Long-term response to sintilimab, bevacizumab and chemotherapy in heavily pretreated microsatellite stable colon cancer.

Most advanced colorectal cancer patients with proficient DNA mismatch repair or microsatellite stability (MSS) are insensitive to immune checkpoint inhibitor therapy. This report describes a heavily pretreated refractory colon adenocarcinoma patient with MSS. After experiencing four lines of treatment, the patient received the fifth-line therapy with the combined sintilimab, bevacizumab and chemotherapy. She achieved a long-term clinical outcome. The patient's progression-free survival after the fifth-line therapy was approximately 9.3 months, and her overall survival was approximately 57 months. To the best of our knowledge, this case represents the first report of durable clinical benefit from combination of an immune checkpoint inhibitor, bevacizumab and chemotherapy in a heavily pretreated patient with refractory metastatic colon adenocarcinoma with MSS.

To date, little information is available on the efficacy of combination of immunotherapy, antiangiogenic therapy and chemotherapy in heavily pretreated refractory colon cancer patients with microsatellite stability (MSS). Here, we describe a heavily pretreated refractory colon adenocarcinoma patient with MSS. After experiencing four lines of prior treatment, the patient received the fifth-line therapy with the combined immunotherapy, an antiangiogenetic inhibitor and chemotherapy. She achieved a durable clinical outcome. To our knowledge, this case is the first report of successful treatment of a heavily pretreated refractory metastatic colon adenocarcinoma patient with MSS receiving the combined immunotherapy, antiangiogenic therapy and chemotherapy.

Long-term response to camrelizumab in a pretreated metastatic mixed testicular germ-cell tumor patient with co-mutations in DNA damage-repair genes.

Little information is available regarding the therapeutic efficacy of immune checkpoint inhibitors and the prediction of DNA damage-repair (DDR) genes in mixed testicular germ-cell tumors (TGCTs). Here we report a pretreated patient with metastatic mixed TGCT harboring variations of three important DDR genes - BRCA2, MSH6 and PMS2 - identified by next-generation sequencing using plasma-based circulating tumor DNA. He obtained stable clinical benefit from PD-1 blockade. At the latest follow-up, he had a progression-free survival of more than 28 months and had survived 6.75 years since diagnosis. To our knowledge, this case is the first report of long-term clinical outcome obtained from immune checkpoint inhibitor therapy in a pretreated patient with mixed metastatic TGCT harboring co-mutations in DDR genes.

Complete and durable response to crizotinib in a patient with malignant pleural mesothelioma harboring CD74-ROS1 fusion.

Malignant pleural mesothelioma (MPM) is a rare and deadly malignancy with an extremely poor prognosis. The median overall survival (OS) of this disease is 12-18 months. However, the oncogenic driver mutations of MPM are rarely understood, and the targeted therapy for it is still under investigation. In this report, we describe a case of MPM with CD74-ROS1 fusion who obtains complete and durable response after receiving crizotinib. By the time of submission, the progression-free survival (PFS) with crizotinib has been 6.0 years, and the patient has survived for 7.6 years. Currently, he is still in complete remission (CR). To the best of our knowledge, this case represents the first report of CD74-ROS1 fusion identified in MPM. Meanwhile, it is also the first report of complete and long-term response to crizotinib in a patient with MPM positive for CD74-ROS1 fusion. This case report might contribute to the tumorigenesis and targeted therapy of this deadly disease.

Dramatic response to local radiotherapy in a refractory metastatic mediastinal yolk sac tumor patient harboring a germline BRCA2 frameshift mutation: a case report.

Mediastinal yolk sac tumors (YSTs) are highly aggressive germ cell tumors with an extremely poor prognosis. Radiotherapy plays an important role in the treatment of mediastinal YSTs. To maximize benefit from radiotherapy in patients with mediastinal YSTs, exploring functionally relevant biomarkers is essential. Previous studies have demonstrated that mutations in DNA-damage repair (DDR) genes, including BRCA1/2, potentially enhance sensitivity to radiotherapy in solid tumors. However, DDR-gene mutations, as possible predictive biomarkers for radiotherapy in primary mediastinal YSTs, have not yet been reported. Herein, we report a 29-year-old male patient with a refractory metastatic primary YST involving a germline frameshift mutation in the BRCA2 gene (NM_000059.3: exon11: c.4563_4564delAT: L1522fs). During treatment alternation, the patient was found to respond poorly to chemotherapy with or without an immune checkpoint inhibitor but well to radiotherapy. Finally, the patient achieved approximately 17 months of overall survival. To the best of our knowledge, this case report is the first to describe a remarkable response to local radiotherapy in a patient with a refractory metastatic mediastinal YST involving a DDR-gene mutation (germline BRCA2 frameshift variation). This case report provides insightful clues for precision radiotherapy in clinical practice.

