[68Ga]Ga-FAPI-04 PET/MR imaging strategy in management of Krukenberg tumors (KTs) from gastric signet-ring-cell carcinoma: to overcome limitation of [68Ga]Ga-FAPI-04 PET imaging in KTs.

PURPOSE: To compare performance of whole-body [68Ga]Ga-FAPI-04 and [18F]FDG PET imaging in the detection of Krukenberg tumors (KTs), primary site and extra-ovarian metastases of gastric signet-ring-cell carcinoma (GSRCC), and evaluate the value of [68Ga]Ga-FAPI-04 PET/MR imaging strategy and its potential impact on the management of KTs from GSRCC. METHODS: Twelve patients with twenty-three KTs from GSRCC, who underwent both [68Ga]Ga-FAPI-04 pelvic PET/MR and whole-body [68Ga]Ga-FAPI-04 and [18F]FDG PET imaging were retrospectively analyzed. [68Ga]Ga-FAPI-04 and [18F]FDG uptakes were compared by using Wilcoxon signed-rank test or paired t test. McNemar's test was used to compare lesion detectability between two modalities. Two-tailed P<0.05 was considered statistically significant. Immunohistochemistry staining was utilized to analyze the fibroblast activation protein (FAP) expression in KTs. RESULTS: A total of 12 patients with 23 KTs from GSRCC (8 synchronous and 4 metachronous) were evaluated. [68Ga]Ga-FAPI-04 was superior to [18F]FDG PET in detecting primary sites of GSRCC (100% [11/11] vs. 18.2% [2/11], p = 0.002), involved lymph nodes (90.9% [10/11] vs. 54.5% [6/11], p = 0.046) and peritoneal metastases (100% [12/12] vs. 41.7% [5/12], p = 0.008), with higher SUVmax and TBR (all p < 0.005). Both tracers had limited value in identifying KTs, with 100% false negative rate on [68Ga]Ga-FAPI-04 PET and a low detection rate of 8.7% on [18F]FDG PET. Fap immunohistochemistry showed negative or slight FAP expression in neoplastic signet ring cells and ovarian stroma. [68Ga]Ga-FAPI-04 PET/MR imaging strategy greatly improved the detection rate of Krukenberg tumors (87%, 20/23). After adding diffusion-weighted imaging (DWI), the detection rate was further improved (87.5% vs. 100%, p = 0.083). [68Ga]Ga-FAPI-04 PET/MR imaging strategy either upgraded TNM staging or changed treatment management in twelve patients. CONCLUSIONS: [68Ga]Ga-FAPI-04 PET outperformed [18F]FDG PET in detecting primary site and most extra-ovarian metastases of GSRCC, but both tracers had limited value in identifying Krukenberg tumors. Pelvis MRI should be applied to compensate the limitation of [68Ga]Ga-FAPI-04 PET imaging to identify Krukenberg tumours. The [68Ga]Ga-FAPI-04 PET/MR imaging strategy has the potential to impact treatment decisions for GSRCC patients with KTs.

A novel web-based dynamic prognostic nomogram for gastric signet ring cell carcinoma: a multicenter population-based study.

Background: Gastric signet ring cell carcinoma (GSRCC) is a rare and highly malignant disease with a poor prognosis. To assess the overall survival (OS) and cancer-specific survival (CSS) of patients with GSRCC, prognostic nomograms were developed and validated using common clinical factors. Methods: This retrospective cohort study included patients diagnosed with GSRCC between 2011 and 2018 from the National Cancer Center (n = 1453) and SEER databases (n = 2745). Prognostic nomograms were established by identifying independent prognostic factors using univariate and multivariate Cox regression analyses. The calibration curve and C-index were used to assess the predictions. The clinical usefulness of the survival prediction model was further evaluated using the DCA and ROC curves. The models were internally validated in the training cohort and externally validated in the validation cohort. Two web servers were created to make the nomogram easier to use. Results: Patients with GSRCC were divided into training (n = 2938) and validation (n = 1260) cohorts. The nomograms incorporated six predictors: age, race, tumor site, tumor size, N stage, T stage, and AJCC stage. Excellent agreement was observed between the internal and exterior calibration plots for the GSRCC survival estimates. The C-index and area under the ROC curve were roughly greater than 0.7. Both nomograms had adequate clinical efficacy, as demonstrated by the DCA plots. Furthermore, we developed a dynamic web application utilizing the constructed nomograms available at https://jiangyujuan.shinyapps.io/OS-nomogram/ and https://jiangyujuan.shinyapps.io/DynNomapp-DFS/. Conclusion: We developed web-based dynamic nomograms utilizing six independent prognostic variables that assist physicians in estimating the OS and CSS of patients with GSRCC.

