Development of a rapid screening method utilizing 2D LC for effect-directed analysis in the identification of environmental toxicants.

Effect-directed analysis (EDA) is a crucial tool in environmental toxicology, effectively integrating toxicity testing with chemical analysis. The conventional EDA approach, however, presents challenges such as significant solvent consumption, extended analysis time, labor intensity, and potential contamination risks. In response, we introduce an innovative alternative to the conventional EDA. This method utilizes the MTT bioassay and online two-dimensional liquid chromatography (2D LC) coupled with high-resolution mass spectrometry (HR-MS), significantly reducing the fractionation steps and leveraging the enhanced sensitivity of the bioassay and automated chemical analysis. In the chemical analysis phase, a switching valve interface is employed for comprehensive analysis. We tested the performance of both the conventional and our online 2D LC-based methods using a household product. Both methods identified the same number of toxicants in the sample. Our alternative EDA is 22.5 times faster than the conventional method, fully automated, and substantially reduces solvent consumption. This novel approach offers ease, cost-effectiveness, and represents a paradigm shift in EDA methodologies. By integrating a sensitive bioassay with online 2D LC, it not only enhances efficiency but also addresses the challenges associated with traditional methods, marking a significant advancement in environmental toxicology research.

Unveiling genetics of non-syndromic albinism using whole exome sequencing: A comprehensive study of TYR, TYRP1, OCA2 and MC1R genes in 17 families.

BACKGROUND: Oculocutaneous albinism (OCA) is a group of skin depigmentation disorders. Clinical presentation of OCA includes defects in melanocyte differentiation, melanin biosynthesis, and melanosome maturation and transport. OBJECTIVES: A molecular diagnostics study of families presenting oculocutaneous albinism. METHODS: In this study, 17 consanguineous OCA families consisting of 93 patients were investigated. Whole Exome Sequencing (WES) of the index patient in each family were performed. Short listed variants of WES were Sanger validated for Mendelian segregation in obligate carriers and other available family members. Variant prioritization and pathogenicity were classified as per the criteria of American College Medical Genetics and Genomics (ACMG). Comparative computational modelling was performed to predict the potential damaging effect of the altered proteins. RESULTS: 15 pathogenic variations: c.132 T > A, c.346C > T, c.488C > G, c.1037G > A in TYR, c.1211C > T, c.1441G > A, c.1706_1707insT, c.2020C > G, c.2402G > C, c.2430del, in OCA2, c.1067G > A in TYRP1 and c.451C > T, c.515G > T, c.766C > T, c.917G > A in MC1R genes were identified. Three variants in OCA2 gene were characterized: c.1706_1707insT, c.2430del, and c.2402G > C, all of which were not reported before in OCA families. CONCLUSION: A few studies focusing on mutation screening of OCA patients have been reported before; however, this study has uniquely presents the Pakhtun ethnic population residing on the North-Western boarder. It explains that TYR, OCA2, TYRP1, and MC1R variations lead to non-syndromic OCA phenotype The overlapping phenotypes of OCA can precisely be diagnosed for its molecular pathogenicity using WES. This study recommends WES as a first-line molecular diagnostic tool, and provides a basis for developing customized genetic tests i.e. pre-marital screening to reduce the disease burden in the future generations.

The role of capecitabine-based neoadjuvant and adjuvant chemotherapy in early-stage triple-negative breast cancer: a systematic review and meta-analysis.

