Application of Immune Infiltration Signature and Machine Learning Model in the Differential Diagnosis and Prognosis of Bone-Related Malignancies.

Bone-related malignancies, such as osteosarcoma, Ewing's sarcoma, multiple myeloma, and cancer bone metastases have similar histological context, but they are distinct in origin and biological behavior. We hypothesize that a distinct immune infiltrative microenvironment exists in these four most common malignant bone-associated tumors and can be used for tumor diagnosis and patient prognosis. After sample cleaning, data integration, and batch effect removal, we used 22 publicly available datasets to draw out the tumor immune microenvironment using the ssGSEA algorithm. The diagnostic model was developed using the random forest. Further statistical analysis of the immune microenvironment and clinical data of patients with osteosarcoma and Ewing's sarcoma was carried out. The results suggested significant differences in the microenvironment of bone-related tumors, and the diagnostic accuracy of the model was higher than 97%. Also, high infiltration of multiple immune cells in Ewing's sarcoma was suggestive of poor patient prognosis. Meanwhile, increased infiltration of macrophages and B cells suggested a better prognosis for patients with osteosarcoma, and effector memory CD8 T cells and type 2 T helper cells correlated with patients' chemotherapy responsiveness and tumor metastasis. Our study revealed that the random forest diagnostic model based on immune infiltration can accurately perform the differential diagnosis of bone-related malignancies. The immune microenvironment of osteosarcoma and Ewing's sarcoma has an important impact on patient prognosis. Suppressing the highly inflammatory environment of Ewing's sarcoma and promoting macrophage and B cell infiltration may have good potential to be a novel adjuvant treatment option for osteosarcoma and Ewing's sarcoma.

A Delta-radiomics model for preoperative evaluation of Neoadjuvant chemotherapy response in high-grade osteosarcoma.

BACKGROUND: The difficulty of assessment of neoadjuvant chemotherapeutic response preoperatively may hinder personalized-medicine strategies that depend on the results from pathological examination. METHODS: A total of 191 patients with high-grade osteosarcoma (HOS) were enrolled retrospectively from November 2013 to November 2017 and received neoadjuvant chemotherapy (NCT). A cutoff time of November 2016 was used to divide the training set and validation set. All patients underwent diagnostic CTs before and after chemotherapy. By quantifying the tumor regions on the CT images before and after NCT, 540 delta-radiomic features were calculated. The interclass correlation coefficients for segmentations of inter/intra-observers and feature pair-wise correlation coefficients (Pearson) were used for robust feature selection. A delta-radiomics signature was constructed using the lasso algorithm based on the training set. Radiomics signatures built from single-phase CT were constructed for comparison purpose. A radiomics nomogram was then developed from the multivariate logistic regression model by combining independent clinical factors and the delta-radiomics signature. The prediction performance was assessed using area under the ROC curve (AUC), calibration curves and decision curve analysis (DCA). RESULTS: The delta-radiomics signature showed higher AUC than single-CT based radiomics signatures in both training and validation cohorts. The delta-radiomics signature, consisting of 8 selected features, showed significant differences between the pathologic good response (pGR) (necrosis fraction ≥90%) group and the non-pGR (necrosis fraction < 90%) group (P < 0.0001, in both training and validation sets). The delta-radiomics nomogram, which consisted of the delta-radiomics signature and new pulmonary metastasis during chemotherapy showed good calibration and great discrimination capacity with AUC 0.871 (95% CI, 0.804 to 0.923) in the training cohort, and 0.843 (95% CI, 0.718 to 0.927) in the validation cohort. The DCA confirmed the clinical utility of the radiomics model. CONCLUSION: The delta-radiomics nomogram incorporating the radiomics signature and clinical factors in this study could be used for individualized pathologic response evaluation after chemotherapy preoperatively and help tailor appropriate chemotherapy and further treatment plans.

Recurrence of Giant Cell Tumor of the Spine after Resection: A Report of 10 Cases.

OBJECTIVE: To review the clinical details and further treatments for recurrent spinal giant cell tumors (SGCT), and to analyze the risk factors of recurrence and shed new light on the treatment options and prognosis of recurrent SGCT. METHODS: A retrospective analysis of recurrent SGCT between April 2003 and January 2014 was performed. A total of 10 patients comprising 3 men and 7 women with a mean age of 28.9 years (range, 21-40 years) were included in the study. All complete clinical data, radiographs, CT, MRI, scans and pathological data were reviewed. The tumor locations and the regions involved were evaluated by CT and MRI. The blood supply of the tumors was evaluated by enhanced CT and MRI. The mean follow-up was 81.3 months (range, 35.7-172.1 months). RESULTS: All patients had Enneking stage 3 tumors; 9 (90%) of them had different extents of spinal canal involvement in the primary time period. All patients underwent intralesional resection during their first surgery. Only 1 patient received local adjuvant treatments; no patient underwent selective arterial embolization or used denosumab at that time. Only 1 patient underwent adjuvant radiotherapy postoperatively, and another patient used bisphosphonates. After recurrence, 1 patient was cured using denosumab, and 2 patients' disease was controlled through use of other medical treatments or adjuvant treatments. There were 3 repeated recurrences and 7 repeated surgical procedures were performed in 5 patients. There were 6 intralesional excisions and 1 decompression surgery. The mean relapse-free time after the first surgery was 32.3 months (range, 10.5-62.6 months). The overall mean relapse-free time was 40.2 months (range, 10.5-157 months). No distant metastasis was found in our series. At the final follow-up, 4 patients were disease free, 3 patients' disease was under control, 2 has progressive disease aggravation, while 1 patient died as a result of progression of disease 133.9 months after first surgery. CONCLUSION: Intralesional excision for recurrent spinal giant cell tumors is an effective option that may have satisfactory prognosis. However, the excision and the inactivation of the lesion should be carried out carefully and thoroughly without missing any corners. Early diagnosis of recurrence may be associated with better prognosis. Adjuvant treatments perioperatively and systemic medical treatments can decrease recurrence rates and can have therapeutic effects in the recurrent SGCT.

