Growth differentiation factor 15 induces cisplatin resistance through upregulation of xCT expression and glutathione synthesis in gastric cancer.

Gastric cancer is a common cancer worldwide, particularly in East Asia. Chemotherapy is used in adjuvant or palliative therapies for gastric cancer. However, subsequent chemoresistance often develops. Growth differentiation factor 15 (GDF15) links to several cancers, but its effect on chemoresistance in gastric cancer remains unclear. Here, we analyzed clinical samples from genetic databases and included patients with gastric cancer. We dissected the regulatory mechanism underlying GDF15-mediated resistance of cisplatin in human gastric cancer cells. We showed that GDF15 serum levels might be a valuable biomarker for predicting prognosis in gastric cancer. The expressions of GDF15 and its receptor glial cell-derived neurotrophic factor family receptor a-like (GFRAL) in gastric tumors are important for malignant progression. Moreover, GDF15 expression is increased in gastric cancer cells with cisplatin resistance, resulting from elevated intracellular glutathione (GSH) and antioxidant activities. Upregulated GDF15 could increase intracellular GSH content by activating the GFRAL-GCN2-eIF2α-ATF4 signaling, enhancing cystine-uptake transporter xCT expression, and contributing biosynthesis of GSH in human gastric cancer cells. In conclusion, our results indicate that GDF15 could induce chemoresistance by upregulating xCT expression and GSH biosynthesis in human gastric cancer cells. Targeting GDF15 could be a promising treatment method for gastric cancer progression.

Mapping a Circular RNA-microRNA-mRNA-Signaling Regulatory Axis That Modulates Stemness Properties of Cancer Stem Cell Populations in Colorectal Cancer Spheroid Cells.

Spheroidal cancer cell cultures have been used to enrich cancer stem cells (CSC), which are thought to contribute to important clinical features of tumors. This study aimed to map the regulatory networks driven by circular RNAs (circRNAs) in CSC-enriched colorectal cancer (CRC) spheroid cells. The spheroid cells established from two CRC cell lines acquired stemness properties in pluripotency gene expression and multi-lineage differentiation capacity. Genome-wide sequencing identified 1503 and 636 circRNAs specific to the CRC parental and spheroid cells, respectively. In the CRC spheroids, algorithmic analyses unveiled a core network of mRNAs involved in modulating stemness-associated signaling pathways, driven by a circRNA-microRNA (miRNA)-mRNA axis. The two major circRNAs, hsa_circ_0066631 and hsa_circ_0082096, in this network were significantly up-regulated in expression levels in the spheroid cells. The two circRNAs were predicted to target and were experimentally shown to down-regulate miR-140-3p, miR-224, miR-382, miR-548c-3p and miR-579, confirming circRNA sponging of the targeted miRNAs. Furthermore, the affected miRNAs were demonstrated to inhibit degradation of six mRNA targets, viz. ACVR1C/ALK7, FZD3, IL6ST/GP130, SKIL/SNON, SMAD2 and WNT5, in the CRC spheroid cells. These mRNAs encode proteins that are reported to variously regulate the GP130/Stat, Activin/Nodal, TGF-ß/SMAD or Wnt/ß-catenin signaling pathways in controlling various aspects of CSC stemness. Using the CRC spheroid cell model, the novel circRNA-miRNA-mRNA axis mapped in this work forms the foundation for the elucidation of the molecular mechanisms of the complex cellular and biochemical processes that determine CSC stemness properties of cancer cells, and possibly for designing therapeutic strategies for CRC treatment by targeting CSC.

Comparison of the Clinicopathological Characteristics and Genetic Alterations Between Patients with Gastric Cancer with or Without Helicobacter pylori Infection.

