests as persistent synovitis and progressive joint destruction. Imatinib exhibited a therapeutic effect in murine collagen-induced arthritis (CIA) via selective inhibition tyrosine kinases. The second-generation tyrosine kinase inhibitor dasatinib exhibits more durable hematological and cytogenetic effects and more potency compared to imatinib. However, the effect of dasatinib on CIA is poorly understood. The present study investigated the treatment effect of dasatinib on autoimmune arthritis. We demonstrated that dasatinib alleviated arthritis symptoms and histopathological destruction in CIA mice. Dasatinib treatment inhibited the production of proinflammatory cytokines including IL-1β, TNF-α, and IL-6, and promoted the production of the anti-inflammatory cytokine IL-10. Dasatinib treatment also suppressed the expression of anti-mouse CII antibodies including total IgG, IgG1, IgG2, and IgG2b, in CIA mice. We further demonstrated that dasatinib inhibited the migration and proliferation of fibroblast-like synoviocytes (FLS) from RA patients and promoted FLS apoptosis. The mRNA expression of MMP13, VEGF, FGF, and DKK1 was down-regulated in FLS treated with dasatinib. Our findings suggest that dasatinib exhibited treatment effects on CIA mice and that FLS are an important target cell of dasatinib treatment in autoimmune arthritis.

The most typical structural feature of human interstitial lung diseases (ILDs) is the accumulation of vast amounts of collagens within the lung interstitium. The membrane receptors that are responsible for recognising collagens and then transducing signals into the cells include four members of the integrin family (α1β1, α2β1, α10β1 and α11β1) and two members of the discoidin domain receptor family (DDR1 and DDR2). However, it remains unknown whether these six collagen receptors similarly contribute to the pathogenesis of fibrotic lung diseases. Quantitative real-time PCR (qPCR) was utilised to assess the mRNA expression of the genes studied. Immunoblot experiments were performed to analyse the protein abundance and kinase activity of the gene products. The tissue location was determined by immunohistochemical staining. qPCR data showed that DDR2 mRNA displays the most dramatic difference between idiopathic pulmonary fibrosis (IPF) patients and healthy groups. The outstanding increases in DDR2 proteins were also observed in some other types of ILD besides IPF. DDR2-expressing cells in ILD tissue sections were found to exhibit spindle or fibroblastic shapes. Our investigation suggests that DDR2 might represent a major cell surface protein that mediates collagen-induced cellular effects in human ILD and, hence, is suitable for their diagnosis and therapy.

Notch signal has complex roles in human malignancies, which might be attributed to the diversity of Notch receptors. Here, we set out to identify the association of NOTCH4 with colorectal cancer (CRC). In the hospital-based study cohort, we investigated NOTCH4 mRNA levels in primary CRC, as well as its association with clinicopathologic characteristics. Besides, NOTCH4 cDNA and siRNA was transfected into colorectal cancer cell line to elucidate its impact on tumor cell proliferation and migration. Results revealed a statistically significant lower expression of NOTCH4 mRNA in tumor specimens compared with that in control. NOTCH4 level in CRC was found to be related to tumor differentiation, invasion, and node metastasis. Moreover, it was demonstrated that NOTCH4 mRNA level could be an independent prognostic factor for both disease-free and overall survival of CRC patients. Overexpression of NOTCH4 in CRC cell lines suppressed tumor cell proliferation, migration, and invasion, while induced apoptosis. In the opposite, the malignant behavior of CRC cells was enhanced by NOTCH4 knockdown. These results demonstrated for the first time that NOTCH4 expression was decreased in CRC, which could determine tumor proliferation, relapse, and prognosis.

Epithelial-mesenchymal transition (EMT) is required for the distant metastasis of tumors. The degree of tumor malignancy increases as EMT progresses. Notably, the biology of tumor cells differs from that of normal cells, with regards to characteristics and energy metabolism mechanisms; abnormal glucose metabolism, excessive accumulation of fatty acids and other metabolic disorders occur in metastatic tumors. Previous studies have confirmed that the regulation of tumor cell metabolism can affect tumor metastasis and some findings have resulted in novel clinical applications. The present review aimed to provide a basis for treatments targeting the tumor EMT process and metabolic reprogramming.

