Defining optimal cutoff value of MGMT promoter methylation by ROC analysis for clinical setting in glioblastoma patients.

Resistance to temozolomide (TMZ) chemotherapy poses a significant challenge in the treatment of glioblastoma (GBM). Hypermethylation in O6-methylguanine-DNA methyltransferase (MGMT) promoter is thought to play a critical role in this resistance. Pyrosequencing (PSQ) has been shown to be accurate and robust for MGMT promoter methylation testing. The unresolved issue is the determination of a cut-off value for dichotomization of quantitative MGMT PSQ results into "MGMT methylated" and "MGMT unmethylated" patient subgroups as a basis for further treatment decisions. In this study, receiver operating characteristic (ROC) curve analysis was used to identify an optimal cutoff of MGMT promoter methylation by testing mean percentage of methylation of 4 CpG islands (76-79) within MGMT exon 1. The area under the ROC (AUC) as well as the best cutoff to classify the methylation were calculated. Positive likelihood ratio (LR+) was chosen as a diagnostic parameter for defining an optimal cut-off. Meanwhile, we also analyzed whether mean percentage of methylation at the investigated CpG islands could be regarded as a marker for evaluating prognostication. ROC analysis showed that the optimal threshold was 12.5% (sensitivity: 60.87%; specificity: 76%) in response to the largest LR+ 2.54. 12.5% was established to distinguish MGMT promoter methylation, which was confirmed using validation set. According to the cutoff value, the MGMT promoter methylation was found in 58.3% of GBM. Mean methylation level of the investigated CpG sites strong correlated with overall survival (OS), which means GBM patients with a high level of methylation survived longer than those with low level of methylation(log-rank test, P = 0.017). In conclusion, ROC curve analysis enables the best cutoff for discriminating MGMT promoter methylation status. LR+ can be used as a key factor that evaluates cutoff. The promoter methylation level of MGMT by PSQ in GBM patients had prognostic value.

An Explanation of the Underlying Mechanisms for the In Vitro and In Vivo Antiurolithic Activity of Glechoma longituba.

Purpose. To use in vitro and in vivo models to evaluate Glechoma longituba extract to provide scientific evidence for this extract's antiurolithic activity. Materials and Methods. Potassium citrate was used as a positive control group. Oxidative stress (OS) markers and the expression of osteopontin (OPN) and kidney injury molecule-1 (KIM-1) were measured to assess the protective effects of Glechoma longituba. Multiple urolithiasis-related biochemical parameters were evaluated in urine and serum. Kidneys were harvested for histological examination and the assessment of crystal deposits. Results. In vitro and in vivo experiments demonstrated that treatment with Glechoma longituba extract significantly decreased calcium oxalate- (CaOx-) induced OPN expression, KIM-1 expression, and OS compared with the positive control group (P < 0.05). Additionally, in vivo rats that received Glechoma longituba extract exhibited significantly decreased CaOx deposits and pathological alterations (P < 0.05) compared with urolithic rats. Significantly lower levels of oxalate, creatinine, and urea and increased citrate levels were observed among rats that received Glechoma longituba (P < 0.05) compared with urolithic rats. Conclusion. Glechoma longituba has antiurolithic effects due to its possible combined effects of increasing antioxidant levels, decreasing urinary stone-forming constituents and urolithiasis-related protein expression, and elevating urinary citrate levels.

[Individualized therapy and outcomes of microsurgery, radiotherapy, and chemotherapy for astrocytoma].

BACKGROUND & OBJECTIVE: Astrocytomas, constitute about 75% of neuroepithelial tumors, is one of the most common primary tumors in central nervous system with fairly high incidence and poor prognosis. Individualized multimodality is the hope for improving prognosis of patients with astrocytoma. This study was designed to investigate the efficiency of individualized treatment of microsurgery, radiotherapy, and chemotherapy for 62 patients with astrocytoma. METHODS: Sixty-two patients with astrocytoma in study group were treated with individualized multimodality of microsurgery, postoperative radiotherapy, and/or postoperative chemotherapy according to in vitro sensitivity assay. After microsurgery, 59 patients accepted radiotherapy, 46 patients received chemotherapy. Fifty patients with astrocytoma in control group were treated with conventional treatment of surgery, chemotherapy, and radiotherapy. After surgery, 31 patients received radiotherapy following by BCNU chemotherapy, while 19 patients accepted BCNU chemotherapy following radiotherapy. Pathologic diagnosis of patients in study group were 19 cases of grade, 32 cases of grade III, and 11 cases of grade IV; in control group were 13 cases of grade II, 28 cases of grade III, and 9 cases of grade IV. Mean follow-up time were 25.8 months, and the outcome was evaluated by MRI, KPS, and survival rate. RESULTS: Tumor total resection rate in study group was 67.7%, while that in control group was 58.0%. There was no significant difference of KPS and survival rate in patients with low-grade astrocytoma between 2 groups, while the outcome of patients with malignant astrocytoma was significantly improved by individualized treatment. In study group, 2-year expectant survival rate of patients with astrocytoma of grade III, and grade IV were 93.7%, and 36.3%, while in control group were 67.5%, and 22.2% (P< 0.05). In glioblastoma patients, median survival time of study group was 18.68 months, while that of control group was 12.83 months (P< 0.01). CONCLUSION: Individualized microsurgery may improve the total resection of astrocytoma, and benefit to postoperative treatment.Individualized radiotherapy/chemotherapy may prevent patients from some complications. Individualized management may improve prognosis of patients with astrocytoma, particularly malignant astrocytoma.

[Microsurgical technique of brain glioma---a report of 183 cases].

BACKGROUND & OBJECTIVE: Prognosis of glioma is still poor, its main treatment is surgery. The extent of tumor resection relates with prognosis. This study was to evaluate the extent of resection, post-operative Karnofsky performance scale (KPS), and survival rate of the glioma patients received microsurgery. METHODS: Records of 183 glioma patients received microneurosurgery were retrospectively analyzed, the extent of resection, post-operative KPS, and survival rate of patients were evaluated. Different microsurgical techniques were applied according to the location of gliomas. En bloc resection was performed for gliomas in non-functional areas by dissecting the tumors along edema area with high-power bipolar electrocoagulation. The tumors in functional areas were separated along cortex sulcus, the central part of tumor was removed firstly, and residual part was resected with low-power electrocoagulation. Gliomas close to important vessels were sucked, and electrocoagulation seldom performed. RESULTS: Among 183 cases of glioma, 85 in non-functional area, 47 in functional area, and 51 close to important vessels. Total and sub-total resection was performed in 163 patients (89.1%). The average post-operative KPS was 74. The KPS was decreased in 23 patients, increased in 44 patients, and stable in 116 patients. Patients were followed up for 12-216 months with an average of 47.8 months. The follow-up rate was 100%. Among 113 patients with long-term follow-up (>/=5 years), 5-year survival rates of low-grade, and high-grade astrocytoma patients were 75.4% (52/69), and 18.2% (8/44). CONCLUSION: Using different microsurgical patterns according to location of glioma, maximal resection of tumor may achieve with protection of neurological function.