BACKGROUND: Helicobacter pylori (HP) can induce epithelial cells and intestinal metaplasia with genetic damage that makes them highly susceptible to the development of gastric cancer (GC). MATERIALS AND METHODS: Between 2005 and 2010, 356 patients with gastric cancer who received curative surgery were enrolled. Analysis of HP, Epstein-Barr virus (EBV) infection, PIK3CA amplification, and mutation analysis of 68 mutations in eight genes using a mass spectrometric single-nucleotide polymorphism genotyping technology was conducted. The clinicopathological characteristics of patients with or without HP infection were compared. RESULTS: Among the 356 patients, 185 (52.0%) had HP infection. For intestinal-type GC, patients with HP infection were more likely to be younger and had fewer PI3K/AKT pathway genetic mutations than those without HP infection. For diffuse-type GC, patients with HP infection were characterized by less male predominance, less lymphoid stroma, fewer microsatellite instability-high tumors, and fewer PI3K/AKT pathway genetic mutations than those without HP infection. Patients with HP infection had less tumor recurrence and a better 5-year overall survival (87.7% vs. 73.9%, p = .012) and disease-free survival (64.1% vs. 51.3%, p = .013) than those without HP infection, especially for intestinal-type GC. For EBV-negative GC, patients with HP infection had fewer PI3K/AKT pathway mutations and a better 5-year overall survival and disease-free survival than those without HP infection. Multivariate analysis demonstrated that HP infection was an independent prognostic factor regarding overall survival and disease-free survival. CONCLUSION: Patients with GC with HP infection were associated with fewer PI3K/AKT pathway genetic mutations and better survival than those without HP infection, especially for EBV-negative and intestinal-type GC. IMPLICATIONS FOR PRACTICE: Patients with gastric cancer with Helicobacter pylori (HP) infection had fewer PI3K/AKT pathway genetic mutations, less tumor recurrence, and better survival than those without HP infection, especially for Epstein-Barr virus (EBV)-negative and intestinal-type gastric cancer. HP infection is an independent prognostic factor regarding overall survival and disease-free survival. Future in vivo and in vitro studies of the correlation among HP infection, PI3K/AKT pathway, and EBV infection in gastric cancer are required.

Clinicopathological differences in signet ring cell adenocarcinoma between early and advanced gastric cancer.

BACKGROUND: Signet ring cell adenocarcinoma is a histological classification based on the WHO classification. The presence of this specific histological type is associated with a worse pathological appearance. The prognosis of signet ring cell adenocarcinoma in gastric cancer patients after curative surgery is still under debate. METHODS: From January 1988 to December 2012, a total of 2971 patients, including 819 early and 2152 advanced gastric cancer patients underwent curative resection for gastric cancer. Among them, there were 185 cases of signet ring cell adenocarcinoma in early gastric cancer patients, while there were 570 cases in advanced gastric cancer patients. RESULTS: The overall incidence of signet ring cell adenocarcinoma was 25.4%. Our results showed that the 5-year overall survival rates of early gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 90.7 and 83.2%, respectively (P = 0.001). The 5-year disease-free survival rates of early gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 87.4 and 81.6%, respectively (P = 0.003). The 5-year overall survival rates of advanced gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 32.1 and 37.9%, respectively (P = 0.041). The 5-year disease-free survival rates of advanced gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 28.6 and 35.2%, respectively (P = 0.037). Signet ring cell adenocarcinoma was an independent predictor for overall survival in advanced gastric cancer (P = 0.017). CONCLUSION: The clinical features and prognosis of signet ring cell adenocarcinoma are different between early and advanced gastric cancer. Signet ring cell adenocarcinoma is a poor prognostic factor in advanced gastric cancer after curative resection.

Does a Higher Cutoff Value of Lymph Node Retrieval Substantially Improve Survival in Patients With Advanced Gastric Cancer?-Time to Embrace a New Digit.

