Efficacy of concurrent chemoradiotherapy alone for loco-regionally advanced nasopharyngeal carcinoma: long-term follow-up analysis.

BACKGROUND: To analysis the clinical outcomes of concurrent chemoradiotherapy (CCRT) alone based on 10-year results for loco-regionally advanced nasopharyngeal carcinoma (LANPC), so as to provide evidence for individualized treatment strategy and designing appropriate clinical trial for different risk LANPC patients. METHODS: Consecutive patients with stage III-IVa (AJCC/UICC 8th) were enrolled in this study. All patients received radical intensity-modulated radiotherapy (IMRT) and concurrent cisplatin chemotherapy (CDDP). The hazard ratios (HRs) of death risk in patients with T3N0 was used as baseline, relative HRs were calculated by a Cox proportional hazard model to classify different death risk patients. Survival curves for the time-to-event endpoints were analyzed by the Kaplan-Meier method and compared using the log-rank test. All statistical tests were conducted at a two-sided level of significance of 0.05. RESULTS: A total of 456 eligible patients were included. With 12-year median follow-up, 10-year overall survival (OS) was 76%. 10-year loco-regionally failure-free survival (LR-FFS), distant failure-free survival (D-FFS) and failure-free survival (FFS) were 72%, 73% and 70%, respectively. Based on the relative hazard ratios (HRs) of death risk, LANPC patients were classified into 3 subgroups, low-risk group (T1-2N2 and T3N0-1) contained 244 patients with HR < 2; medium-risk group (T3N2 and T4N0-1) contained 140 patients with HR of 2 - 5; high-risk group (T4N2 and T1-4N3) contained 72 patients with HR > 5. The 10-year OS for patients in low-, medium-, and high-risk group were 86%, 71% and 52%, respectively. Significantly differences of OS rates were found between each of the two groups (low-risk group vs. medium-risk group, P < 0.001; low-risk group vs. high-risk group, P < 0.001; and medium-risk group vs. high-risk group, P = 0.002, respectively). Grade 3-4 late toxicities included deafness/otitis (9%), xerostomia (4%), temporal lobe injury (5%), cranial neuropathy (4%), peripheral neuropathy (2%), soft tissue damage (2%) and trismus (1%). CONCLUSIONS: Our classification criteria demonstrated that significant heterogeneity in death risk among TN substages for LANPC patients. IMRT plus CDDP alone maybe suitable for low-risk LANPC (T1-2N2 or T3N0-1), but not for medium- and high-risk patients. These prognostic groupings provide a practicable anatomic foundation to guide individualized treatment and select optimal targeting in the future clinical trials.

Increased MCL-1 synthesis promotes irradiation-induced nasopharyngeal carcinoma radioresistance via regulation of the ROS/AKT loop.

Worldwide, nasopharyngeal carcinoma (NPC) is a rare head and neck cancer; however, it is a common malignancy in southern China. Radiotherapy is the most important treatment strategy for NPC. However, although radiotherapy is a strong tool to kill cancer cells, paradoxically it also promotes aggressive phenotypes. Therefore, we mimicked the treatment process in NPC cells in vitro. Upon exposure to radiation, a subpopulation of NPC cells gradually developed resistance to radiation and displayed cancer stem-cell characteristics. Radiation-induced stemness largely depends on the accumulation of the antiapoptotic myeloid cell leukemia 1 (MCL-1) protein. Upregulated MCL-1 levels were caused by increased stability and more importantly, enhanced protein synthesis. We showed that repeated ionizing radiation resulted in persistently enhanced reactive oxygen species (ROS) production at a higher basal level, further promoting protein kinase B (AKT) signaling activation. Intracellular ROS and AKT activation form a positive feedback loop in the process of MCL-1 protein synthesis, which in turn induces stemness and radioresistance. AKT/MCL-1 axis inhibition attenuated radiation-induced resistance, providing a potential target to reverse radiation therapy-induced radioresistance.

Docetaxel and cisplatin induction chemotherapy with or without fluorouracil in locoregionally advanced nasopharyngeal carcinoma: A retrospective propensity score matching analysis.

