The Clinicopathological Characteristics And Genetic Alterations of Signet-ring Cell Carcinoma in Gastric Cancer

Immunosuppressive tumor microenvironment in gastric signet-ring cell carcinoma

Gastric signet-ring cell carcinoma (GSRCC) is a subtype of gastric cancer with distinct phenotype and high risk of peritoneal metastasis. Studies have shown that early GSRCC has a good prognosis, while advanced GSRCC is insensitive to radiotherapy, chemotherapy or immune checkpoint blockade therapy. With technological advancement of single-cell RNA sequencing analysis and cytometry by time of flight mass cytometry, more detailed atlas of tumor microenvironment (TME) in GSRCC and its association with prognosis could be investigated extensively. Recently, two single-cell RNA sequencing studies revealed that GSRCC harbored a unique TME, manifested as highly immunosuppressive, leading to high immune escape. The TME of advanced GSRCC was enriched for immunosuppressive factors, including the loss of CXCL13⁺-cluster of differentiation 8⁺-Tex cells and declined clonal crosstalk among populations of T and B cells. In addition, GSRCC was mainly infiltrated by follicular B cells. The increased proportion of SRCC was accompanied by a decrease in mucosa-associated lymphoid tissue-derived B cells and a significant increase in follicular B cells, which may be one of the reasons for the poor prognosis of GSRCC. By understanding the relationship between immunosuppressive TME and poor prognosis in GSRCC and the underlying mechanism, more effective immunotherapy strategies and improved treatment outcomes of GSRCC can be anticipated.

Prognostic value of mismatch repair deficiency in patients receiving first-line fluoropyrimidine plus platinum for metastatic, recurrent, or unresectable gastric cancer

BACKGROUND

We examined the impact of mismatch repair (MMR) status on efficacy of first-line fluoropyrimidine plus platinum (FP) chemotherapy in patients with HER2-negative metastatic, recurrent, or unresectable gastric cancer (mGC).

METHODS

Patients with mGC receiving first-line FP between 2015 and 2018 at Asan Medical Center, Korea, were reviewed. We evaluated the clinical characteristics and the efficacy of chemotherapy according to MMR status in patients with available immunohistochemistry results.

RESULTS

Of 895 patients, we analyzed 543 with available MMR protein expression results, and deficient MMR (dMMR) was detected in 4.4% (n = 24). Patients with dMMR exhibited a significantly higher median age than those with proficient MMR (pMMR) (64 vs. 58 years, p = 0.044). No signet ring cell carcinoma (SRCC) was detected among dMMR tumors, whereas SRCC was found in 17.5% of pMMR. Objective response rate was 27.3% in dMMR and 34.3% in pMMR (p = 0.556). No difference in progression-free survival was noted between patients with dMMR and pMMR (median, 5.6 vs. 5.8 months, p = 0.266). Patients with dMMR tended to have better overall survival than those with pMMR although this difference was not statistically significant (median, 17.9 vs. 12.2 months, p = 0.183).

CONCLUSIONS

Efficacy of first-line FP was not different by MMR status in mGC patients.

Xenograft and organoid models in developing precision medicine for gastric cancer (Review)

Gastric cancer (GC), a highly heterogeneous disease, has diverse histological and molecular subtypes. For precision medicine, well‑characterized models encompassing the full spectrum of subtypes are necessary. Patient‑derived tumor xenografts and organoids serve as important preclinical models in GC research. The main advantage of these models is the retention of phenotypic and genotypic heterogeneity present in parental tumor tissues. Utilizing diverse sequencing techniques and preclinical models for GC research facilitates accuracy in predicting personalized clinical responses to anti‑cancer treatments. The present review summarizes the latest advances of these two preclinical models in GC treatment and drug response assessment.

Clinical Features of Gastric Signet Ring Cell Cancer: Results from a Systematic Review and Meta-Analysis

BACKGROUND

Conflicting results about the prognostic relevance of signet ring cell histology in gastric cancer have been reported. We aimed to perform a meta-analysis focusing on the clinicopathological features and prognosis of this subgroup of cancer compared with other histologies.