Case report: identification of ERC1-RET fusion in a patient with pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy. Currently, treatment strategies for PDAC are limited because its molecular characteristics have not yet been clarified. Different RET fusions have been reported in diverse solid tumors, especially in non-small cell lung cancer (NSCLC) and papillary thyroid carcinoma (PTC). Multikinase inhibitors (MKIs) such as cabozantinib, vandetanib and lenvatinib, as well as selective inhibitors of RET alterations like selpercatinib (LOXO-292) and pralsetinib (BLU-667) have been approved by the Food and Drug Administration (FDA) for patients with RET fusion-positive tumors, such as thyroid cancer, renal cell, NSCLC, and so on. However, few studies have been reported about the association between RET fusions and PDAC. ERC1-RET fusion is a rare rearrangement. To date, it has only been reported in lung cancer and thyroid cancer. Studies of ERC1-RET fusion in PDAC have not yet been explored. In this study, we reported an ERC1-RET fusion in a 60-year-old female patient with PDAC. To the best of our knowledge, this case was the first report about ERC1-RET fusion in a patient with PDAC. It is a pity that the patient refused targeted therapy for personal reasons. Our study has shed a new light on the companion diagnostics and targeted therapy for the patients with PDAC.

Homozygous deletion of the HLA-B gene as an acquired-resistance mechanism to nivolumab in a patient with lung adenocarcinoma: a case report.

Immune checkpoint inhibitors (ICIs) have greatly improved the treatment of advanced non-small-cell lung cancer, including lung adenocarcinoma (LUAD). Patients treated with ICIs can have long-term clinical outcomes; however, acquired resistance to ICI therapy has been frequently observed. To date, little is known about the underlying mechanisms. In this study, we report the case of a male smoker with metastatic LUAD who initially received multi-line radiotherapy and chemotherapy and achieved stable disease (SD) for almost 10 years. The patient was treated with nivolumab for about 15 months. However, the disease later progressed rapidly. A genetic profile of the patient revealed the homozygous deletion of the human leukocyte antigen (HLA)-B gene, which may have conferred the acquired resistance. Our study is the first to describe the homozygous deletion of the HLA-B gene as an acquired-resistance mechanism to programmed cell death protein 1 (PD-1) blockade in a patient with LUAD. This evidence suggests that tumor cells can selectively lose HLA-A, B, and C to survive under strong immune pressure. This discovery enriches and develops our understanding of the mechanism of drug resistance in ICI therapy in LUAD. However, further investigations are urgently needed to be conducted to determine how this resistance can be overcome.

Identification of a Novel Immune-Related CpG Methylation Signature to Predict Prognosis in Stage II/III Colorectal Cancer.

With the increasing incidence of colorectal cancer (CRC) and continued difficulty in treating it using immunotherapy, there is an urgent need to identify an effective immune-related biomarker associated with the survival and prognosis of patients with this disease. DNA methylation plays an essential role in maintaining cellular function, and changes in methylation patterns may contribute to the development of autoimmunity, aging, and cancer. In this study, we aimed to identify a novel immune-related methylated signature to aid in predicting the prognosis of patients with CRC. We investigated DNA methylation patterns in patients with stage II/III CRC using datasets from The cancer genome atlas (TCGA). Overall, 182 patients were randomly divided into training (n = 127) and test groups (n = 55). In the training group, five immune-related methylated CG sites (cg11621464, cg13565656, cg18976437, cg20505223, and cg20528583) were identified, and CG site-based risk scores were calculated using univariate Cox proportional hazards regression in patients with stage II/III CRC. Multivariate Cox regression analysis indicated that methylated signature was independent of other clinical parameters. The Kaplan-Meier analysis results showed that CG site-based risk scores could significantly help distinguish between high- and low-risk patients in both the training (P = 0.000296) and test groups (P = 0.022). The area under the receiver operating characteristic curve in the training and test groups were estimated to be 0.771 and 0.724, respectively, for prognosis prediction. Finally, stratified analysis results suggested the remarkable prognostic value of CG site-based risk scores in CRC subtypes. We identified five methylated CG sites that could be used as an efficient overall survival (OS)-related biomarker for stage II/III CRC patients.