A Rare Case of Primary Gastric Signet Ring Cell Carcinoma: a Review of Guidelines for the Management of Gastric Cancer.

Gastric carcinoma is the fifth most common and the third leading cause of cancer deaths worldwide. The incidence of diffuse-type gastric cancer, of which signet ring cell carcinoma is a subtype, is rising in the world. Due to non-specific gastritis-like symptoms, difficulty in assessing true tumor characteristics owing to its horizontal spread, and non-distinguishable endoscopic appearance from other gastric pathologies, the diagnosis of this subtype is challenging. We present a case of a 67-year-old woman with progressively worsening abdominal pain who came for an endoscopic ultrasound evaluation of an incidentally noted pancreatic cyst on a previous MRI. During endoscopy, a 1-cm gastric ulcer was noted along the lesser curvature of the gastric body. Biopsy confirmed a diagnosis of gastric signet ring cell carcinoma (SRCC) with CDX-2 and keratin positivity. The patient underwent total gastrectomy with Roux-en-Y reconstruction. Gross specimen revealed a diffuse SRCC invading the muscularis propria, along with lymphovascular and perineural invasion. In the context of our case, we discuss the morphological features of SRCC and the effectiveness of treatment options based on existing literature. Early accurate diagnosis and staging play an important role in determining treatment options as well as the clinical course of gastric SRCC.

Prognostic significance of serum tumor markers in various pathologic subtypes of gastric cancer.

PURPOSE: This study aimed to assess the utility of 6 serum tumor markers in prognosis between gastric adenocarcinoma and gastric signet ring cell carcinoma (SRCC). METHODS: A cohort of 3131 cases of gastric adenocarcinoma and 275 cases of gastric SRCC was assembled. The serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 125, alpha fetoprotein (AFP), carbohydrate antigen 242 (CA242), and carbohydrate antigen 724 (CA724) were measured in all cases. The study analyzed the association between the levels of these 6 tumor markers and the prognosis of gastric adenocarcinoma and SRCC. RESULTS: The study revealed that gastric SRCC exhibited lower concentrations of CEA (P < .001) and CA19-9 (P = .002), along with reduced positive rates of CEA (P = .041), CA19-9 (P = .003), AFP (P < .001), and CA242 (P = .006), while displaying higher positive rates of CA724 (P = .024) than gastric adenocarcinoma. Nevertheless, the receiver operating characteristic curve demonstrated that serum tumor markers did not hold clinical significance in differentiating between gastric adenocarcinoma and SRCC. Survival analysis substantiated that the combined criteria of serum tumor markers stood as an independent risk factor for both gastric adenocarcinoma and SRCC. Notably, the nomogram indicated that serum tumor markers exerted a more substantial influence on the prognosis of gastric adenocarcinoma than on gastric SRCC. CONCLUSION: The study concluded that the combined criteria of serum tumor markers emerge as independent risk factors for both subtypes of gastric cancer. Furthermore, this combined approach exhibited enhanced efficacy in prognosticating the outcome of gastric adenocarcinoma compared with gastric SRCC.

A Prognostic Model for Survival in Patients with Gastric Signet Ring Cell Carcinoma.