BACKGROUND: The present study assessed the impact of the retrieval of >25 lymph nodes (LNs) on the survival outcome of patients with advanced gastric cancer after curative-intent gastrectomy. PATIENTS AND METHODS: A total of 5,386 patients who had undergone curative gastrectomy for gastric cancer from 1994 to 2011 were enrolled. The clinicopathological parameters and overall survival (OS) were analyzed according to the number of LNs examined (≤15, n = 916; 16-25, n = 1,458; and >25, n = 3,012). RESULTS: The percentage of patients with >25 LNs retrieved increased from 1994 to 2011. Patients in the LN >25 group were more likely to have undergone total gastrectomy and to have a larger tumor size, poorer tumor differentiation, and advanced T and N stages. Hospital mortality among the LN ≤15, LN 16-25, and LN >25 groups was 6.1%, 2.7%, and 1.7%, respectively (p < .0001). The LN >25 group consistently exhibited the most favorable OS, in particular, with stage II disease (p = .011) when OS was stratified according to tumor stage. Similarly, the LN >25 group had significantly better OS in all nodal stages (from N1 to N3b). The discrimination power of the lymph node ratio (LNR) for the LN ≤15, LN 16-25, and LN >25 groups was 483, 766, and 1,560, respectively. Multivariate analysis demonstrated that the LNR was the most important prognostic factor in the LN >25 group. CONCLUSION: Retrieving more than 25 lymph nodes during curative-intent gastrectomy substantially improved survival and survival stratification of advanced gastric cancer without compromising patient safety. The Oncologist 2017;22:97-106Implications for Practice: D2 lymph node (LN) dissection is currently the standard of surgical management of gastric cancer, which is rarely audited by a third party. The present study, one of the largest surgical series worldwide, has shown that the traditionally recognized retrieval of ≥16 LNs during curative-intent gastrectomy might not be adequate in regions in which locally advanced gastric cancers predominate. The presented data show that retrieval of >25 LNs, which more greatly mimics D2 dissection, improves long-term outcomes and survival stratification without compromising patient safety.

Comparison of the surgical outcomes of minimally invasive and open surgery for octogenarian and older compared to younger gastric cancer patients: a retrospective cohort study.

BACKGROUND: As life expectancy continues to increase around the world, the use of minimally invasive surgery (MIS) could be beneficial for octogenarian and older gastric cancer patients. METHODS: A total of 359 gastric cancer patients who underwent curative surgery between March 2011 and March 2015 were enrolled; 80 of these patients (22.2%) were octogenarians and older. Surgical approaches included MIS (50 laparoscopic and 65 robotic) and open surgery (n = 244). Surgical outcomes of MIS and open surgery in octogenarian and older patients were compared with younger patients. RESULTS: Among octogenarian and older patients, relative to open surgery (n = 53), MIS (n = 27) was associated with less operative blood loss, a shorter postoperative hospital stay and similar rates of surgical complications and mortality. For MIS (n = 115), octogenarian and older patients exhibited similar postoperative outcomes to those of younger patients. For open surgery (n = 244), relative to younger patients, octogenarian and older patients experienced longer postoperative hospital stays, a higher rate of wound infection and a higher incidence of pneumonia. CONCLUSIONS: MIS for gastric cancer is beneficial and can be performed safely in octogenarian and older patients.

Clinical significance of circulating plasma DNA in gastric cancer.

With the progression of molecular techniques, the detection of circulating plasma DNA (cpDNA) is clinically feasible. However, the role of the cpDNA levels in gastric cancer is not well understood. This study assessed the mutational profile in primary tumors and clarified the clinical utility of quantitative and qualitative cpDNA alterations in 277 patients with advanced gastric cancer. The concentrations of cpDNA were measured by TaqMan qPCR, and 68 mutations in 8 genes were studied for cpDNA mutations. The median cpDNA concentrations in patients with stages I, II, and III gastric cancer were 3979, 3390 and 4278 copies/mL, respectively, and increased to 11,380 copies/mL in patients with Stage IV gastric cancer (p < 0.001). Among the 35 patients harboring cpDNA mutations, Stage IV patients (100%) were more likely to display high cpDNA levels than were Stage I (33.3%), II (75%) and III patients (66.7%) (p = 0.037). Patients displaying high cpDNA levels were more likely to experience peritoneal recurrence and exhibited significantly lower 5-year overall survival rates (39.2% vs. 45.8%, p = 0.039) than did patients displaying low cpDNA levels. Only for late stage (Stages III or IV) gastric cancer, patients harboring cpDNA mutations were more likely to experience vascular invasion (20% vs. 2.4%, p = 0.036) and exhibited a lower 5-year overall survival rate than did those lacking cpDNA mutations (5.6% vs. 31.5%, p = 0.028). High cpDNA levels are associated with peritoneal recurrence and poor prognosis in patients with advanced gastric cancer; harboring cpDNA mutations is associated with poor prognosis among patients with late stage gastric cancer.