METHODS

A systematic literature search in the PubMed database was conducted, including all publications up to 1 October 2021. A meta-analysis comparing the results of the studies was performed.

RESULTS

A total of 2062 studies referring to gastric cancer with signet ring cell histology were identified, of which 262 studies reported on its relationship with clinical information. Of these, 74 were suitable to be included in the meta-analysis. A slightly lower risk of developing nodal metastases in signet ring cell tumours compared to other histotypes was found (especially to undifferentiated/poorly differentiated/mucinous and mixed histotypes); the lower risk was more evident in early and slightly increased in advanced gastric cancer. Survival tended to be better in early stage signet ring cell cancer compared to other histotypes; no differences were shown in advanced stages, and survival was poorer in metastatic patients. In the subgroup analysis, survival in signet ring cell cancer was slightly worse compared to non-signet ring cell cancer and differentiated/well-to-moderately differentiated adenocarcinoma.

CONCLUSIONS

Most of the conflicting results in signet ring cell gastric cancer literature could be derived from the lack of standardisation in their classification and the comparison with the different subtypes of gastric cancer. There is a critical need to strive for a standardised classification system for gastric cancer, fostering clarity and coherence in the forthcoming research and clinical applications.

Single-cell analysis of gastric signet ring cell carcinoma reveals cytological and immune microenvironment features

Gastric signet ring cell carcinoma (GSRC) is a special subtype of gastric cancer (GC) associated with poor prognosis, but an in-depth and systematic study of GSRC is lacking. Here, we perform single-cell RNA sequencing to assess GC samples. We identify signet ring cell carcinoma (SRCC) cells. Microseminoprotein-beta (MSMB) can be used as a marker gene to guide the identification of moderately/poorly differentiated adenocarcinoma and signet ring cell carcinoma (SRCC). The upregulated differentially expressed genes in SRCC cells are mainly enriched in abnormally activated cancer-related signalling pathways and immune response signalling pathways. SRCC cells are also significantly enriched in mitogen-activated protein kinase and oestrogen signalling pathways, which can interact and promote each other in a positive feedback loop. SRCC cells are shown to have lower cell adhesion and higher immune evasion capabilities as well as an immunosuppressive microenvironment, which may be closely associated with the relatively poor prognosis of GSRC. In summary, GSRC exhibits unique cytological characteristics and a unique immune microenvironment, which may be advantageous for accurate diagnosis and treatment.

Pancancer Analysis of Revealed TDO2 as a Biomarker of Prognosis and Immunotherapy

Background

Tryptophan 2,3-dioxygenase (TDO) encoded by TDO2, a rate-limiting enzyme in the kynurenine pathway, catabolizes tryptophan to kynurenine, evades immune surveillance, and promotes tumor growth. Although accumulating evidence suggests a crucial role of TDO2 during tumor formation and development, systematic evaluation of TDO2 across human cancers has rarely been reported.

Methods

To shed more light on the role of TDO2 in human cancer, we explored the expression profiles of TDO2 and identified its prognostic value in pancancer analysis through TCGA, CCLE, and GTEx databases. We further utilized TCGA data to evaluate the association between TDO2 and tumor immunological features, such as mismatch repair (MMR), tumor immune infiltration, immune checkpoint-related genes, tumor mutational burden (TMB), microsatellite instability (MSI), and DNA methyltransferase (DNMT).

Results

TDO2 exhibited different expression levels in various cancer cell lines. Frequently, TDO2 was detected to be highly expressed in the majority of cancers. In addition, high TDO2 expression was correlated with an unfavorable prognosis for patients in KIRP, LGG, TGCT, and UVM. Moreover, high TDO2 expression level positively correlated with higher immune infiltration, especially dendritic cells. Additionally, there is a close relationship between TDO2 and immune checkpoint-related gene markers, such as LAIR1, CD276, NRP1, CD80, and CD86. Finally, correlation analysis has demonstrated a high-correlation between TDO2 and TMB, MSI, MMR, and DNMT of multiple cancer types.

Conclusion

Therefore, our results suggest that TDO2 can function as a potential prognostic biomarker due to its role in tumor immunity regulation.