INTRODUCTION: The objective of our study was to develop a nomogram to predict overall survival (OS) and cancer-specific survival (CSS) in patients with gastric signet ring cell carcinoma (GSRCC). METHODS: A total of 3,408 GSRCC patients between 1975 and 2017 were screened from the Surveillance, Epidemiology, and End Results (SEER) database and randomly divided into training and validation cohorts. Univariate and multivariate Cox analyses were conducted to identify independent prognostic factors for the construction of a nomogram. The performance of the model was then assessed by the concordance index (C-index), calibration plot, and area under the receiver operating characteristic curve (AUC). Then, the novel nomogram was further assessed by 64 GSRCC patients from our hospital as the external cohort. RESULTS: We identified age, tumor lymph node metastasis (TNM) staging system, surgery, and chemotherapy as significant independent elements of prognosis. On this basis, a nomogram was constructed, with a C-index of OS in the training and validation cohorts of 0.763 (95% CI: 0.751-0.774) and 0.766 (95% CI: 0.748-0.784) and a C-index of CSS of 0.765 (95% CI: 0.753-0.777) and 0.773 (95% CI: 0.755-0.791), respectively. The AUCs of the nomogram for predicting 2- and 5-year OS were 0.848 and 0.885, respectively, and those for predicting CSS were 0.854 and 0.899, respectively, demonstrating the excellent predictive value of the constructed nomogram compared to the traditional AJCC staging system. Similar results were also observed in both the internal and external validation sets. CONCLUSION: The nomogram provided an accurate tool to predict OS and CSS in patients with GSRCC, which can assist clinicians in making predictions about individual patient survival.

Survival impact of gastrectomy and chemotherapy on gastric signet ring-cell carcinoma with different metastatic lesions: A population-based study.

BACKGROUND: A comprehensive understanding of gastric signet ring cell carcinoma (SRCC) is limited. The aim of our study was to analyze metastatic patterns of gastric SRCC and evaluate impacts of gastrectomy and chemotherapy for metastatic gastric SRCC. METHODS: We obtained data of gastric cancer patients between 2010 and 2017 in the Surveillance, Epidemiology, and End Results database. Chi-square tests were used to compare data significance. Kaplan-Meier, Cox proportional hazards regression and Fine-Gray competing risk analysis were used to analyze the difference in the overall survival (OS) and cancer-specific survival (CSS). Propensity-score matching was used to adjust numerical difference. RESULTS: Among 36,459 eligible gastric cancer patients, 6264 (17.2 %) were SRCC patients. Bone metastasis was more common in SRCC patients than in non-SRCC patients. The multivariate analysis showed that chemotherapy (HR = 0.30, 95 %CI = 0.27-0.33, p < 0.01) and gastrectomy (HR = 0.51, 95 %CI = 0.45-0.59, p < 0.01) were protective prognostic factors in certain stage Ⅳ SRCC patients. For the effect of gastrectomy, survival benefits could be found in patients with liver metastasis. The gastrectomy was not associated with improved OS in patients with lung or multiple metastases. In subgroup analysis, SRCC patients with metastasis who received gastrectomy and chemotherapy (HR = 0.17, p < 0.01; HR = 0.03, p < 0.01) had a better OS and CSS than those who had chemotherapy only (HR = 0.30, p < 0.01; HR = 0.18, p < 0.01). CONCLUSION: Our study analyzed the unique metastatic patterns of gastric SRCC and recommended chemotherapy as the first choice in metastatic SRCC. For patients with liver metastasis, gastrectomy plus chemotherapy can be considered.

Immune checkpoint inhibitor-related chronic pneumonitis: a case report and literature review.