BACKGROUND: The role of capecitabine in neoadjuvant and adjuvant chemotherapy for early-stage triple-negative breast cancer (TNBC) is highly controversial. Our meta-analysis was designed to further elucidate the effects of capecitabine on survival in early-stage TNBC patients and its safety. METHODS: PubMed, Embase, and papers presented at several main conferences were searched up to December 19, 2019, to investigate capecitabine-based versus capecitabine-free neoadjuvant and adjuvant chemotherapy in TNBC patients. Heterogeneity was assessed using I2 test, combined with hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CI) computed for disease-free survival (DFS), overall survival (OS), and over grade 3 adverse events (AEs). RESULTS: A total of 9 randomized clinical trials and 3842 TNBC patients were included. Overall, the combined capecitabine regimens in neoadjuvant and adjuvant chemotherapy showed significantly improved DFS (HR = 0.75; 95% CI, 0.65-0.86; P < 0.001) and OS (HR = 0.63; 95% CI, 0.53-0.77; P < 0.001). In subgroup analysis, there were improvements in DFS in the groups with addition of capecitabine (HR = 0.64; 95% CI, 0.53-0.78; P < 0.001), adjuvant chemotherapy (HR = 0.73; 95% CI, 0.63-0.85; P < 0.001), and lymph node positivity (HR = 0.62; 95% CI, 0.44-0.86; P = 0.005). Capecitabine regimens were related to higher risks of diarrhea (OR = 2.88, 95% CI 2.23-3.74, P < 0.001), stomatitis (OR = 2.01, 95% CI 1.53-2.64, P < 0.001) and hand-foot syndrome (OR = 8.67, 95% CI 6.70-11.22, P < 0.001). CONCLUSION: This meta-analysis showed that neoadjuvant and adjuvant chemotherapy combined with capecitabine significantly improved both DFS and OS in early-stage TNBC patients with tolerable AEs. There were benefits to DFS in the groups with the addition of capecitabine, adjuvant chemotherapy, and lymph node positivity.

Toxicity of extended adjuvant endocrine with aromatase inhibitors in patients with postmenopausal breast cancer: A Systemtic review and Meta-analysis.

BACKGROUND: Extended endocrine therapy (EET) with aromatase inhibitors (AIs) therapy can further reduce the risk of recurrence in breast cancer patients. But the conclusion that whether EET with AIs increases the risk of some side effects compared with nonextended endocrine therapy (NEET) is still controversial and not exhaustive. METHODS: We searched for Randomized controlled trials (RCT) trials published in EMBASE and PubMed between March 2008 and December 2019. Studies comparing the side effects of adjuvant EET with those of NEET were included. The objective was to determine whether EET with AIs increases the risk of side effects compared with NEET. RESULTS: Overall, 11 trials comprising 24,187 participants were identified. EET with AIs increased the risk of cardiotoxicity [odds ratio (OR) 1.19, 95 % confidence interval (CI) 1.04-1.36; P < 0.05; 438 vs 423], bone pain (OR 1.18, 95 % CI 1.02-1.36; P < 0.05; 446 vs 404), osteoporosis (OR 1.53, 95 % CI 1.35-1.72; P < 0.05; 866 vs 641), fractures (OR 1.33, 95 % CI 1.18-1.50; P < 0.05; 596 vs 438), arthralgia (OR 1.27, 95 % CI 1.19-1.36; P < 0.05; 2404 vs 2060), myalgia (OR 1.29, 95 % CI 1.16-1.43; P < 0.05; 960 vs 776), and hot flashes (OR 1.40, 95 % CI 1.15-1.69; P < 0.05; 2418 vs 2174) and was associated with opposite risk of vaginal bleeding (OR 0.74, 95 % CI 0.59-0.92; P < 0.05; 148 vs 197). However, the extended therapy did not increase the risk of hypertension (OR 1.03, 95 % CI 0.80-1.33; P = 0.80; 364 vs 353), hypercholesterolemia (OR 1.03, 95 % CI 0.91-1.16; P = 0.62; 643 vs 627), vaginal dryness (OR 1.19, 95 % CI 1.00-1.42; P = 0.05; 294 vs 257), fatigue (OR 1.20, 95 % CI 0.96-1.50; P = 0.12; 1501 vs 1462), dizziness (OR 1.04, 95 % CI 0.92-1.17; P = 0.55; 614 vs 595), headaches (OR 1.06, 95 % CI 0.95-1.18; P = 0.30; 885 vs 848), constipation (OR 0.91, 95 % CI 0.79-1.04; P = 0.15; 480 vs 522), nausea (OR 1.83, 95 % CI 0.49-6.83; P =0.37; 340 vs 325), and dyspnea (OR 0.96, 95 % CI 0.82-1.13; P = 0.64; 340 vs 351). The risk of grade ≥ 3 hot flashes increased following extended endocrine therapy (OR 2.01, 95 % CI 1.23-3.29; P < 0.05; 47 vs 23). We observed no evidence for a difference in the risk of grade ≥3 fatigue, arthralgia, myalgia, bone pain, osteoporosis, fractures, hypertension, and headache between both endocrine therapies. Secondary outcomes shows that after receive EET with AIs, patients can benefit from the control of the local recurrence, distant recurrence, contralateral breast cancer, and second cancers. CONCLUSIONS: Compared with NEET, EET with AIs significantly increased the risk of cardiotoxicity, bone pain, osteoporosis, fractures, hot flashes, arthralgia, myalgia, and grade ≥3 hot flashes, and EET with AIs can reduced the risks of local recurrence, distant recurrence, contralateral breast cancer, and second cancers. These findings offer an important guide for clinicians and patients.