The Correlation Between RhoA Expression and Clinicopathological Characteristics in Gastric Cancer Patients After Curative Surgery.

BACKGROUND: The expression of RhoA, a member of the ras homologue family, is reported to be involved in tumorigenesis in some cancers; however, its prognostic value in gastric cancer is controversial. METHODS: Between April 1988 and January 2005, a total of 206 gastric cancer patients receiving curative surgery were enrolled in this study. Immunohistochemical staining of the RhoA protein was performed, and the clinicopathological characteristics and initial recurrence patterns were compared between low RhoA expression (n = 55) and high RhoA expression (n = 151) gastric cancer patients. RESULTS: For intestinal-type (n = 134) gastric cancer, there is no significant difference between the clinicopathological characteristics and RhoA expression. However, for diffuse-type (n = 82) gastric cancer, high RhoA expression was associated with more advanced pathological N category compared to low RhoA expression. A multivariate analysis revealed that age, pathological T and N categories, and RhoA expression were independent prognostic factors for overall survival after curative surgery. For all patients, the five-year overall survival rates and disease-free survival rates were higher in patients with low RhoA expression compared to those with high RhoA expression, which was observed in diffuse-type gastric cancer, not in intestinal-type gastric cancer. With regard to the initial recurrence pattern, patients with high RhoA expression had more distant metastasis compared to those with low RhoA expression, especially more liver metastasis. CONCLUSIONS: RhoA expression is an independent prognostic factor for gastric cancer, especially for diffuse-type. We should be aware of liver metastasis during the follow-up of gastric cancer with high RhoA expression.

Outcome after curative surgery for gastric cancer patients with type 2 diabetes.

BACKGROUND: Bariatric surgery has been adapted to the management of morbid obesity, leading to not only loss of body weight but also improvement of type 2 diabetes mellitus (DM). The goal of our study was to evaluate the effect of gastrectomy in gastric cancer patients with type 2 DM. METHODS: From 1989 to 2011, a total of 69 gastric cancer patients receiving curative surgery were enrolled in this study. They were diagnosed with type 2 DM preoperatively and all are alive without tumor recurrence. The clinical characteristics were compared between groups with improved or unimproved DM, and groups were also analyzed based on the extent of gastrectomy and different reconstruction methods. RESULTS: Of the 69 patients, 58 received subtotal gastrectomy and 11 received total gastrectomy. The frequency of DM improvement was significantly higher after total gastrectomy than subtotal gastrectomy (81.8 vs. 36.2 %; p = 0.007). Patients with DM duration of less than 5 years tended to experience DM improvement after surgery more frequently than patients with DM duration of more than 5 years (p = 0.028). Roux-en-Y esophagojejunostomy (R-Ye) led to a higher rate of DM improvement than did R-Y gastrojejunostomy (R-Yg), especially in patients with DM duration more than 5 years. Among patients receiving duodenal bypass after gastrectomy, R-Ye was associated with a higher frequency of DM improvement than R-Yg and B-II. CONCLUSIONS: The extent of gastrectomy rather than the reconstruction method played an important role in DM improvement after curative surgery for gastric cancer.

SIRT3 expression as a biomarker for better prognosis in gastric cancer.