PURPOSE: To investigate whether the addition of fluorouracil to docetaxel and cisplatin induction chemotherapy (IC) can truly improve the prognosis of patients with locoregionally advanced nasopharyngeal carcinoma (NPC). METHODS: A total of 801 patients newly diagnosed with non-metastatic locoregionally advanced NPC were included as the subjects. In this study, propensity score matching (PSM) was used for analysis of overall survival (OS), distant metastasis-free survival (DMFS), progression-free survival (PFS) and locoregional relapse-free survival (LRRFS), and the chi-squared test or Fisher's exact test was used to investigate toxic reactions. RESULTS: Patients received treatment with docetaxel and cisplatin (TP) or docetaxel, cisplatin and fluorouracil (TPF). With a median follow-up time of 60 months (range: 5-124 months), the TPF group had better 5-year OS (84.7% vs 79.0%; P = 0.037), PFS (84.6% vs 76.8%; P = 0.008) and DMFS (89.5% vs 82.3%; P = 0.004) than the TP group. After PSM, 258 patients were matched in each cohort. The Kaplan-Meier analysis showed that the 5-year OS, PFS and DMFS were 85.5%, 84.2% and 89.2%, respectively, in the TPF group, higher than the 80.8%, 75.0% and 81.4%, respectively, in the TP group (P = 0.048, 0.009 and 0.006, respectively). Moreover, the multivariate analysis revealed that different IC regimens were independent prognostic factors for PFS and DMFS (P = 0.014 and 0.010, respectively). CONCLUSION: This study found that compared with the TP regimen, TPF induction chemotherapy is associated with improved survival in patients with locoregionally advanced NPC. TPF can produce more mucosal and nausea/vomiting adverse reactions than TP.

Adjuvant chemotherapy following combined induction chemotherapy and concurrent chemoradiotherapy improves survival in N2-3-positive nasopharyngeal carcinoma patients.

OBJECTIVE: This study aimed to explore the clinical value of adjuvant chemotherapy (ACT) following concurrent chemo-radiotherapy (CCRT) and induction chemotherapy (ICT) in loco-regionally advanced nasopharyngeal carcinoma (LANC). METHODS: We included 839 newly diagnosed LANC patients in this study. ICT plus CCRT (ICT + CCRT group) was administered to 443 patients, and 396 patients received ACT after ICT plus CCRT (ICT + CCRT + ACT group). Univariate and multivariate Cox regression analyses were carried out. Furthermore, propensity score matching (PSM) was applied to balance the study and control groups. RESULTS: A total of 373 pairs of LANC patients were obtained after PSM analysis. We found that ACT following ICT + CCRT has no significant effect on improving the survival of LANC patients. By further exploring the ICT + CCRT + ACT treatment protocol, we excluded N0-1-positive patients and re-performed PSM in the ICT + CCRT and ICT + CCRT + ACT groups. Each group consisted of 237 patients. Kaplan-Meier analysis revealed that there were differences between the ICT + CCRT and ICT + CCRT + ACT groups in terms of the 5-year overall survival (OS) (78.9% vs. 85.0%, P = 0.034), disease-free survival (DFS) (73.4% vs. 81.7%, P = 0.029), and distant metastasis-free survival (DMFS) (84.9% vs. 76.0%, P = 0.019). In addition, the ICT + CCRT + ACT group had a higher incidence of grade 3/4 acute leukocytopenia/neutropenia. CONCLUSION: Compared with ICT + CCRT, ACT following ICT plus CCRT can reduce distant metastasis of N2-3-positive LANC and improve the OS and DFS. The results demonstrated the feasibility and clinical utility of ACT following ICT plus CCRT.

The Optimal Second-Line Systemic Treatment Model for Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma: A Bayesian Network Meta-Analysis.