Prognostic significance of metastatic lymph node ratio in patients with gastric cancer after curative gastrectomy: a single-center retrospective study

BACKGROUND

The objective of this study was to evaluate the prognostic value of Metastatic lymph node ratio (MLNR) after curative gastrectomy in patients with gastric cancer (GC) and the potential for new indicators to strengthen the current guidelines.

METHODS

We retrospectively researched 3864 GC patients with curative gastrectomy between February 2011 and February 2016. The following clinical data were collected from the included patients: gender, type of gastrectomy, tumor location, T stage, N stage, ELN, tumor size, age at surgery, perineural invasion, vascular invasion, TNM stage, survival time and survival status. Patients were divided into low-MLNR (L-MLNR), and high-MLNR (H-MLNR) groups based on adjusted the X-tile cutoff-value of 0.25 for MLNR, the survival rates and clinicopathological characteristics of each group were compared. For the assessment of significant associations between clinicopathological characteristics and patients' survival, univariate and multivariate analyses were performed using the Kaplan-Meier method and Cox proportional hazards analysis. The log-rank test was used to examine the statistical significance of differences among different survival curves. Clinicopathological features significantly associated with MLNR were assessed by the Chi-square test and multinomial logistic regression. The discriminative ability was measured by calculating the Bayesian Information Criterion (BIC) values for each category. Assessment of the effect of clinicopathological features on MLNR for predicting prognosis of GC patients used stratum analysis through Kaplan-Meier analysis and Cox proportional risk Analysis.

RESULTS

Survival analysis indicated that MLNR was negatively associated with overall survival (OS) (p < .001) and was an independent prognostic predictor in 3864 GC patients (p < .001). MLNR had significant prognostic significance in various subgroups with clinicopathological characteristics (gender, type of gastrectomy, tumor location, T stage, N stage, ELN, tumor size, age at surgery, perineural invasion, vascular invasion, and TNM stage) (p < .001).

CONCLUSIONS

The MLNR may become a new indicator to assess the prognosis of GC patients who underwent curative gastrectomy. The results may have potential clinical implications that should be considered when developing clinical practice guidelines or the design of the future investigation.

CD3D Is an Independent Prognostic Factor and Correlates With Immune Infiltration in Gastric Cancer

The protein encoded by CD3D is part of the T-cell receptor/CD3 complex (TCR/CD3 complex) and is involved in T-cell development and signal transduction. Previous studies have shown that CD3D is associated with prognosis and treatment response in breast, colorectal, and liver cancer. However, the expression and clinical significance of CD3D in gastric cancer are not clear. In this study, we collected 488 gastric cancer tissues and 430 paired adjacent tissues to perform tissue microarrays (TMAs). Then, immunohistochemical staining of CD3D, CD3, CD4, CD8 and PD-L1 was conducted to investigate the expression of CD3D in gastric cancer and the correlation between the expression of CD3D and tumor infiltrating lymphocytes (TILs) and PD-L1. The results showed that CD3D was highly expressed in gastric cancer tissues compared with paracancerous tissues (P<0.000). Univariate and multivariate analyses showed that CD3D was an independent good prognostic factor for gastric cancer (P=0.004, HR=0.677, 95%CI: 0.510-0.898 for univariate analyses; P=0.046, HR=0.687, 95%CI: 0.474-0.994 for multivariate analyses). In addition, CD3D was negatively correlated with the tumor location, Borrmann type and distant metastasis (P=0.012 for tumor location; P=0.007 for Borrmann type; P=0.027 for distant metastasis). In addition, the expression of CD3D was highly positively correlated with the expression of CD3, CD4, CD8, and PD-L1, and the combination of CD3D with CD3, CD4, CD8 and PD-L1 predicted the best prognosis (P=0.043). In summary, CD3D may play an important regulatory role in the tumor immune microenvironment of gastric cancer and may serve as a potential indicator of prognosis and immunotherapy response.

The Prognostic Significance and Gene Expression Characteristics of Gastric Signet-Ring Cell Carcinoma: A Study Based on the SEER and TCGA Databases

Purpose

This study is based on the Surveillance, Epidemiology, and End Results (SEER) program to explore the prognostic differences between signet-ring cell carcinoma (SRC) and intestinal-type gastric carcinoma (ITGC). This study is also based on gene sequencing data from The Cancer Genome Atlas (TCGA) to identify unique genetic contributions to the prognostic differences between the two subtypes of gastric cancer.