BACKGROUND: SIRT3-mitochondrial nicotinamide adenine dinucleotide-dependent deacetylase sirtuin-3-plays an important role in regulating cell metabolism and carcinogenesis. The role of SIRT3 in gastric cancer has not yet been investigated. METHODS: A total of 221 gastric cancer patients who underwent curative surgery were enrolled at the Department of Surgery, Taipei Veterans General Hospital. SIRT3 expression in gastric tissues and tumors were examined in these patients using immunohistochemical staining. Clinicopathologic characteristics and survival were analyzed and compared in gastric cancer patients with or without SIRT3 expression. RESULTS: The 5-year survival rates of patients with or without SIRT3 expression were 51.2 and 39.1 %, respectively (p = 0.005). The 5-year disease-free survival rates of patients with or without SIRT3 expression were 49.6 and 38.0 %, respectively (p = 0.010). Microscopic features showed that there are more poor cell differentiation (p = 0.001), more diffuse-type Lauren's histology (p = 0.018), and more scirrhous-type stromal reactions (p = 0.027) in gastric cancer without SIRT expression. Multivariate analysis with overall survival as an endpoint showed that age (p < 0.001), Lauren's histology (p = 0.007), stromal reaction (p = 0.035), TNM pathologic N category (p < 0.001), and SIRT3 expression (p < 0.001) were significantly correlated with gastric cancer. CONCLUSIONS: Gastric cancer patients with SIRT3 expression have a better prognosis than those without. SIRT3 expression is an independent prognostic marker for overall survival and may act as a tumor suppressor in gastric cancer.

The alteration of fecal microbial and metabolic profile of gallstone patients in Taiwan: Single-center study.

BACKGROUND: Gallstone disease is a common health problem worldwide. The role of the gut microbiota in gallstone pathogenesis remains obscure. Our aim was to evaluate the association and crosstalk between gut microbiota, gut metabolomic, and metabolic parameters in cholesterol gallstone patients, pigmented gallstone patients, and controls. METHODS: We collected stool samples from healthy individuals and patients with gallstones in our hospital from March 2019 to February 2021. 16s rRNA sequencing was performed, followed by differential abundance analyses. Measurement of bile acids and short-chain fatty acids was conducted via targeted metabolomics. RESULT: Thirty healthy individuals and 20 gallstone patients were recruited. The intergroup difference of microbial composition was significant between control and gallstone patients. The control group had more abundant Faecalibacterium , Prevotella 9 , and Bacteroides plebeius DSM 17135 . The cholesterol stones group had higher Desulfovibrionaceae and Bacteroides uniformis than the other two groups, while the pigment stone group had more abundant Escherichia-Shigella . In the analysis of metabolites, only n-butyric acid had a significantly higher concentration in the controls than in the gallstone group ( p < 0.01). The level of 3α-hydroxy-12 ketolithocholic acid, deoxycholic acid, and cholic acid showed no intergroup differences but was correlated to the serum cholesterol level and bacterial richness and evenness. CONCLUSION: Our study revealed the key taxa that can discriminate between individuals with or without gallstones. We also identified metabolites that are possibly associated with metabolic parameter and bacterial diversity. However, the correlation of the metabolites to certain clusters of bacteria should be analyzed in a larger cohort.

Mitochondrial dysfunction decreases cisplatin sensitivity in gastric cancer cells through upregulation of integrated stress response and mitokine GDF15.

Gastric neoplasm is a high-mortality cancer worldwide. Chemoresistance is the obstacle against gastric cancer treatment. Mitochondrial dysfunction has been observed to promote malignant progression. However, the underlying mechanism is still unclear. The mitokine growth differentiation factor 15 (GDF15) is a significant biomarker for mitochondrial disorder and is activated by the integrated stress response (ISR) pathway. The serum level of GDF15 was found to be correlated with the poor prognosis of gastric cancer patients. In this study, we found that high GDF15 protein expression might increase disease recurrence in adjuvant chemotherapy-treated gastric cancer patients. Moreover, treatment with mitochondrial inhibitors, especially oligomycin (a complex V inhibitor) and salubrinal (an ISR activator), respectively, was found to upregulate GDF15 and enhance cisplatin insensitivity of human gastric cancer cells. Mechanistically, it was found that the activating transcription factor 4-C/EBP homologous protein pathway has a crucial function in the heightened manifestation of GDF15. In addition, reactive oxygen species-activated general control nonderepressible 2 mediates the oligomycin-induced ISR, and upregulates GDF15. The GDF15-glial cell-derived neurotrophic factor family receptor a-like-ISR-cystine/glutamate transporter-enhanced glutathione production was found to be involved in cisplatin resistance. These results suggest that mitochondrial dysfunction might enhance cisplatin insensitivity through GDF15 upregulation, and targeting mitokine GDF15-ISR regulation might be a strategy against cisplatin resistance of gastric cancer.