Background: The optimal second-line systemic treatment model for recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC) remains controversial. A Bayesian network meta-analysis (NMA) was performed to address this issue with regard to efficacy and toxicity. Methods: By searching MEDLINE (via PubMed), Embase, the Cochrane Central Register of Controlled Trials and Web of Science, we extracted eligible studies. Efficacy, represented as overall survival (OS) and progression-free survival (PFS), and overall toxicity, represented as ≥ grade 3 severe acute events (sAE), were assessed to compare the following 7 treatment models through an NMA: standard-of-care therapy (SoC), single targeted therapy different from SoC (ST), double targeted therapy (DT), targeted therapy combined with chemotherapy (T+C), single immune checkpoint inhibitor therapy (SI), double immune checkpoint inhibitor therapy (DI) and single chemotherapy different from SoC (SC). Rank probabilities according to the values of the surface under the cumulative ranking curve (SUCRA) were separately determined for efficacy and toxicity. Results: In total, 5285 patients from 24 eligible studies were ultimately screened, with 5184, 4532 and 4026 involved in the NMA of OS, PFS and sAE, respectively. All qualifying studies were absent from first-line immune checkpoint inhibitor therapy. In terms of OS, SI was superior to the other treatments, followed by DI, ST, T+C, SoC, DT and SC. Other than SI and SC, all treatments tended to be consistent, with hazard ratios (HRs) close to 1 between groups. For PFS, ST ranked first, while DT ranked last. For the toxicity profiles, compared with the other models, SI resulted in the lowest incidences of sAE, with statistical significance over SoC (odds ratio [OR] 0.31, 95% credible interval [CrI] 0.11 to 0.90), ST (OR 0.23, 95% CrI 0.06 to 0.86) and DT (OR 0.11, 95% CrI 0.02 to 0.53), while DT was the worst. When the SUCRA values of OS and sAE were combined, a cluster plot illustrated the superiority of SI, which demonstrated the best OS and tolerability toward sAE. Conclusion: For R/M HNSCC patients without immune checkpoint inhibitors in the first-line setting, SI may serve as the optimal second-line systemic treatment model, demonstrating the best OS and least sAE.

Clinical value of docetaxel plus cisplatin (TP) induction chemotherapy followed by TP concurrent chemoradiotherapy in locoregionally advanced nasopharyngeal carcinoma.

Objective: To investigate the clinical value of induction chemotherapy (IC) with docetaxel plus cisplatin (TP) followed by concurrent chemoradiotherapy (CCRT) with TP in locoregionally advanced nasopharyngeal carcinoma (NPC). Methods: A total of 544 patients with locoregionally advanced NPC that was newly diagnosed from January 2009 to December 2015 were included in this study. Among these patients, 251 were treated with TP induction chemotherapy followed by CCRT with cisplatin (DDP) alone (TP + DDP group), 167 were treated with TP followed by CCRT with TP (TP + TP group), and 126 were treated with docetaxel, DDP and fluorouracil (TPF) followed by CCRT with DDP alone (TPF + DDP group). Overall survival (OS), distant metastasis-free survival (DMFS), progression-free survival (PFS) and locoregional relapse-free survival (LRRFS) were analyzed using the Kaplan-Meier method and a Cox proportional hazards model. Results: Survival analysis showed that the 5-year OS, PFS and DMFS rates in the TP + DDP group were significantly lower than those in the TP + TP group after propensity score matching (PSM). Multivariate analysis revealed that CCRT with TP was an independent prognostic factor for OS, PFS and DMFS. During CCRT, the incidence rates of grade 3/4 nausea/vomiting, oral mucositis, leukocytopenia and neutropenia were significantly increased in the TP + TP group compared with the TP + DDP group (all P < 0.05). To further explore the value of TP + TP, we performed PSM again with the TPF + DDP group. After PSM, there were 100 patients in each group. Survival analysis showed no significant differences in the 5-year OS, PFS, DMFS and LRRFS rates between the two groups. During IC and CCRT, the rate of grade 3/4 nausea/vomiting in the TPF + DDP group was higher than that in the TP+TP group (9.0% vs. 2.0%, P = 0.030; 18.0% vs. 8.0%, P = 0.036, respectively). No significant difference in the incidence of grade 3/4 hematologic toxicity was found between the two groups (all P > 0.05). Conclusion: TP + TP can reduce the distant metastasis of locoregionally advanced NPC and improve OS compared with TP + DDP; TP + TP has the same effect as TPF + DDP and is clinically feasible.

Clinical value of nedaplatin-based chemotherapy combined with radiotherapy for locoregional advanced nasopharyngeal carcinoma: a retrospective, propensity score-matched analysis.