As a novel candidate tumor suppressor, NDRG4 is largely unstudied in human malignancies. In this study, we investigated the protein expression level of NDRG4 in gastric cancer and its association with outcome of patients. In the present study, we recruited 286 patients with gastric cancer and investigated the protein and mRNA expression of NDRG4 in cancer and adjacent normal specimens by immunohistochemistry assay and real-time PCR. The association of NDRG4 level with clinicopathological characteristics was investigated by appropriate statistical analysis. NDRG4 overexpression and knockdown cell lines were established in order to detect its impact on proliferation and apoptosis. Significant decreased protein and mRNA expression of NDRG4 was found in gastric cancer, compared with adjacent normal specimens. Besides, it was found that NDRG4 protein expression in gastric cancer was significantly associated with tumor differentiation, invasion, metastasis, and stage. Patients with tumors of decreased NDRG4 level were more likely to have unfavorable disease-free and overall survival, in both univariate and multivariate analysis. In addition, overexpression of NDRG4 suppressed cell proliferation of gastric cancer cells in vitro; conversely, the proliferation of gastric cancer cells were enhanced by knockdown of NDRG4. These results proved for the first time that NDRG4 could be a potential tumor suppressor and prognostic marker of gastric cancer.

Idiopathic pulmonary fibrosis (IPF) is a lethal human disease with short survival time and few treatment options. Herein, we demonstrated that discoidin domain receptor 2 (DDR2), a receptor tyrosine kinase that predominantly transduces signals from fibrillar collagens, plays a critical role in the induction of fibrosis and angiogenesis in the lung. In vitro cell studies showed that DDR2 can synergize the actions of both transforming growth factor (TGF)-β and fibrillar collagen to stimulate lung fibroblasts to undergo myofibroblastic changes and vascular endothelial growth factor (VEGF) expression. In addition, we confirmed that late treatment of the injured mice with specific siRNA against DDR2 or its kinase inhibitor exhibited therapeutic efficacy against lung fibrosis. Thus, this study not only elucidated novel mechanisms by which DDR2 controls the development of pulmonary fibrosis, but also provided candidate target for the intervention of this stubborn disease.

OBJECTIVE:To understand which lysine (K) residue in ubiquitin (Ub) is used to form a poly-Ubs chain on discoidin domain receptor 2 (DDR2).METHODS:The constructs encoding human DDR2 and Cbl-b were transiently transfected into HEK293T cells together with the Ub mutants with lysine mutation at different sites, and the transfected cells were stimulated with collagens in order to induce the activation of DDR2. Immunoprecipitation was performed to isolate DDR2, and the immunoprecipitates were then subjected to immunoblot analysis for the conjugation of DDR2 with Ub.RESULTS:Ub K27-only mutant displayed the strongest poly-Ub chain formation on DDR2, while Ub K33-only mutant exhibited weak ability to be conjugated with DDR2. These findings were further confirmed by Ub K27R and K33R mutants, which reduced DDR2 polyubiquitination.CONCLUSION:DDR2 is linked to a polyUb chain predominantly through K27 conjugation and slightly through K33.

Testis-specific gene 13 (TSGA13) is abundantly expressed in testis. As previous studies of TSGA13 expression pattern have all been based on mRNA analysis, it is imperative to investigate its actual protein expression. Here, we first examined TSGA13 gene tree and protein homology among species, and found that TSGA13 is relatively well conserved. Next, we detected its protein expression in normal human tissues as well as in a limited number of malignant tumors by immunohistochemistry (IHC). It was demonstrated that, in addition to testis, high expression of TSGA13 could also be observed in multiple normal tissues, including stomach, larynx, spleen, bladder, tonsil, liver and thyroid. Notably, most types of human carcinoma tissues displayed reduced expression of TSGA13 rather than their adjacent normal tissues except glioblastoma and lung cancer. Hence, the data from the current study strongly suggest the association between TSGA13 and tumor malignancy.