Patients and Methods

The clinical data were based on the SEER database from 2004 to 2015. Kaplan–Meier (KM) curves were used to compare 5-year overall survival (OS), and Cox regression was used for univariate and multivariate analyses. Gene expression profiles were obtained from TCGA database, and differentially expressed genes (DEGs) were screened. Functional enrichment analysis, protein interaction and survival analysis will be further carried out. Genes of interest were verified by the Human Protein Atlas, immunohistochemistry, and encyclopedia of Cancer Cell Lines (CCLE). The relationship between genes of interest and immune cell infiltration was also analyzed by Tumor Immune Estimation Resource (TIMER).

Results

Compared with ITGC patients, SRC patients were more likely to be female, tended to be younger, and have a greater tumor distribution in the middle and lower stomach (p &lt; 0.01). SRCs showed a significantly better prognosis than ITGCs (p &lt; 0.01) in early gastric cancer (EGC), while the prognosis of SRCs was significantly worse than ITGCs (p &lt; 0.05) in advanced gastric cancer (AGC). A total of 256 DEGs were screened in SRCs compared to ITGCs, and the enrichment analysis and protein interactions revealed that differential genes were mainly related to extracellular matrix organization. Thrombospondin1 (THBS1) and serpin peptidase inhibitor, clade E, member 1 (SERPINE1) are significantly differentially expressed between SRC and ITGC, which has been preliminarily verified by immunohistochemistry and open-source databases. THBS1 and SERPINE1 are also associated with multiple immune cell infiltrates in gastric cancer.

Conclusions

There were significant differences in the clinicopathological features and prognosis between SRC and ITGC. These results suggest that SRC and ITGC may be two distinct types of tumors with different pathogeneses. We found many codifferentially expressed genes and important pathways between SRC and ITGC. THBS1 and SERPINE1 were significantly differentially expressed in the two types of gastric cancer, and may have potentially important functions.

Anatomic Subsites and Prognosis of Gastric Signet Ring Cell Carcinoma: A SEER Population-Based 1 : 1 Propensity-Matched Study

Background. The dismal prognosis of gastric signet ring cell carcinoma (GSRC) is a global problem. The current study is conducted to comprehensively evaluate clinicopathological features and survival outcomes in GSRC patients stratified by anatomic subsites. Then, predictive nomograms are constructed and validated to improve the effectiveness of personalized management. Method. The patients diagnosed with GSRC were recruited from the online SEER database. The influence of anatomic subsites on overall survival (OS) and cancer-specific survival (CSS) was evaluated using multivariate Cox regression and Kaplan-Meier analysis. Then, we employed propensity score matching (PSM) technique to decrease selection bias and balance patients’ epidemiological factors. Predictive nomograms were constructed and validated. Sensitivity analysis was performed to validate the conclusion. Results. Multivariate Cox regression demonstrated that the patients with overlapping gastric cancer (OGC) suffered the highest mortality risk for OS (HR, 1.29; 95% CI, 1.23-1.36; $P<0.001$ ) and CSS (HR, 1.33; 95% CI, 1.28-1.37; $P<0.001$ ). Age, TNM stage, tumor localization, tumor size, surgery, and chemotherapy presented a highly significant relationship with OS and CSS. Following subgroup and PSM analysis, OGC patients were confirmed to have the worst OS and CSS. Then, nomograms predicting 6-month, 12-month, and 36-month survival were constructed. The area under the curve (AUC) value in ROC was 0.775 (95% CI, 0.761-0.793) for 6-month survival, 0.789 (95% CI, 0.776-0.801) for 12-month survival, and 0.780 (95% CI, 0.765-0.793) for 36-month survival in the OS group, while in the CSS group, it was 0.771 (95% CI, 0.758-0.790) for 6-month survival, 0.781 (95% CI, 0.770-0.799) for 12-month survival, and 0.773 (95% CI, 0.762-0.790) for 36-month survival. Conclusion. We identified anatomic subsites as a predictor of survival in those with GSRC. Patients with OGC suffered the highest mortality risk. The proposed nomograms allowed a relatively accurate survival prediction for GSRC patients.