Aims: This study aimed to investigate the clinical value of induction chemotherapy (IC) with docetaxel, 5-fluorouracil plus nedaplatin followed by concurrent chemoradiotherapy (CCRT) with nedaplatin for locoregional advanced nasopharyngeal carcinoma (NPC). Materials and Methods: In total, 269 patients diagnosed with locoregional advanced NPC between June 2012 and June 2017 were retrospectively included and divided into two groups: IC (docetaxel plus nedaplatin and 5-fluorouracil) followed by nedaplatin-based CCRT (TNF + N group, n = 146) and IC (docetaxel plus cisplatin and 5-fluorouracil) followed by cisplatin-based CCRT (TPF + P group, n = 123). The Kaplan-Meier method and Cox proportional hazards model were applied to analyse survival and prognosis. After propensity score-matched (PSM), 113 patients remained in each group. Toxicities were compared between the two groups using the Chi-square test or Fisher's exact test. Results: The overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) rates of the TNF + N and TPF + P groups were 90.7% vs. 92.3% (P = 0.315), 78.9% vs. 79.4% (P = 0.715), 82.4% vs. 85.1% (P = 0.441) and 96.1% vs. 93.3% (P = 0.414), respectively, with no significant difference in 3-year survival outcome between the two groups, and this outcome was confirmed after using PSM analyses. In the PSM cohort, a significant higher frequency of grade 3/4 vomiting was observed in the TPF + P group compared to the TNF + N group (22.1% vs. 0%, P = 0.000). However, 15.9% of patients in the TNF + N group had grade 3/4 thrombocytopenia in comparison with 6.2% in the TPF + P group (P = 0.020). Conclusions: The TNF regimen followed by CCRT with nedaplatin is an alternative treatment strategy to the standard TPF regimen followed by CCRT with cisplatin for patients with locoregional advanced NPC.

RASSF1A inhibits PDGFB-driven malignant phenotypes of nasopharyngeal carcinoma cells in a YAP1-dependent manner.

Nasopharyngeal carcinoma (NPC) is a highly aggressive tumor characterized by distant metastasis. Deletion or down-regulation of the tumor suppressor protein ras-association domain family protein1 isoform A (RASSF1A) has been confirmed to be a key event in NPC progression; however, little is known about the effects or underlying mechanism of RASSF1A on the malignant phenotype. In the present study, we observed that RASSF1A expression inhibited the malignant phenotypes of NPC cells. Stable silencing of RASSF1A in NPC cell lines induced self-renewal properties and tumorigenicity in vivo/in vitro and the acquisition of an invasive phenotype in vitro. Mechanistically, RASSF1A inactivated Yes-associated Protein 1 (YAP1), a transcriptional coactivator, through actin remodeling, which further contributed to Platelet Derived Growth Factor Subunit B (PDGFB) transcription inhibition. Treatment with ectopic PDGFB partially increased the malignancy of NPC cells with transient knockdown of YAP1. Collectively, these findings suggest that RASSF1A inhibits malignant phenotypes by repressing PDGFB expression in a YAP1-dependent manner. PDGFB may serve as a potential interest of therapeutic regulators in patients with metastatic NPC.

Melatonin reverses nasopharyngeal carcinoma cisplatin chemoresistance by inhibiting the Wnt/ß-catenin signaling pathway.

Cisplatin (DDP)-based concurrent chemo-radiotherapy is a standard approach to treat locoregionally advanced nasopharyngeal carcinoma (NPC). However, many patients eventually develop recurrence and/or distant metastasis due to chemoresistance. In this study, we aimed to elucidate the effects of melatonin on DDP chemoresistance in NPC cell lines in vitro and vivo, and we explored potential chemoresistance mechanisms. We found that DDP chemoresistance in NPC cells is mediated through the Wnt/ß-catenin signaling pathway. Melatonin not only reversed DDP chemoresistance, but also enhanced DDP antitumor activity by suppressing the nuclear translocation of ß-catenin, and reducing expression of Wnt/ß-catenin response genes in NPC cells. In vivo, combined treatment with DDP and melatonin reduced tumor burden to a greater extent than single drug-treatments in an orthotopic xenograft mouse model. Our findings provide novel evidence that melatonin inhibits the Wnt/ß-catenin pathway in NPC, and suggest that melatonin could be applied in combination with DDP to treat NPC.