Case Report: Triple Primary Malignant Tumors of the Esophagus, Stomach, and Colon in a Patient With Genetic Analysis.

The incidence of multiple primary malignant tumors (MPMTs) has increased greatly with the progress of tumor diagnosis and therapy technology. However, triple primary cancer is still very rare, and its genetic change is not clear yet. This case report described a 70-year-old Chinese male patient with triple primary cancers of the esophagus, stomach and right-sided colon. Pathological examination confirmed that each malignant tumor developed independently. Next-generation sequencing (NGS) using a 599-gene panel revealed five TP53 mutations in three tumor tissues. These variations might contribute to development of the triple primary malignant tumors in the patient. The patient underwent laparoscopic feeding jejunostomy and postoperative radiotherapy for synchronous esophageal and gastric carcinomas. Then, he underwent laparoscopic-assisted resection of right-sided colonic cancer and lysis of abdominal adhesions. By the time of submitting this manuscript, the patient had been well and no sign of recurrence or metastasis had been observed. To the best of our knowledge, this case is the first one to clarify the genetic abnormalities of triple primary cancers of esophagus, stomach and colon in a Chinese patient. It may contribute to understanding the molecular pathogenesis of multiple primary digestive malignancies and providing valuable treatment strategies for the similar patients in the future.

Identification of a novel heterozygous germline RAD52 missense mutation in a patient with gallbladder carcinoma: A case report.

RATIONALE: Gallbladder carcinoma is a malignant biliary tract tumor which is characterized by poor prognosis. Recent advances in genomic medicine have identified a few novel germline mutations that contribute to the increased risk of gallbladder carcinoma. RAD52 is a crucial human deoxyribonucleic acid (DNA) repair gene involved in maintaining genomic stability and preventing tumor occurrence. PATIENT CONCERNS: A 57-year-old man was hospitalized for space-occupying lesions in the gallbladder. DIAGNOSIS: A diagnosis of gallbladder adenocarcinoma was made based on computed tomography, B-ultrasound, blood tests, and postoperative pathology. INTERVENTIONS: Next-generation sequencing using a 599-gene panel and Sanger sequencing were performed to validate the mutation in the proband and his family members, respectively. OUTCOMES: A novel potentially pathogenic heterozygous germline RAD52 missense mutation (c.276T > A: p.N92K) was identified in the patient. Sanger sequencing revealed that this variation was not observed in unaffected family members. LESSONS: We identified a novel heterozygous germline RAD52 missense mutation in a patient with gallbladder carcinoma. Our results added to the current body of knowledge. It also provides new insights into genetic counseling and targeted therapeutic strategies for patients with gallbladder carcinoma.

Comprehensive analysis of immune-related prognostic genes in the tumour microenvironment of hepatocellular carcinoma.

BACKGROUND: The mortality rate of hepatocellular carcinoma (HCC) remains high worldwide despite surgery and chemotherapy. Immunotherapy is a promising treatment for the rapidly expanding HCC spectrum. Therefore, it is necessary to further explore the immune-related characteristics of the tumour microenvironment (TME), which plays a vital role in tumour initiation and progression. METHODS: In this research, 866 immune-related differentially expressed genes (DEGs) were identified by integrating the DEGs of samples from The Cancer Genome Atlas (TCGA)-HCC dataset and the immune-related genes from databases (InnateDB; ImmPort). Afterwards, 144 candidate prognostic genes were defined through weighted gene co-expression network analysis (WGCNA). RESULTS: Seven immune-related prognostic DEGs were identified using the L1-penalized least absolute shrinkage and selection operator (LASSO) Cox proportional hazards (PH) model, and the ImmuneRiskScore model was constructed on this basis. The prognostic index of the ImmuneRiskScore model was then validated in the relevant dataset. Patients were divided into high- and low-risk groups according to the ImmuneRiskScore. Differences in the immune cell infiltration of patients with different ImmuneRiskScore values were clarified, and the correlation of immune cell infiltration with immunotherapy biomarkers was further explored. CONCLUSION: The ImmuneRiskScore of HCC could be a prognostic marker and can reflect the immune characteristics of the TME. Furthermore, it provides a potential biomarker for predicting the response to immunotherapy in HCC patients.