Association of Cyclin-Dependent Kinases 4 and 6 Inhibitors With Survival in Patients With Hormone Receptor-Positive Metastatic Breast Cancer: A Systematic Review and Meta-analysis.

Importance: One of the most recent treatment regimens used for hormone receptor (HR)-positive, ERBB2 (formerly HER2)-negative metastatic breast cancer is treatment with the cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors and endocrine therapy (ET). Objective: To assess overall survival (OS), progression-free survival (PFS), objective response rate, and adverse events, especially grades 3 and 4 adverse events, among patients with HR-positive, ERBB2-negative metastatic breast cancer who were treated with CDK4/6 inhibitors plus ET vs ET alone. Data Sources: A systematic search of PubMed, Embase, the main oncology conference of the European Society of Medical Oncology, and the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium databases for randomized clinical trials of CDK4/6 inhibitors plus ET vs ET for HR-positive, ERBB2-negative metastatic breast cancer. Searches were performed up to March 30, 2020. Study Selection: A total of 472 records were assessed in PubMed and Embase by 2 authors, including studies, international meeting reports, and reviews. Inclusion criteria were English-language phase 2 or 3 randomized clinical trials of HR-positive, ERBB2-negative metastatic breast cancer, with patients randomly assigned to receive CDK4/6 inhibitors plus ET or ET alone, and having OS or PFS outcomes. The exclusion criteria were phase 1 trials, retrospective studies, or studies without survival outcomes. Excluding the references, 16 articles were relevant. After excluding studies based on exclusion criteria, 9 studies were considered eligible for this meta-analysis. Data Extraction and Synthesis: Two researchers independently extracted data and assessed potential bias. Data assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. The results were pooled using a fixed-effect model. Main Outcomes and Measures: Study heterogeneity was assessed using the I2 statistic. Hazard ratios (HRs) and 95% CIs were used to evaluate PFS, OS, and subgroup analyses. Overall response and 95% CIs were used to evaluate the objective response rate and grade 3 or 4 adverse events. The primary outcome was OS. Results: In total, 9 studies that included a total of 5043 patients with metastatic breast cancer were assessed in this meta-analysis. Overall, the addition of CDK4/6 inhibitors to ET was associated with a statistically significant benefit to OS (HR, 1.33; 95% CI, 1.19-1.48; P < .001). Compared with ET alone, treatment with CDK4/6 inhibitors plus ET was associated with improved OS for the following subgroups: first-line therapy (HR, 1.35; 95% CI, 1.18-1.54; P < .001), second-line therapy (HR, 1.30; 95% CI, 1.09-1.54; P < .001), premenopausal women (HR, 1.32; 95% CI, 1.04-1.66; P < .001), postmenopausal women (HR, 1.34; 95% CI, 1.18-1.52; P < .001), visceral metastasis (HR, 1.31; 95% CI, 1.12-1.53; P < .001), bone-only metastasis (HR, 1.22; 95% CI, 0.88-1.68; P < .001), age younger than 65 years (HR, 1.25; 95% CI, 1.06-1.49; P < .001), and age 65 years or older (HR, 1.38; 95% CI, 1.11-1.72; P < .001). The addition of CDK4/6 inhibitors to ET was also associated with significant PFS benefit (HR, 1.84; 95% CI, 1.70-1.98; P < .001) and objective response rate benefit (odds ratio, 2.02; 95% CI, 1.61-2.53; P < .001). However, the use of CDK4/6 inhibitors in combination with ET was associated with significantly increased risk of grade 3 or 4 adverse events compared with ET alone, including neutropenia (HR, 57.05; 95% CI, 38.26-85.05; P < .001), leukopenia (HR, 36.36; 95% CI, 19.35-68.34; P < .001), and diarrhea (HR, 4.97; 95% CI, 2.84-8.69; P < .001). Conclusions and Relevance: This meta-analysis indicated that, compared with ET alone, treatment with CDK4/6 inhibitors plus ET was associated with significantly improved OS, PFS, and objective response rate among patients with HR-positive, ERBB2-negative metastatic breast cancer.