NFAT1 Hypermethylation Promotes Epithelial-Mesenchymal Transition and Metastasis in Nasopharyngeal Carcinoma by Activating ITGA6 Transcription.

DNA methylation is an important epigenetic change in carcinogenesis. However, the function and mechanism of DNA methylation dysregulation in nasopharyngeal carcinoma (NPC) is still largely unclear. Our previous genome-wide microarray data showed that NFAT1 is one of the most hypermethylated transcription factor genes in NPC tissues. Here, we found that NFAT1 hypermethylation contributes to its down-regulation in NPC. NFAT1 overexpression inhibited cell migration, invasion, and epithelial-mesenchymal transition in vitro and tumor metastasis in vivo. We further established that the tumor suppressor effect of NFAT1 is mediated by its inactivation of ITGA6 transcription. Our findings suggest the significance of activating NFAT1/ITGA6 signaling in aggressive NPC, defining a novel critical signaling mechanism that drives NPC invasion and metastasis and providing a novel target for future personalized therapy.

RASSF6-mediated inhibition of Mcl-1 through JNK activation improves the anti-tumor effects of sorafenib in renal cell carcinoma.

Ras association domain family member 6 (RASSF6) has been shown to act as a tumor suppressor and predictor of poor prognosis in renal cell carcinoma (RCC). However, little is known about the effects of RASSF6 on sorafenib resistance or the underlying mechanism. Here, we show that RASSF6 expression positively correlates with sorafenib sensitivity in RCC cells and human samples. Stable ectopic overexpression of RASSF6 in RCC cell lines reduces resistance to sorafenib in vitro and in vivo. At a molecular level, RASSF6 activates the JNK signaling pathway, which further contributes to Mcl-1 inhibition. Suppression of the JNK pathway can partially restore Mcl-1 expression and sorafenib resistance. Together, these findings suggest that RASSF6 inhibits sorafenib resistance by repressing Mcl-1 through the JNK-dependent pathway. RASSF6 may serve as a novel regulator for sorafenib therapy in RCC.

Aldose reductase interacts with AKT1 to augment hepatic AKT/mTOR signaling and promote hepatocarcinogenesis.

Marked up-regulation of aldose reductase (AR) is reportedly associated with the development of hepatocellular carcinoma (HCC). We investigated how aberrantly overexpressed AR might promote oncogenic transformation in liver cells and tissues. We found that overexpressed AR interacted with the kinase domain of AKT1 to increase AKT/mTOR signaling. In both cultured liver cancer cells and liver tissues in DEN-induced transgenic HCC model mice, we observed that AR overexpression-induced AKT/mTOR signaling tended to enhance lactate formation and hepatic inflammation to enhance hepatocarcinogenesis. Conversely, AR knockdown suppressed lactate formation and inflammation. Using cultured liver cancer cells, we also demonstrated that AKT1 was essential for AR-induced dysregulation of AKT/mTOR signaling, metabolic reprogramming, antioxidant defense, and inflammatory responses. These findings suggest that aberrantly overexpressed/over-activated hepatic AR promotes HCC development at least in part by interacting with oncogenic AKT1 to augment AKT/mTOR signaling. Inhibition of AR and/or AKT1 might serve as an effective strategy for the prevention and therapy of liver cancer.

Do glioma patients derive any therapeutic benefit from taking a higher cumulative dose of temozolomide regimens?: a meta-analysis.