Immune checkpoint inhibitor (ICI)-related chronic pneumonitis is rare. Limited information is available on the characteristics of this condition. Herein, we present the case of a 54-year-old man with recurrent severe ICI-related pneumonitis. The patient developed fever and dyspnea during both episodes of pneumonitis. He had been previously diagnosed with gastric signet ring cell carcinoma and was undergoing treatment with an anti-PD-1 combination chemotherapy regimen. We reviewed previous case reports of ICI-related pneumonitis according to the primary cancer, time of onset in relation to ICI therapy and chest imaging findings. ICI-related pneumonitis can progress to chronic pneumonitis. Repeated computed tomography imaging showing lung changes in the same location may help to make the diagnosis.

Immune checkpoint inhibitors (ICIs) are a type of medicine that helps fight stomach cancer but sometimes they can cause problems with the lungs. This case report is about a man who had two bad lung incidents after taking ICI medicine. He had trouble breathing and fever both times. Other people have had similar problems with their lungs after being given ICI treatment. We compared chest pictures of the patient receiving ICI treatment over time and saw changes in the same spot meaning there might be a long-term problem with the lungs. We need to do more research to figure out how to treat this problem better.

The prognostic value of FAR and a novel FAR-CA125 score in resectable gastric signet ring cell carcinoma patients.

BACKGROUND: The fibrinogen to albumin ratio (FAR) is increasingly regarded as a potential biomarker for predicting prognosis in variety of malignant tumors, but not in gastric signet ring cell carcinoma (GSRC). This study seeks to examine the prognostic value of the FAR and explore a novel FAR-CA125 score (FCS) in resectable GSRC patients. METHODS: A retrospective cohort was conducted including 330 GSRC patients who underwent curative resection. Kaplan-Meier (K-M) and Cox regression were used to analysis the prognostic value of FAR and FCS. And a predictive nomogram model was developed. RESULTS: The optimal cut-off values for CA125 and FAR were 9.88 and 0.0697, respectively, according to the receiver operating characteristic curve (ROC). Th area under the ROC curve of FCS is higher than CA125 and FAR. 330 patients were grouped into three groups according to the FCS. High FCS was related to males, anemia, tumor size, TNM stage, lymph node metastasis, tumor invasion depth, SII, and pathological subtypes. K-M analysis showed that high FCS and FAR were associated with poor survival. In the multivariate analysis, FCS, TNM stage, and SII were independent prognostic factors for poor OS in resectable GSRC patients. And the predictive accuracy of clinical nomogram contained FCS was better than TNM stage. CONCLUSION: This study indicated that the FCS is a prognostic, and effective biomarker for patients with surgically resectable GSRC. Such developed FCS-based nomogram could be effective tools to assist the clinicians to determine the treatment strategy.

Survival Outcome of Gastric Signet Ring Cell Carcinoma Based on the Optimal Number of Examined Lymph Nodes: A Nomogram- and Machine-Learning-Based Approach.

The optimal number of examined lymph nodes (ELNs) for gastric signet ring cell carcinoma recommended by National Comprehensive Cancer Network guidelines remains unclear. This study aimed to determine the optimal number of ELNs and investigate its prognostic significance. In this study, we included 1723 patients diagnosed with gastric signet ring cell carcinoma in the Surveillance, Epidemiology, and End Results database. X-tile software was used to calculate the cutoff value of ELNs, and the optimal number of ELNs was found to be 32 for adequate nodal staging. In addition, we performed propensity score matching (PSM) analysis to compare the 1-, 3-, and 5-year survival rates; 1-, 3-, and 5-year survival rates for total examined lymph nodes (ELNs < 32 vs. ELNs ≥ 32) were 71.7% vs. 80.1% (p = 0.008), 41.8% vs. 51.2% (p = 0.009), and 27% vs. 30.2% (p = 0.032), respectively. Furthermore, a predictive model based on 32 ELNs was developed and displayed as a nomogram. The model showed good predictive ability performance, and machine learning validated the importance of the optimal number of ELNs in predicting prognosis.

Comprehensive Analysis of Clinicopathological and Molecular Features to Predict Anti-PD-1-Based Therapy Efficacy in Patients with Advanced Gastric Signet Ring Cell Carcinoma.