Advanced gastric cancer patients with lymphoid stroma have better survival than those without.

BACKGROUND: Lymphoid stroma is a specific pathologic appearance in gastric cancer. This study aims to compare the clinicopathological characteristics of gastric cancer patients with and without lymphoid stroma. METHODS: From January 1988 to February 2009, 222 out of 1,959 patients with lymphoid stroma of gastric cancer received gastrectomy at the Department of Surgery, Taipei Veterans General Hospital. Clinicopathological characteristics and survival rates were analyzed and compared among the gastric cancer patients with and without lymphoid stroma. For patients with lymphoid stroma, CD20 expression of B lymphocytes and CD3 expression of T lymphocytes were examined using immunohistochemical stains. RESULTS: Advanced gastric cancer patients with lymphoid stroma had better 5-year survival status than those without lymphoid stroma (44.5% vs. 20.5%, P < 0.001). Univariate and multivariate analyses showed that male gender (P = 0.034), tumor invasion depth (P = 0.001), pathological staging (P = 0.006), and Ming's histological classification (P = 0.041) were significantly correlated with patients with lymphoid stroma. B lymphocytes appeared more in Borrmann type III and IV, diffuse Lauren's histological type, and lymph nodes metastases. CONCLUSION: Advanced gastric cancer patients with lymphoid stroma had better prognosis than those without lymphoid stroma. B lymphocytes appeared more in aggressive gastric cancer tissues with lymphoid stroma.

Aberrant expression of miR-196a in gastric cancers and correlation with recurrence.

MicroRNAs (miRNAs) are short noncoding RNAs (~22 nt) that play important roles in the pathogenesis of human diseases by negatively regulating gene expression. Here, we examined the relationship between miR-196a and gastric cancer.By the analysis of 72 gastric cancer samples, we found that the expression level of miR-196a microRNA significantly increased in primary gastric cancer tissues versus adjacent normal tissues. In addition, extracellular miR-196a detected in conditioned medium was strongly correlated with its cellular expression status and increased circulating miR-196a in patient serum was associated with gastric cancer disease status and relapse. Furthermore, ectopic expression of miR-196a microRNA promoted the epithelial-mesenchymal transition and migration/invasion capabilities of transfected cells, suggesting its oncogenic potential in gastric cancer progression. Altogether, our data demonstrate that miR-196a exerts an oncogenic role in gastric cancer and miR-196a may be a novel biomarker for detecting gastric cancer and for monitoring disease recurrence.

Early cholecystectomy following percutaneous transhepatic gallbladder drainage is effective for moderate to severe acute cholecystitis in the octogenarians.

BACKGROUND: Acute cholecystitis (AC) is a life-threatening infectious/inflammatory disease in older patients. This study aimed to investigate the safety and optimal timing of surgery in patients aged ≥ 80 years with moderate to severe AC who received percutaneous transhepatic gallbladder drainage (PTGBD). METHODS: From January 2008 to February 2021, 152 patients were retrospectively enrolled. Clinical outcomes were compared among patients who received laparoscopic cholecystectomy (LC), open cholecystectomy (OC), and conversion surgery, and between those who received early (< 6 weeks after PTGBD) and delayed cholecystectomy (≥ 6 weeks after PTGBD). Logistic regression analysis was used to identify risk factors for recurrent AC, further biliary events, conversion, and perioperative complications. RESULTS: Sixty-seven patients underwent LC, 62 underwent OC, and 23 underwent conversion surgery. Operation-related complications and mortality rates did not differ among the types of surgery; however, LC group had shorter operative time than the other groups. Eighty-two patients underwent early cholecystectomy, while 70 underwent delayed cholecystectomy. There were no differences in operative time, operation-related complications, and mortality rates between the groups. However, higher rates of recurrent AC and biliary events were observed in the delayed cholecystectomy group (52.9% vs. 4.9% and 57.1% vs. 8.5%, p < 0.001). On multivariate analysis, delayed cholecystectomy was a significant risk factor for recurrent AC (odds ratio [OR] = 19.42, p < 0.001) and further biliary events (OR = 15.95, p < 0.001). CONCLUSIONS: Early cholecystectomy is recommended for patients aged ≥ 80 years with moderate to severe AC following PTGBD.