Temozolomide (TMZ) is an oral alkylating agent with established effects on the central nervous system of glioblastoma (GBM) patients. Clinical trials have demonstrated a significant impact on overall survival (OS) with TMZ. Ever since, several TMZ regimens have been designed to improve treatment efficacy by increasing the cumulative dose per cycle. We report a meta-analysis to systematically evaluate different treatment schedules of TMZ in GBM patients.All searches that were conducted in the Cochrane library, Science Direct, and PubMed Databases, and 3 randomized controlled trials (1141 patients) were included. OS and progression-free survival (PFS) were the primary outcomes to be pooled.Unexpectedly, this analysis did not reveal any OS or PFS advantage for the high cumulative dose (HCD) regimen compared with the normal cumulative dose regimen (1141 total patients; hazard ratio [HR] 1.07, 95% CI 0.94-1.22, P = 0.31). Then after analyzing the characteristics of the results from each trial, we found that the regimen with a higher peak concentration during a short-term period (daily doses ≥150 mg/m/d within ≤7 days/cycle) always had a more superior clinical benefit. So we generated a new pooled HR of 1.10 with a 95% CI of 0.96-1.25 (P = 0.17), which prefers the high peak concentration schedule even without a significant difference. The adverse outcome also indicates a significant increased risk of leukopenia (risk ratio 1.59, 95% CI 1.03-2.46, P = 0.04) among the HCD group.Our study suggests that increasing the cumulative dose per cycle is not an ideal way to improve the efficacy of TMZ, and it will lead to increased risk for leukopenia. Future trials should be designed to examine schedules of higher peak concentration rather than the cumulative dose per cycle.

Localization of prestin and expression in the early period after radiation in mice.

This study aimed to examine expression and microstructural distribution of prestin in outer hair cells, and the effect of dose and time of radiation on prestin expression in the BALB/c mouse. We also investigated the molecular biological characteristics of prestin and possible mechanisms of sensorineural hearing loss caused by radiation. Seventy 4-week-old mice were randomly divided into four groups, including one control group and three experimental groups. Each experimental group was randomly divided into two groups, which were killed to collect specimens of the cochlea on the 3rd and 7th days after exposure to different doses of 8, 12, and 16 Gy radiation. These cochleas were embedded in paraffin, and then cut into sections. The sections were immunostained with anti-prestin antibodies. The distribution of prestin was observed under optical microscopy and the density of prestin-positive expression was quantitatively calculated by Image-Pro Plus. Prestin had high expression in the lateral membrane and low expression in the cytoplasm of outer hair cells above the nucleus. The density of prestin protein expression of the basal turn was not significantly different after exposure to the different doses of radiation compared with the control group, but up-regulation occurred after radiation in the apex turn. We conclude that prestin protein is mainly expressed in the lateral membrane above the nucleus. Prestin protein may be responsible for the mechanism of injury to the inner ear caused by radiation.

Stereotactic neurosurgical technique and electrophysiological study in ablating the ventromedial shell of the nucleus accumbens.

OBJECTIVE: To describe in as much detail as possible the method for ablating the ventromedial shell of the nucleus accumbens (NAc) and investigate the efficacy and safety of the ablation treatment. METHODS: Sixty-five patients with drug addictions received operations within the time frame from 2004 to 2009. The ablation targets were located in the bilateral medial posterior inferior shell of the NAc. Intraoperative electrophysiological monitoring was performed. RESULTS: Tissue impedance in the shell of the NAc varied from 185 to 355 Ω. When stimulated with a low frequency (2 Hz) and a voltage above 3 V, 57 out of 65 (87.7%) patients experienced slight throbbing sensations. During the lesion procedure, fever was detected on the head and face of 59 patients (90.8%), the heart rate decreased in 19 cases (29.2%), and restlessness, irritability and hyperalgia were noted for all patients. Among the 65 patients, 52 (80%) no longer experienced a psychological craving for the drug. CONCLUSIONS: The shell of the NAc may be a promising surgical target for psychosurgery. Electrophysiological recordings revealed that the shell is indeed an appropriate structure.

Radiation-induced Cochlea hair cell death: mechanisms and protection.

Cochlea hair cell death is regarded to be responsible for the radiation-induced sensorineural hearing loss (SNHL), which is one of the principal complications of radiotherapy (RT) for head and neck cancers. In this mini- review, we focus on the current progresses trying to unravel mechanisms of radiation-induced hair cell death and find out possible protection. P53, reactive oxygen species (ROS) and c-Jun N-terminal kinase (JNK) pathways have been proposed as pivotal in the processes leading to radiation hair cell death. Potential protectants, such as amifostine, N-acetylcysteine (NAC) and epicatechin (EC) , are claimed to be effective at reducing radiation- inducedhair cell death. The RT dosage, selection and application of concurrent chemotherapy should be pre- examined in order to minimize the damage to cochlea hair cells.