Emerging roles and underlying molecular mechanisms of DNAJB6 in cancer.

DNAJB6 also known as mammalian relative of DnaJ (MRJ) encodes a highly conserved member of the DnaJ/Hsp40 family of co-chaperone proteins that function with Hsp70 chaperones. DNAJB6 is widely expressed in all tissues, with higher expression levels detected in the brain. DNAJB6 is involved in diverse cellular functions ranging from murine placental development, reducing the formation and toxicity of mis-folded protein aggregates, to self-renewal of neural stem cells. Involvement of DNAJB6 is implicated in multiple pathologies such as Huntington's disease, Parkinson's diseases, limb-girdle muscular dystrophy, cardiomyocyte hypertrophy and cancer. This review summarizes the important involvement of the spliced isoforms of DNAJB6 in various pathologies with a specific focus on the emerging roles of human DNAJB6 in cancer and the underlying molecular mechanisms.

Loss of tumor suppressor Merlin results in aberrant activation of Wnt/ß-catenin signaling in cancer.

The expression of the tumor suppressor Merlin is compromised in nervous system malignancies due to genomic aberrations. We demonstrated for the first time, that in breast cancer, Merlin protein expression is lost due to proteasome-mediated elimination. Immunohistochemical analysis of tumor tissues from patients with metastatic breast cancer revealed characteristically reduced Merlin expression. Importantly, we identified a functional role for Merlin in impeding breast tumor xenograft growth and reducing invasive characteristics. We sought to determine a possible mechanism by which Merlin accomplishes this reduction in malignant activity. We observed that breast and pancreatic cancer cells with loss of Merlin show an aberrant increase in the activity of ß-catenin concomitant with nuclear localization of ß-catenin. We discovered that Merlin physically interacts with ß-catenin, alters the sub-cellular localization of ß-catenin, and significantly reduces the protein levels of ß-catenin by targeting it for degradation through the upregulation of Axin1. Consequently, restoration of Merlin inhibited ß-catenin-mediated transcriptional activity in breast and pancreatic cancer cells. We also present evidence that loss of Merlin sensitizes tumor cells to inhibition by compounds that target ß-catenin-mediated activity. Thus, this study provides compelling evidence that Merlin reduces the malignant activity of pancreatic and breast cancer, in part by suppressing the Wnt/ß-catenin pathway. Given the potent role of Wnt/ß-catenin signaling in breast and pancreatic cancer and the flurry of activity to test ß-catenin inhibitors in the clinic, our findings are opportune and provide evidence for Merlin in restraining aberrant activation of Wnt/ß-catenin signaling.

The Impact of Hedgehog Signaling Pathway on DNA Repair Mechanisms in Human Cancer.

Defined cellular mechanisms have evolved that recognize and repair DNA to protect the integrity of its structure and sequence when encountering assaults from endogenous and exogenous sources. There are five major DNA repair pathways: mismatch repair, nucleotide excision repair, direct repair, base excision repair and DNA double strand break repair (including non-homologous end joining and homologous recombination repair). Aberrant activation of the Hedgehog (Hh) signaling pathway is a feature of many cancer types. The Hh pathway has been documented to be indispensable for epithelial-mesenchymal transition, invasion and metastasis, cancer stemness, and chemoresistance. The functional transcription activators of the Hh pathway include the GLI proteins. Inhibition of the activity of GLI can interfere with almost all DNA repair types in human cancer, indicating that Hh/GLI functions may play an important role in enabling tumor cells to survive lethal types of DNA damage induced by chemotherapy and radiotherapy. Thus, Hh signaling presents an important therapeutic target to overcome DNA repair-enabled multi-drug resistance and consequently increase chemotherapeutic response in the treatment of cancer.

ALDH1A1 maintains ovarian cancer stem cell-like properties by altered regulation of cell cycle checkpoint and DNA repair network signaling.