Characterization of native plant growth promoting rhizobacteria and their anti-oomycete potential against Phytophthora capsici affecting chilli pepper (Capsicum annum L.).

Phytophthora capsici is a notorious fungus which infects many crop plants at their early and late growth stages. In the present study, twelve P. capsici isolates were morphologically characterized, and based on pathogenicity assays; two highly virulent isolates causing post-emergence damping-off on locally cultivated chilli pepper were screened. Two P. capsici isolates, HydPak1 (MF322868) and HydPk2 (MF322869) were identified based on internal transcribed spacer (ITS) sequence homology. Plant growth promoting rhizobacteria (PGPR) play a significant role in disease suppression and plant growth promotion in various crops. Out of fifteen bacterial strains recovered from chilli rhizosphere, eight were found potential antagonists to P. capsici in vitro. Bacterial strains with strong antifungal potential were subjected to biochemical and molecular analysis. All tested bacterial strains, were positive for hydrogen cyanide (HCN), catalase production and indole-3-acetic acid (IAA) production (ranging from 6.10 to 56.23 µg ml-1), while siderophore production varied between 12.5 and 33.5%. The 16S rRNA sequence analysis of tested bacterial strains showed 98-100% identity with Pseudomonas putida, P. libanensis, P. aeruginosa, Bacillus subtilis, B. megaterium, and B. cereus sequences available in the National Center for Biotechnology Information (NCBI) GenBank nucleotide database. All sequences of identified bacteria were submitted to GenBank for accessions numbers (MH796347-50, MH796355-56, MH801129 and MH801071). Greenhouse studies concluded that all tested bacterial strains significantly suppressed the P. capsici infections (52.3-63%) and enhanced the plant growth characters in chilli pepper. Efficacy of many of these tested rhizobacteria is being first time reported against P. capsici from Pakistan. Plant growth promoting rhizobacteria (PGPR) exhibiting multiple traits may be used in the development of new, eco-friendly, and effective bioformulations as an alternative to synthetic fungicides.

A comparison between triplet and doublet chemotherapy in improving the survival of patients with advanced gastric cancer: a systematic review and meta-analysis.

BACKGROUND: Chemotherapy can improve the survival of patients with advanced gastric cancer. However, whether triplet chemotherapy can further improve the survival of patients with advanced gastric cancer compared with doublet chemotherapy remains controversial. This study reviewed and updated all published and eligible randomized controlled trials (RCTs) to compare the efficacy, prognosis, and toxicity of triplet chemotherapy with doublet chemotherapy in patients with advanced gastric cancer. METHODS: RCTs on first-line chemotherapy in advanced gastric cancer on PubMed, Embase, and the Cochrane Register of Controlled Trials and all abstracts from the annual meetings of the European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology conferences up to October 2018 were searched. The primary outcome was overall survival, while the secondary outcomes were progression-free survival (PFS), time to progress (TTP), objective response rate (ORR), and toxicity. RESULTS: Our analysis included 23 RCTs involving 4540 patients and 8 types of triplet and doublet chemotherapy regimens, and systematic review and meta-analysis revealed that triplet chemotherapy was superior compared with doublet chemotherapy in terms of improving median OS (HR = 0.92; 95% CI, 0.86-0.98; P = 0.02) and PFS (HR = 0.82; 95% CI, 0.69-0.97; P = 0.02) and TTP (HR = 0.92; 95% CI, 0.86-0.98; P = 0.02) and ORR (OR = 1.21; 95% CI, 1.12-1.31; P < 0.0001) among overall populations. Compared with doublet chemotherapy, subgroup analysis indicated that OS improved with fluoropyrimidine-based (HR = 0.80; 95% CI, 0.66-0.96; P = 0.02), platinum-based (HR = 0.75; 95% CI, 0.57-0.99; P = 0.04), and other drug-based triplet (HR = 0.79; 95% CI, 0.69-0.90; P = 0.0006) chemotherapies while not with anthracycline-based (HR = 0.70; 95% CI, 0.42-1.15; P = 0.16), mitomycin-based (HR = 0.81; 95% CI, 0.47-1.39; P = 0.44), taxane-based (HR = 0.91; 95% CI, 0.81-1.01; P = 0.07), and irinotecan-based triplet (HR = 1.01; 95% CI, 0.82-1.24; P = 0.94) chemotherapies. For different patients, compared with doublet chemotherapy, triplet chemotherapy improved OS (HR = 0.89; 95% CI, 0.81-0.99; P = 0.03) among Western patients but did not improve (HR = 0.96; 95% CI, 0.86-1.07; P = 0.47) that among Asian patients. CONCLUSIONS: Compared with doublet chemotherapy, triplet chemotherapy improved OS, PFS, TTP, and ORR in patients with advanced gastric cancer in the population overall, and improved OS in Western but not in Asian patients.