Comparative analyses of complete chloroplast genomes reveal interspecific difference and intraspecific variation of Tripterygium genus.

The genus Tripterygium was of great medicinal value and attracted much attention on the taxonomic study using morphological and molecular methods. In this study, we assembled 12 chloroplast genomes of Tripterygium to reveal interspecific difference and intraspecific variation. The sequence length (156,692-157,061 bp) and structure of Tripterygium were conserved. Comparative analyses presented abundant variable regions for further study. Meanwhile, we determined the ndhB gene under positive selection through adaptive evolution analysis. And the phylogenetic analyses based on 15 chloroplast genomes supported the monophyly of Tripterygium hypoglaucum and the potential sister relationship between Tripterygium wilfordii and Tripterygium regelii. Molecular dating analysis indicated that the divergence time within Tripterygium was approximately 5.99 Ma (95% HPD = 3.11-8.68 Ma). The results in our study provided new insights into the taxonomy, evolution process, and phylogenetic construction of Tripterygium using complete plastid genomes.

Comparison of the mutation patterns between tumor tissue and cell-free DNA in stage IV gastric cancer.

Compared to stage I-III gastric cancer (GC), the level of cell-free DNA (cfDNA) was significantly higher in stage IV GC. The mutation patterns of different metastatic patterns between cfDNA and tumor DNA in stage IV GC have not yet been reported. We used next-generation sequencing (NGS) to analyze cfDNA and tumor DNA in 56 stage IV GC patients. Tumor DNA and cfDNA were analyzed using a 29-gene NGS panel. In tumor samples, the most commonly mutated gene was TP53 (64%), followed by ARID1A (62%), KMT2C (60%) and KMT2D (58%). In cfDNA samples, the most commonly mutated genes were FAT4 (19%) and MACF1 (19%), followed by KMT2D (18%), ARID1A (14%) and LRP1B (14%). The concordance of mutation patterns in these 29 genes was 42.0% between cfDNA and tumor DNA. A specificity of 100% was found when using the mutation status of cfDNA to predict mutations in tumor samples. The sensitivity of the mutation status of cfDNA to predict mutation in tumor samples was highest in FAT4 (88.9%), followed by MACF1 (80%), CDH1 (75%) and PLB1 (75%). For cfDNA with PLB1 mutations, patients were more likely to develop distant lymphatic metastasis than peritoneal metastasis. Patients with multiple-site metastases had significantly more mutated spots than patients with single-site metastasis. Due to the high sensitivity and specificity of some genes in the prediction of mutation in tumor samples, monitoring the mutation pattern of cfDNA may be useful in the stage IV GC treatment.

The clinicopathological and genetic differences among gastric cancer patients with no recurrence, early recurrence, and late recurrence after curative surgery.

BACKGROUND: To date, few reports have investigated the genetic alterations and clinicopathological features among gastric cancer (GC) patients with no tumor recurrence, early recurrence, and late recurrence following curative surgery. METHODS: A total of 473 GC patients undergoing curative surgery were included. The clinicopathological characteristics, patient prognosis, recurrence patterns, and genetic alterations were compared between GC patients with early recurrence and late recurrence. RESULTS: Among the 473 GC patients, 119 had early recurrence (<2 years) and 45 had late recurrence (≥2 years). Patients with early recurrence had tumor size larger than 5 cm, fewer superficial-type tumors, more lymphovascular invasion, more advanced pathological T and N categories and Tumor, Node, Metastasis (TNM) stages, and worse 5-year overall survival than patients with late recurrence and no recurrence. For intestinal-type GC, patients with no tumor recurrence had more Helicobacter pylori infection than patients with early recurrence and late recurrence; for diffuse-type GC patients, the frequency of PIK3CA amplification was the highest in early recurrence, followed by late recurrence and no recurrence. GC patients with single-site recurrence had more ARID1A mutations than those with multiple-site recurrence. Multivariate analysis demonstrated that age, tumor recurrence, and pathological N categories were independent prognostic factors. CONCLUSION: PIK3CA amplifications were more common in diffuse-type GC with early recurrence, whereas ARID1A mutations were more common in patients with single-site recurrence. Targeted therapy and immunotherapy might be helpful for these patients.