BACKGROUND: Signet ring cell carcinoma (SRCC) is a specific type of gastric cancer. The clinicopathological and molecular characteristics that can be used to predict the response to anti-PD-1 therapy for these patients are still not clear. METHODS: Patients with advanced SRCC who received first-line anti-PD-1-based treatment were enrolled in this study. The clinicopathological characteristics of these patients were obtained from their medical records. The molecular features of these patients were analyzed by means of a next-generation-sequencing-based panel. The predictive significance of clinicopathological and molecular features for efficacy was analyzed. RESULTS: A total of 71 patients with measurable lesions were included in this study, among which 46 patients had enough tissues for next-generation sequencing. The overall objective response rate (ORR) was 46.4%. ORR was significantly higher in mismatch repair (MMR)-deficient (dMMR) patients than in MMR-proficient (pMMR) patients, in patients with lymph node metastasis only than those with other metastasis sites, and in patients with an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 than with a PS of 1 or 2. The progression-free survival was significantly longer in patients with dMMR, lymph node metastasis only, PD-L1 combined positive score (CPS) ≥ 5, and CDH1 wild type. CONCLUSIONS: Several clinicopathological and molecular features are associated with anti-PD-1 treatment efficacy in SRCC, which might be used to identify patients who can benefit most from these therapies.

Pathological Nodal Staging Score for Gastric Signet Ring Cell Carcinoma: A Clinical Tool of Adequate Nodal Staging.

Background: Gastric signet ring cell carcinoma (GSRCC) is a subset of gastric cancer with distinct histological and inconsistent prognosis outcome. Currently, the association between the adequate regional lymph node and proper nodal staging in GSRCC is rarely noticed. Materials and methods: Clinical data of GSRCC were retrieved from the Surveillance, Epidemiology, and End Results database. Beta-binomial distribution model was employed for the estimation of the probability of missing nodal disease, followed by the development of a nodal staging score (NSS). Results: A total of 561 GSRCC patients were included in this study, with 193 in lymph node-negative and 368 in lymph node-positive diagnoses. As the number of examined lymph nodes increased, the probability of missing nodal disease decreased rapidly, with T stage-specific curves. The probability of missing nodal disease in T4 was lower than that in T1. NSS calculation indicated that T1 stage patients commonly had NSS > 0.8. However, with the NSS of T2−T4 to reach 0.8, the number of examined lymph node was required to be larger than 12 in T2, 17 in T3 and 27 in T4. NSS ≥ 0.75 (quantile 75%) subgroup in T2−T4 subgroups tended to have better outcome; however, without significant prognostic value. Conclusions: NSS is served as a reliable and feasible tool in adequate nodal staging of GSRCC with statistical basis and provides further evidence for clinical decision making.

Clinicopathological characteristics and prognosis of gastric signet ring cell carcinoma.