Predicting the Efficacy of 5-Fluorouracil-Based Adjuvant Chemotherapy in Gastric Cancer by Microsatellite Instability: A Meta-Analysis.

Microsatellite instability (MSI) implies the deletion of mismatch repair genes caused by DNA methylation or gene mutation. MSI is a good predictor for efficacy of 5-fluorouracil (FU)-based chemotherapy in the treatment of colorectal cancer. Some gastric cancer studies have reported that MSI has no apparent impact on prognosis after patients receive 5-FU-based adjuvant chemotherapy. However, other studies suggest that high-frequency MSI (MSI-H) status reduced survival in patients receiving 5-FU-based adjuvant chemotherapy. Thus, the correlation between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer remains controversial. We performed a PubMed, Embase, and Cochrane search to retrieve studies that explore the correlation between MSI status and 5-FU-based adjuvant chemotherapy efficacy in gastric cancer. After extracting 65 potentially eligible studies, four were ultimately included in this meta-analysis using Stata software (ver. 12.0). For each study, we estimated the hazard ratio (HR) value for overall survival (OS), and HR was extracted per the survival curve in the studies. Heterogeneity was estimated using the random-effects model. Overall, 1174 patients after operation were included: 84 patients were classed as MSI-H and 1090 as microsatellite stable (MSS)/low-frequency MSI (MSI-L). For the four studies, the overall estimate of HR for OS between MSI-H and MSS/MSI-L groups was 1.90 (95% confidence interval: 0.91-3.93; p = 0.08). We found no correlation to exist between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer. Although MSI can effectively predict efficacy of 5-FU-based chemotherapy in patients with colorectal cancer, the correlation between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer remains controversial. This meta-analysis suggests that MSI status is unrelated to efficacy of 5-FU-based adjuvant chemotherapy in gastric cancer, and more prospective clinical studies are needed to further investigate predictive value of MSI status in patients with gastric cancer who, after operation, receive 5-FU-based adjuvant chemotherapy.

Adjuvant chemotherapy with S-1 plus oxaliplatin improves survival of patients with gastric cancer after D2 gastrectomy: A multicenter propensity score-matched study.

AIM: To investigate the safety and efficacy of S-1 plus oxaliplatin (SOX) as an adjuvant chemotherapy regimen in gastric cancer (GC) after D2 dissection. METHODS: GC Patients who underwent D2 gastrectomy from September 2009 to December 2011 in four Chinese institutions were enrolled. Patients with stage IB-IIIC GC, who received adjuvant SOX treatment were matched by propensity scores with those who underwent surgery alone and those who conducted capecitabine plus oxaliplatin (XELOX) regimen. Disease-free survival (DFS) and overall survival (OS) were compared among the groups. In addition, adverse events in SOX patients were analyzed. RESULTS: Of 1944 GC patients who underwent D2 dissection, 867 were included for analysis. One hundred and seventeen patients treated with SOX were matched to 234 patients who conducted surgery alone. Fifty-seven patients treated with SOX were matched to 57 patients who received XELOX. The estimated five-year DFS was 57.5% in the adjuvant SOX group which was higher than that (44.6%) in the surgery alone group (P = 0.001); and the estimated five-year OS was 68.3% which was higher than that (45.8%) of surgery alone group (P < 0.001). Survival benefit was also revealed in stage III and > 60 years old subgroups (P < 0.001 and P = 0.015, respectively). Compared with XELOX regimen, SOX showed no significant difference in DFS (P = 0.340) and OS (P = 0.361). The most common ≥ 3 grade adverse events of SOX regimen were neutropenia (22.6%), leukopenia (8.9%) and thrombocytopenia (5.6%). CONCLUSION: Compared with surgery alone, SOX regimen significantly improves the long-term survival and has acceptable toxicity in patients with stage IB-IIIC GC after D2 dissection. It may be a novel adjuvant chemotherapy regimen in GC patients.