Immunoprofile of adenosquamous carcinoma in gastric cancer.

BACKGROUND: Gastric adenosquamous carcinoma (GASC) is a rare subtype of gastric cancer. Research on GASC treatment is limited, and its outcome is usually poor. We investigated the clinical features, immunoprofile of GASC, and determined the optimal treatment modality for these patients. METHODS: Patients with GASC from Taipei Veterans General Hospital were retrospectively reviewed. Clinical features and treatment outcomes were evaluated. Adequate samples were examined for surrogate biomarkers for immunotherapy by IHC staining. RESULTS: Total 14 (0.35%) GASC patients were found among 4034 gastric cancer patients. The median tumor size was 6.8 cm in 10 patients with stage III GASC, and all these patients underwent radical gastrectomy followed by adjuvant therapy. The median progression-free survival (PFS) and overall survival (OS) were 6.0 and 11.5 months, respectively. Two patients with stage IV GASC received frontline immunotherapy. Their median PFS and OS were 9.0 and 12.5 months. In immunoprofiling, 25.0% (n = 3), 75.0% (n = 9), and 33.3% (n = 4) of the samples had deficient mismatch repair (dMMR) protein, combined positive score (CPS) of ≥1, and CPS of ≥10, respectively. The univariate analysis revealed that programmed death-ligand 1 ≥5% (HR: 0.12; 95% CI: 0.01-0.97; p = 0.047) was significant associated with superior OS. One stage IV patient with CPS ≥10 and dMMR proteins received nivolumab monotherapy as frontline treatment that resulted 14-month PFS. CONCLUSION: Patients with GASC are more likely to yield positive results for CPS and dMMR. Biomarkers should be examined, and immunotherapy can be considered as frontline systemic treatment.

Elevated PD-L1 Expression and Microsatellite Instability in Elderly Patients With Gastric Cancer.

Immunotherapy in combination with chemotherapy is the current treatment of choice for frontline programmed cell death ligand 1 (PD-L1)-positive gastric cancer. However, the best treatment strategy remains an unmet medical need for elderly or fragile patients with gastric cancer. Previous studies have revealed that PD-L1 expression, Epstein-Barr virus association, and microsatellite instability-high (MSI-H) are the potential predictive biomarkers for immunotherapy use in gastric cancer. In this study, we showed that PD-L1 expression, tumor mutation burden, and the proportion of MSI-H were significantly elevated in elderly patients with gastric cancer who were older than 70 years compared with patients younger than 70 years from analysis of The Cancer Genome Atlas gastric adenocarcinoma cohort [≥70/<70: MSI-H: 26.8%/15.0%, P =0.003; tumor mutation burden: 6.7/5.1 Mut/Mb, P =0.0004; PD-L1 mRNA: 5.6/3.9 counts per million mapped reads, P =0.005]. In our real-world study, 416 gastric cancer patients were analyzed and showed similar results (≥70/<70: MSI-H: 12.5%/6.6%, P =0.041; combined positive score ≥1: 38.1%/21.5%, P <0.001). We also evaluated 16 elderly patients with gastric cancer treated with immunotherapy and revealed an objective response of 43.8%, a median overall survival of 14.8 months, and a median progression-free survival of 7.0 months. Our research showed that a durable clinical response could be expected when treating elderly patients with gastric cancer with immunotherapy, and this approach is worth further study.