OBJECTIVE: Aldehyde dehydrogenase (ALDH) expressing cells have been characterized as possessing stem cell-like properties. We evaluated ALDH+ ovarian cancer stem cell-like properties and their role in platinum resistance. METHODS: Isogenic ovarian cancer cell lines for platinum sensitivity (A2780) and platinum resistant (A2780/CP70) as well as ascites from ovarian cancer patients were analyzed for ALDH+ by flow cytometry to determine its association to platinum resistance, recurrence and survival. A stable shRNA knockdown model for ALDH1A1 was utilized to determine its effect on cancer stem cell-like properties, cell cycle checkpoints, and DNA repair mediators. RESULTS: ALDH status directly correlated to platinum resistance in primary ovarian cancer samples obtained from ascites. Patients with ALDHHIGH displayed significantly lower progression free survival than the patients with ALDHLOW cells (9 vs. 3 months, respectively p<0.01). ALDH1A1-knockdown significantly attenuated clonogenic potential, PARP-1 protein levels, and reversed inherent platinum resistance. ALDH1A1-knockdown resulted in dramatic decrease of KLF4 and p21 protein levels thereby leading to S and G2 phase accumulation of cells. Increases in S and G2 cells demonstrated increased expression of replication stress associated Fanconi Anemia DNA repair proteins (FANCD2, FANCJ) and replication checkpoint (pS317 Chk1) were affected. ALDH1A1-knockdown induced DNA damage, evidenced by robust induction of γ-H2AX and BAX mediated apoptosis, with significant increases in BRCA1 expression, suggesting ALDH1A1-dependent regulation of cell cycle checkpoints and DNA repair networks in ovarian cancer stem-like cells. CONCLUSION: This data suggests that ovarian cancer cells expressing ALDH1A1 may maintain platinum resistance by altered regulation of cell cycle checkpoint and DNA repair network signaling.

GLI1 upregulates C-JUN through a specific 130-kDa isoform.

The Hedgehog pathway is molecularly linked to increased resistance to cisplatin and increased repair of platinum-DNA damage, through C-JUN. GLI1, which has five known isoforms, is a positive transcriptional regulator in Hedgehog. Southwestern blot assay, EMSA and ChIP assays indicate that only one of five isoforms of GLI1 may be responsible for the Hedgehog link with C-JUN and thus, increased platinum-DNA adduct repair. Cancer tissues express this 130-kDa isoform at levels 6-fold higher than non-malignant tissues; and this isoform exists in abundance in six of seven ovarian cancer cell lines examined.

CD44+/CD24- ovarian cancer cells demonstrate cancer stem cell properties and correlate to survival.

Cancer cells with the surface marker profile CD44+/CD24- have previously been described to possess cancer stem cell-like properties. This manuscript evaluates those properties in ovarian cancer cell lines. The proportion of CD44+/CD24- cells corresponded to the clinical aggressiveness of each ovarian cancer cell line histologic subtype. CD44+/CD24- cells demonstrated enhanced progressive differentiation as well as showing a 60-fold increase in Matrigel invasion in both SKOV3 and OV90 cell lines (p < 0.001 each) compared to other phenotypes. CD44+/CD24- demonstrated significant resistance to all chemotherapy agents used in all cell lines, with a 71-93 % increase in resistance compared with baseline. Using a threshold of 25 % CD44+/CD24- ovarian cancer cells found in ascites, patients with >25 % CD44+/CD24- were significantly more likely to recur (83 vs. 14 %, p = 0.003) and had shorter median progression-free survival (6 vs. 18 months, p = 0.01). In conclusion, the CD44+/CD24- phenotype in ovarian cancer cells demonstrate cancer stem cell-like properties of enhanced differentiation, invasion, and resistance to chemotherapy. This CD44+/CD24- phenotype correlates to clinical endpoints with increased risk of recurrence and shorter progression-free survival in patients with ovarian cancer.

Targeted inhibition of telomerase activity combined with chemotherapy demonstrates synergy in eliminating ovarian cancer spheroid-forming cells.