BACKGROUND: The clinicopathological features and prognosis of gastric signet ring cell carcinoma (GSRC) remain controversial, particularly with regard to sensitivity to postoperative adjuvant therapy. AIM: To compare the pathological features of GSRC with those of gastric adenocarcinoma of different degrees of differentiation and the differences in survival prognosis between the different disease processes. METHODS: By screening gastric cancer patients from 2010 to 2015 in the database of Surveillance, Epidemiology and End Results, and collecting the clinicopathological and prognostic data of gastric cancer patients who underwent surgery from January 2014 to December 2016 in the Second Affiliated Hospital of Nanchang University, we analyzed the general pathological characteristics of GSRC by the chi-square test. Univariate and multivariate analyses were conducted to compare the factors affecting the survival and prognosis of early and advanced gastric adenocarcinoma. The Kaplan-Meier curves were plotted to reveal the survival difference between early and advanced GSRC and different differentiated types of gastric adenocarcinoma. The prognosis model of advanced GSRC was established with R software, and the area under curve (AUC) and C-index were used to assess the accuracy of the model. RESULTS: Analysis of pathological features revealed that signet ring-cell carcinoma (SRC) was more frequently seen in younger (< 60 years), female, and White patients compared to non-SRC patients. SRC was less commonly associated with early gastric cancer (EGC) (23.60% vs 39.10%), lower N0 (38.61% vs 61.03%), and larger tumour sizes > 5 cm (31.15% vs 27.10%) compared to the differentiated type, while the opposite was true compared to the undifferentiated type. Survival prognostic analysis found no significant difference in the prognosis of SRC patients among EGC patients. In contrast, among advanced gastric cancer (AGC) patients, the prognosis of SRC patients was correlated with age, race, tumour size, AJCC stage, T-stage, and postoperative adjuvant therapy. The predictive model showed that the 3-year AUC was 0.787, 5-year AUC was 0.806, and C-index was 0.766. Compared to non-SRC patients, patients with SRC had a better prognosis in EGC [hazard ratio (HR): 0.626, 95% confidence interval (CI): 0.427-0.919, P < 0.05] and a worse prognosis in AGC (HR: 1.139, 95%CI: 1.030-1.258, P < 0.05). When non-SRC was divided into differentiated and undifferentiated types for comparison, it was found that in EGC, SRC had a better prognosis than differentiated and undifferentiated types, while there was no significant difference between differentiated and undifferentiated types. In AGC, there was no significant difference in prognosis between SRC and undifferentiated types, both of which were worse than differentiated types. A prognostic analysis of postoperative adjuvant therapy for SRC in patients with AGC revealed that adjuvant postoperative radiotherapy or chemotherapy significantly improved patient survival (34.6% and 36.2% vs 18.6%, P < 0.05). CONCLUSION: The prognosis of SRC is better than that of undifferentiated type, especially in EGC, and its prognosis is even better than that of differentiated type. SRC patients can benefit from early detection, surgical resection, and aggressive adjuvant therapy.

Facial Cutaneous Metastases of Gastric Signet-ring Cell Carcinoma: Resection and Reconstruction as a Palliative Surgical Treatment Option.

BACKGROUND: Cutaneous metastases of gastric signet-ring cell gastric carcinoma are very rare. Our following case report highlights the need for careful clinical examination and skin biopsy of newly developing scar-like or erythematous skin lesions in patients with a known history of malignant disease in order to prevent diagnostic and therapeutic delay. CASE REPORT: A 68-year-old male patient presented with two slightly painful, erythematous, facial skin lesions (chin and forehead) 2 years after gastrectomy for a signet-ring cell gastric carcinoma. The patient complained of intermittent neuropathic pain in the area of the mental nerve. A biopsy of both skin lesions demonstrated metastasis of signet-ring cell gastric carcinoma. Following discussion within the multidisciplinary tumor board, palliative surgical excision was recommended for this patient. Both skin lesions were resected and the large defect in the chin region was primarily closed by a cervical skin transposition flap. CONCLUSION: The presented case report of a patient with a known history of malignancy illustrates that newly developing erythematous skin lesions may be suspicious for cutaneous metastases. Palliative surgical interventions may play a role even in an advanced disease stage.

Alternative medicine: therapeutic effects on gastric original signet ring carcinoma via ascorbate and combination with sodium alpha lipoate.

BACKGROUND: Gastric signet ring cell carcinoma (SRCC) is an aggressive gastric adenocarcinoma with a poor prognosis when diagnosed at an advanced stage. As alternative medicine, two natural supplements (ascorbate (AA) and sodium alpha lipoate (LA)) have been shown to inhibit various cancers with mild side effects. METHODS: These two natural supplements and a series of combinations (AA&LA, AA+LA and LA + AA) were incubated with non-SRCC cells (GPM-1), patient-derived gastric origin SRCC (GPM-2), gastric-origin SRCCs (HSC-39 and KATO-3), human pancreatic (MIA PaCa-2) and ovarian (SKOV-3) cells for evaluating their therapeutic effects. Moreover, these treatments were applied in 3D-cultured organoids to reveal the feasibility of these approaches for in vivo study. RESULTS: Analyzing their antioxidant capabilities and dose-response curves, we observed that all four gastric cell lines, including three patient-derived cell lines were sensitive to ascorbate (~ 10 mM). The influence of ascorbate incubation time was studied, with a 16-h incubation found to be optimal for in vitro studies. Moreover, a simultaneous combination of AA and LA (AA&LA) did not significantly inhibit cell proliferation, while prior LA treatment increased the growth inhibition of AA therapy (LA + AA). Anti-cancer efficacy of AA was further confirmed in 3D-cultured SRCC (KATO-3) organoids. CONCLUSIONS: This study highlights the potential of AA and LA + AA in treating gastric origin SRCC, and demonstrates the influence of order in which the drugs are administered.