Meta-analysis of outcomes compared between robotic and laparoscopic gastrectomy for gastric cancer.

This meta-analysis was performed to evaluate and compare the outcomes of robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) for treating gastric cancer. A systematic literature search was carried out using the PubMed database, Web of Knowledge, and the Cochrane Library database to obtain comparative studies assessing the safety and efficiency between RG and LG in May, 2013. Data of interest were analyzed by using of Review Manager version 5.2 software (Cochrane Collaboration). A fixed effects model or random effects model was applied according to heterogeneity. Seven papers reporting results that compared robotic gastrectomy with laparoscopic gastrectomy for gastric cancer were selected for this meta-analysis. Our meta- analysis included 2,235 patients with gastric cancer, of which 1,473 had undergone laparoscopic gastrectomy, and 762 had received robotic gastrectomy. Compared with laparoscopic gastrectomy, robotic gastrectomy was associated with longer operative time but less blood loss. There were no significant difference in terms of hospital stay, total postoperative complication rate, proximal margin, distal margin, numbers of harvested lymph nodes and mortality rate between robotic gastrectomy and laparoscopic gastrectomy. Our meta-analysis showed that robotic gastrectomy is a safe technique for treating gastric cancer that compares favorably with laparoscopic gastrectomy in short term outcomes. However, the long term outcomes between the two techniques need to be further examined.

X-ray irradiation promotes apoptosis of hippocampal neurons through up-regulation of Cdk5 and p25.

BACKGROUND: Cranial radiation therapy has been used for the treatment of primary and metastatic brain tumors. A prominent feature of brain injury induced by the radiation therapy is hippocampal dysfunction, characterized by a decline in memory. Cdk5 plays an important role in memory formation. Abnormal Cdk5 activity is associated with neuronal apoptosis induced by neurotoxic stimuli. However, the roles of Cdk5 in hippocampal apoptosis in response to X-ray irradiation have not been explored. METHODS: The expression of Cdk5 activators, p35 and p25, in hippocampal neurons was tested in both in vivo animal and in vitro couture after X-ray irradiation. RESULTS: After X-ray irradiation at 20 Gy and 30 Gy in rats, the number of hippocampal neuronal pyknosis was increased, but the number of hippocampal neuron was decreased, in the hippocampal CA1 region of rats. In these animals undergone with X-ray irradiation, the expression of p35 was significantly down-regulated, but it was up-regulated in p25. These opposite expressions were also shown in the primary cultured hippocampal neurons with 30 Gy irradiation. The apoptosis induced by X-ray irradiation were significantly prevented by the pretreatment of Cdk5 inhibitor, roscovitine, in both in vivo and in vitro settings. CONCLUSIONS: X-ray irradiation resulted in a hippocampal neuronal apoptosis through up-regulation of p25, the Cdk5 activator. Hyperactivity of Cdk5 was involved in the pathogenesis of X-ray irradiation-induced hippocampal neuronal apoptosis. Blockade of Cdk5 signal pathway effectively protected neurons from the irradiation-induced brain injury.

Activation of AKT is associated with metastasis of nasopharyngeal carcinoma.

Although radiotherapy results of nasopharyngeal carcinoma (NPC) at an early stage are better than other tumors, there is still a portion of patients with NPC who die before 5 years after the treatment; the underlying mechanism remains to be further understood. This study aims to investigate the mechanism by which NPC cells escape from irradiation. Patients with NPC at stage I was included in this study. All the patients were treated with irradiation. NPC biopsies were obtained from each patient before and 1 week after the start of radiotherapy. Expression of AKT in NPC tissue was assessed by Western blotting. NPC cell line, SUNE-1 cells, was treated with irradiation. The levels of AKT in SUNE-1 cells were also assessed. The frequency of apoptotic SUNE-1 cells was evaluated by flow cytometry. The levels of AKT were markedly increased in NPC tissue after treatment with irradiation, which was significantly correlated with NPC metastasis and mortality. After irradiation, NPC cell line, SUNE-1 cells, expressed higher levels of AKT than control cells. The knockdown of AKT in SUNE-1 cells markedly increased apoptotic cell rate. Radiotherapy can increase the levels of AKT in NPC cells that are associated with NPC metastasis and increase in mortality.