OBJECTIVE: Telomerase activity (TA) is often used as a molecular marker for cancer aggressiveness. Our objectives were to determine the TA in ovarian cancer cell lines and the effectiveness of targeting telomerase for cancer therapy. METHODS: Ovarian cancer cell lines of various histologic subtypes were chosen to correspond to decreasing levels of clinical aggressiveness. Cells were grown in non-adherent growth conditions to form spheroid-forming cells (SFC). Telomerase activity was quantified using the TRAPeze RT Telomerase Detection Kit and confirmed with luciferase reporter plasmid containing promoter of human telomerase reverse transcriptase (hTERT). Cell proliferation survival assays were performed after treatment with a small molecule telomerase inhibitor BIBR1532 both with and without multiple chemotherapeutic agents. RESULTS: Compared to monolayer, TA from SFC correlated to the innate clinical aggressiveness of ovarian cancer cell lines ES2, SKOV3, and TOV112D. Treatment with BIBR1532 resulted in up to a 12-fold decrease in TA compared to controls. SFCs were significantly more resistant to BIBR1532 compared to monolayer cell lines; however, it showed reasonable efficacy at 100 uM. In combination assays, the addition of BIBR1532 to carboplatin yielded the most favorable results in regards to synergy in all three cell lines evaluated. CONCLUSIONS: Telomerase activity appears to correlate to the clinical aggressiveness seen in histologic subtypes of ovarian cancer. BIBR1532 demonstrated significant inhibition of TA as well as reasonable efficacy as a single agent. Inhibition of telomerase with BIBR1532 in combination with carboplatin demonstrated a more than additive effect in-vitro and could represent a novel targeted therapy for ovarian cancer.

Hedgehog signaling pathway regulates the growth of ovarian cancer spheroid forming cells.

The hedgehog (Hh) pathway has been shown to be activated in numerous malignancies as well as in cancer stem cells. We sought to determine the importance of the Hh pathway in regulating growth and development of ovarian cancer spheroid-forming cells (SFCs). Ovarian cancer cell lines (ES2, TOV112D, OV90, and SKOV3) as well as a normal ovarian epithelial cell line (IOSE80) were grown in non-adherent growth conditions to form SFCs. Western blot analysis was used to determine the expression of Hh pathway proteins SMOH, PTCH, GLI1. SFCs were treated with Hh agonists (SHH and IHH) as well as an Hh inhibitor (cyclopamine) to determine changes in spheroid growth and survival. All ovarian cancer cell lines readily formed spheroids in non-adherent growth conditions while IOSE80 failed to form SFCs. Compared to IOSE80, ovarian cancer cell lines demonstrated significant activation of the Hh pathway as defined by increased expression of intranuclear GLI1. Both Hh agonists demonstrated significant increases in spheroid volume of at least 42-fold for SHH-treated cells and 46-fold for IHH-treated cells. With regard to survival, SFCs were 30-50% more resistant to cyclopamine than their corresponding monolayer cells. Despite this resistance, inhibition of the Hh pathway with cyclopamine prevented further growth of SFCs with a 10-, 5-, and 4-fold restriction in growth for ES2, SKOV3, and TOV112D, respectively. The hedgehog pathway appears to be important in regulating growth of ovarian cancer spheroid-forming cells. The activation and inhibition of this pathway demonstrates significant correlation to enhanced growth and growth restriction, respectively.

High mobility group box 1 protein inhibits the proliferation of human mesenchymal stem cells and promotes their migration and differentiation along osteoblastic pathway.

Extracellular high mobility group box 1 (HMGB1) is a novel cytokine that takes part in the processes of inflammation, tissue damage and regeneration. Mesenchymal stem cells (MSCs) are adult stem cells characterized by their inherently suppressive activities on inflammative and allo-immune reactions. In the present study, we have addressed whether HMGB1 could affect the biological properties of human bone marrow MSCs. Transwell experiments showed that HMGB1 induced MSC migration and this effect could not be hampered by a blocking antibody against the receptor for advanced glycation end products (RAGE). MSCs exposed to HMGB1 were negative for CD31, CD45, CD80, and HLA-DR, and displayed equal levels of CD73, CD166, and HLA-ABC compared with their counterparts, but HMGB1 profoundly suppressed MSC proliferation in a dose-dependent manner as evaluated by carboxyfluorescein diacetate succinmidyl ester dye dilution assay. Furthermore, HMGB1 triggered the differentiation of MSCs into osteoblasts as identified by histochemical staining, traditional RT-PCR and real-time RT-PCR analysis on mRNA expression of lineage-specific molecular markers. The differentiation-inductive activity could neither be inhibited by RAGE neutralizing antibody. Moreover, HMGB1-treated MSCs displayed unchanged suppressive activity on in vitro lymphocyte cell proliferation elicited by ConA. Collectively, the data suggest that MSCs are a target of HMGB1.