A potential novel biomarker in predicting lymph node metastasis of gastric signet ring cell carcinoma: A derived monocyte to lymphocyte ratio.

BACKGROUND: This study is designed to evaluate the predictive value of derived monocyte to lymphocyte ratio (dMLR), neutrophil to lymphocyte ratio (NLR) and eosinophil to lymphocyte ratio (ELR) for lymph node metastasis (LNM) in gastric signet ring cell carcinoma (SRCC) patients. METHODS: We carried out a retrospective analysis for 203 eligible patients who underwent radical gastrectomy between January 2011 and September 2020. RESULTS: The diagnostic sensitivity and specificity for dMLR were 60.3% and 72.2%, respectively; while for NLR and ELR were 64.1% and 66.6%, and 91.6% and 23.6%, respectively. The dMLR and NLR were identified as independent predictors of LNM, but ELR was not. A nomogram was developed incorporating dMLR and clinical characteristics with AUC of 0.868, and the outcome of DCA supported good clinical benefit. CONCLUSIONS: dMLR is a promising novel preoperative biomarker to predict LNM of gastric SRCC.

KRAS gene status in gastric signet-ring cell carcinoma patients and acts as biomarker of MEK inhibitor.

BACKGROUND: Signet-ring cell carcinoma (SRCC) is a specific subtype of stomach cancer with unique epidemiology. Here, we sought to explore the role of KRAS in SRCC. METHODS: KRAS status was studied both in The Cancer Genome Atlas (TCGA) and internal cohorts. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were performed in formalin-fixed and paraffin-embedded (FFPE) samples. We explored patients' survival and clinicopathological characteristics in terms of KRAS mutation and expression. We also explored KRAS status and drug response curve of MEK/mTOR inhibitors in SRCC cell lines. RESULTS: Patients with KRAS mutations and copy number variation (CNV) showed higher mRNA level compared to non-mutant cases (P=0.003 and P<0.001). In internal cohort, 15 samples harbored KRAS mutations. Survival analysis showed that these patients had significantly lower overall survival (OS) (P=0.048). We further analyzed 75 patients with sufficient FFPE samples. Eight patients showed KRAS mutations and one patient showed KRAS amplification. The median OS was 12.5 months for patients with KRAS mutation, and 19.5 months for patients without KRAS mutation (P=0.005). Positive expression of KRAS as shown by IHC was detected in majority of SRCC samples, which was higher than our intestinal cohort (28% vs. 12.6%, P=0.033). We further explored the correlation between KRAS status and drug sensitivity in 4 SRCC cell lines. SNU601 and SNU668, which harbored KRAS mutation, were hypersensitive to MEK and mTOR inhibitors than KRAS wide type cell lines KATO-III and NUGC-4. CONCLUSIONS: Our findings demonstrate that KRAS gene plays an important role in SRCC and reveals therapeutic potential of targeting tumors by inhibiting MEK and mTOR pathways.

A Prognostic Model for Patients With Gastric Signet Ring Cell Carcinoma.