Zoledronic acid sensitizes rhabdomyosarcoma cells to cytolysis mediated by human γδ T cells.

Rhabdomyosarcoma (RMS) is the most common type of soft-tissue sarcoma in children. Immunotherapy has been proposed as a treatment for this deadly tumor. In the present study, the cytotoxicity of ex vivo expanded γδ T cells on RMS cell lines was evaluated and the molecular interactions involved were investigated. γδ T cells were expanded in vitro using peripheral blood mononuclear cells from 5 healthy donors and were stimulated with zoledronic acid (Zol) and interleukin 2. RMS cell lines RD and A-673 were used as target cells. The cytotoxicity of the γδ T cells against RMS was assessed in vitro and in vivo. γδ T cells were cytotoxic to RMS cells. Importantly, Zol markedly increased their cytotoxic potential. RMS cells treated with Zol-stimulated γδ T cells to produce interferon γ. γδ T cell-mediated cytotoxicity was primarily through the T cell receptor-dependent signaling pathway in blocking studies. Transfer of γδ T cells together with Zol into nude mice induced the regression of RD tumor xenotransplants. The results of the present study provide the rationale for the clinical evaluation of γδ T cells in RMS.

The role of CTLA-4 and PD-1 in anti-tumor immune response and their potential efficacy against osteosarcoma.

Immunotherapy is proved to be a promising therapeutic strategy against human malignancies. Evasion of immune surveillance is considered to be a major factor of malignant progression. Inhibitory receptors, especially CTLA-4 and PD-1, are found to play critical roles in the mediation of anti-tumor immune efficacy. Thus, antibodies targeting these immune checkpoints have emerged as the attractive treatment approaches to those patients with cancer. Osteosarcoma is highly malignant and current treatment remains a challenge, especially for those patients with metastasis. Despite some achievements, the effect of immunotherapy against osteosarcoma is still unsatisfactory. The present review attempts to show the role and mechanism of CTLA-4 and PD-1 in immune response and summarize the recent findings related to the effect of inhibitory receptor antibodies on the immune response against tumors, especially osteosarcoma, and the correlation between PD-1 or/and CTLA-4 expression and outcome of osteosarcoma patients. We further discuss the utilization of the combination therapy against osteosarcoma.

Trastuzumab enhanced the cytotoxicity of Vγ9Vδ2 T cells against zoledronate-sensitized osteosarcoma cells.

Preliminary studies of Vγ9Vδ2 T cells and zoledronate (ZOL) present promising reasons to exploit their immunotherapeutic potential for osteosarcoma treatment (OS). ZOL is a third-generation aminobisphosphonate (ABP) and is well established in the management of cancer-induced bone disease. However, ZOL is characterized by high tropism for bone matrix, and the efficacy of ZOL for sensitizing tumors remains to be optimized. Vγ9Vδ2 T cells are important effectors of antibody-dependent cell-mediated cytotoxicity (ADCC). In this study, we investigated whether Vγ9Vδ2 T cell-mediated killing of ZOL-pretreated OS cells could be increased by the anti-HER-2 monoclonal antibody trastuzumab (TTZ). The cytotoxic activity of Vγ9Vδ2 T cells against osteosarcoma was assessed by an MTS assay in the presence or absence of TTZ. A CD107a assay was used to measure degranulation in cytotoxic Vγ9Vδ2 T cells. Blocking studies were used to determine the effect of relative ligands on Vγ9Vδ2 T cell recognition. TTZ induced an ADCC response in the OS cell line, U2OS; however, it had no effect on another OS cell line HOS with low levels of surface HER2 expression. Although the OS cells pretreated with ZOL for clinically relevant time periods (2hours) stimulated a suboptimal immune response of Vγ9Vδ2 T cells, TTZ could further enhance the cytotoxicity of Vγ9Vδ2 T cells. These results demonstrate that combining TTZ and ZOL significantly increases the cytotoxic potential of Vγ9Vδ2 T cells. This study raises the possibility of utilizing ZOL and TTZ in Vγ9Vδ2 T cell-based immunotherapy for OS.