Anlotinib: a novel multi-targeting tyrosine kinase inhibitor in clinical development.

Anlotinib is a new, orally administered tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor (VEGFR), fibroblast growth factor receptor (FGFR), platelet-derived growth factor receptors (PDGFR), and c-kit. Compared to the effect of placebo, it improved both progression-free survival (PFS) and overall survival (OS) in a phase III trial in patients with advanced non-small-cell lung cancer (NSCLC), despite progression of the cancer after two lines of prior treatments. Recently, the China Food and Drug Administration (CFDA) approved single agent anlotinib as a third-line treatment for patients with advanced NSCLC. Moreover, a randomized phase IIB trial demonstrated that anlotinib significantly prolonged the median PFS in patients with advanced soft tissue sarcoma (STS). Anlotinib also showed promising efficacy in patients with advanced medullary thyroid carcinoma and metastatic renal cell carcinoma (mRCC). The tolerability profile of anlotinib is similar to that of other tyrosine kinase inhibitors that target VEGFR and other tyrosine kinase-mediated pathways; however, anlotinib has a significantly lower incidence of grade 3 or higher side effects compared to that of sunitinib. We review the rationale, clinical evidence, and future perspectives of anlotinib for the treatment of multiple cancers.

Clinicopathological Characteristics and Prognoses of Elderly Gastric Cancer Patients after R0 Resection: A Multicenter Study in China.

The number of elderly gastric cancer (GC) patients has been rapidly increasing worldwide, but inadequate understanding regarding elderly GC patients has led to the paucity of appropriate treatment decisions. Our study evaluates clinicopathological characteristics and prognoses of elderly GC patients after R0 resection. Overall, 1877 consecutive GC patients who underwent R0 gastrectomy at four centers were enrolled. We divided patients into three groups according to age: young, middle, and elderly. We then analyzed clinicopathological characteristics and prognoses. Compared to the middle-aged group, the elderly group had a higher male-to-female ratio and number of patients with cardiac GC, trend of more advanced pathological stage, lower ratio of poor to moderate tumor grade, and fewer patients who received adjuvant chemotherapy or chemoradiotherapy. Moreover, 5 yr disease-free survival and overall survival rates of elderly patients were significantly less than those of middle-aged patients. A Cox analysis of middle-aged and elderly patients revealed that age and adjuvant chemotherapy were independent prognostic factors. Adjuvant chemotherapy improved long-term survival of elderly patients with stage III cancer. Elderly GC patients who underwent R0 resection had unique characteristics and poor long-term survival. We found that subjects should be stratified into the three aforementioned age groups when analyzing survival rates of GC patients. In addition, reasonable adjuvant treatment is recommended for elderly patients.

Novel fluoropyrimidine-based chemotherapy for advanced well-differentiated neuroendocrine tumors: a clinical update.

INTRODUCTION: Patients with advanced well-differentiated neuroendocrine tumors (NETs) who have bulky and/or symptomatic and/or rapidly progressive disease require chemotherapy treatment. AREAS COVERED: This review summarizes the accumulating evidence for treatment with fluorouracil-based chemotherapy in well-differentiated NETs. The main clinical studies, toxicity and predictors of fluorouracil- based chemotherapy regimens in well-differentiated NETs are discussed, along with the current issues, future research directions and therapeutic prospects. EXPERT OPINION: Somatostatin analogs may control symptoms of hormone excess and tumor growth in patients with well-differentiated metastatic NETs, and biological therapies may improve progression-free survival for these patients. However, chemotherapy leads to higher objective response rates and symptom control by reducing tumor bulk. The low response rate and significant toxicities of conventional chemotherapy regimens limit their widespread use. Fortunately, some novel fluoropyrimidine-based treatment including fluorouracil, capecitabine, or S-1 based chemotherapy with or without antiangiogenic agents have been investigated in recent years. These treatments showed significant efficacy and less toxicity in pancreatic and non-pancreatic metastatic well-differentiated NETs. Additionally, non-pancreatic well-differentiated NETs have also achieved similar tumor response or survival comparable to pancreatic NETs. Moreover, some predictors of response to these treatment regimens have been evaluated.