BACKGROUND: The aim of our study was to develop a nomogram model to predict overall survival (OS) and cancer-specific survival (CSS) in patients with gastric signet ring cell carcinoma (GSRC). METHODS: GSRC patients from 2004 to 2015 were collected from the Surveillance, Epidemiology, and End Results (SEER) database and randomly assigned to the training and validation sets. Multivariate Cox regression analyses screened for OS and CSS independent risk factors and nomograms were constructed. RESULTS: A total of 7,149 eligible GSRC patients were identified, including 4,766 in the training set and 2,383 in the validation set. Multivariate Cox regression analysis showed that gender, marital status, race, AJCC stage, TNM stage, surgery and chemotherapy were independent risk factors for both OS and CSS. Based on the results of the multivariate Cox regression analysis, prognostic nomograms were constructed for OS and CSS. In the training set, the C-index was 0.754 (95% CI = 0.746-0.762) for the OS nomogram and 0.762 (95% CI: 0.753-0.771) for the CSS nomogram. In the internal validation, the C-index for the OS nomogram was 0.758 (95% CI: 0.746-0.770), while the C-index for the CSS nomogram was 0.762 (95% CI: 0.749-0.775). Compared with TNM stage and SEER stage, the nomogram had better predictive ability. In addition, the calibration curves also showed good consistency between the predicted and actual 3-year and 5-year OS and CSS. CONCLUSION: The nomogram can effectively predict OS and CSS in patients with GSRC, which may help clinicians to personalize prognostic assessments and clinical decisions.

Development and Validation of a Prognostic Nomogram for Gastric Signet Ring Cell Carcinoma: A Multicenter Population-Based Study.

BACKGROUND: Gastric signet ring cell carcinoma (GSRCC) is a rare disease associated with poor prognosis. A prognostic nomogram was developed and validated in this study to assess GSRCC patients' overall survival (OS). METHODS: Patients diagnosed with GSRCC from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2016) and the First Hospital of China Medical University (CMU1h) were enrolled in this retrospective cohort study. Univariate and multivariate COX analysis was used to determine independent prognostic factors to construct the prognostic nomogram. Predictions were evaluated by the C-index and calibration curve. In addition, the receiver operating characteristic (ROC) curve, decision curve analysis (DCA), and Kaplan-Meier analysis were employed to assess the clinical utility of the survival prediction model. RESULTS: Patients were classified into two cohorts. We randomly divided patients in the SEER database and CMU1h cohort into a training group (n=3068, 80%) and a validation group (n=764, 20%). Age, race, T stage, N stage, M stage, therapy, and tumor size were significantly associated with the prognosis of GSRCC patients. On this basis, a nomogram was constructed, with a C-index in the training and the validation cohorts at 0.772 (95% CI: 0.762-0.782) and 0.774 (95% CI: 0.752-0.796), respectively. The accuracy of the generated nomogram was verified through calibration plots. Similarly, compared with the traditional AJCC staging system, the results of the area under curve (AUC) calculated by ROC, DCA, and Kaplan-Meier curves, demonstrated a good predictive value of the constructed nomogram, compared to the traditional AJCC staging system. CONCLUSION: In the present study, seven independent prognostic factors of GSRCC were screened out. The established nomogram models based on seven variables provided a visualization of each prognostic factor's risk and assisted clinicians in predicting the 1-, 3-, and 5-year OS of GSRCC.

Exceptional Symbiosis Between Tumors: A Case of Gastric Signet Ring Cell Metastasis in Chromophobe Carcinoma of the Kidney.

Tumor-to-tumor metastasis is the presence of a metastatic deposit within a second malignant primary, and its identification could be challenging, particularly when the latter malignancy has not yet been discovered. Renal cell carcinoma is one of the known recipients. Here we present a 52 years old woman who presented with a small nodule in the left kidney, which had a biphasic cell proliferation, chromophobe type, and signet-ring cell type for which we suggested to investigate the presence of a second tumor of gastrointestinal origin. We present this case for the rarity of its presentation, for the peculiar histological symbiosis we found between the two tumor entities, and for the challenging diagnosis due to the presence of an occult aggressive primary tumor.