Soluble podoplanin as a biomarker in diffuse‑type gastric cancer

Diffuse‑type gastric cancer, also known as scirrhous gastric cancer, is characterized by a larger number of stromal cells, referred to as cancer‑associated fibroblasts (CAFs), than the number of cancer cells in the tissue. The present study focused on CAFs in gastric cancer and examined their potential as a blood biomarker. A total of 46 and 84 patients with gastric cancer were respectively included in a development and an independent validation cohort to assess the clinicopathological characteristics of plasma podoplanin (PDPN) levels. The prognostic impact of plasma PDPN was also investigated in the validation cohort. The cut‑off value of the plasma‑PDPN concentration was set to the median plasma PDPN concentration in the development cohort that was then divided into the high‑PDPN and low‑PDPN groups. The high‑PDPN group tended to have more diffuse‑type disease (P=0.079), which was further confirmed through logistic regression analysis (P=0.008). Kaplan‑Meier survival estimates indicated that the recurrence‑free survival rate was significantly lower in the high‑PDPN group (P=0.029). In conclusion, plasma soluble PDPN was demonstrated to be a marker for diffuse gastric cancer and may reflect the prognosis of this disease.

Immunohistochemical analysis of PD-L1 and tumor-infiltrating immune cells expression in the tumor microenvironment of primary signet ring cell carcinoma of the prostate

Primary signet ring cell carcinoma (SRCC) of the prostate is a rare neoplasm. However, its potential tumorigenic mechanism, clinicopathological features, and prognostic outcome have not been systematically described. To determine the pathogenic mechanism, we detected distributions of programmed cell death-ligand 1 (PD-L1), programmed death 1 (PD-1), and cellular components in the tumor microenvironment, including tumor-infiltrating lymphocytes (CD4 and CD8), tumor-associated macrophages (TAMs; CD163 and CD68), and tumor-associated fibroblasts (vimentin and alpha-smooth muscle actin [α-SMA]), in tumor tissues from four patients with primary prostatic SRCC compared with corresponding adjacent tissues and tumor tissues from 30 patients with prostate adenocarcinoma (PCa) by immunohistochemical staining. We found higher expression of PD-L1, CD163, and CD68 in primary SRCC specimens than that in both corresponding adjacent nontumor specimens and PCa specimens with different Gleason scores, indicating that TAMs may participate in the malignant biological behavior of primary SRCC of the prostate. For further analysis, we searched electronic journal databases and Surveillance, Epidemiology, and End Results (SEER) to identify 200 eligible patients including our four cases. According to Kaplan–Meier survival curve analysis, patients <68 years old, with radical prostatectomy (RP), Gleason score of 7–8, and lower clinical stage had longer overall survival (OS). Moreover, Cox multivariate analysis indicated that race (hazard ratio [HR] = 1.422), surgical approach (HR = 1.654), and Gleason score (HR = 2.162) were independent prognostic factors for OS. Therefore, primary SRCC of the prostate represents a distinct and aggressive subtype of prostate cancer associated with a higher distribution of PD-L1 and TAMs, which warrants further clinical investigation.

Establishment of gastric signet ring cell carcinoma organoid for the therapeutic drug testing

Signet ring cell carcinoma (SRCC) has specific oncogenesis and phenotypic and treatment resistance heterogeneity. Systemic therapies are often ineffective, and predictive biomarkers to guide treatment are urgently needed. Tumor organoids have recently emerged as an ideal model for drug testing and screening. Here, we report gastric organoids established from tumor tissues comprising four SRCCs and eight non-SRCCs. Tumor organoids demonstrated different growth characteristics and morphologies. Changes in the original tumor genome were maintained during long-term culture from whole-exome sequencing (WES) analysis. Immunohistochemistry and H&E staining showed that the tissue characteristics of the primary tumor could be recapitulated. In addition, organoid lines successfully formed tumors in immunodeficient mice and maintained tumorigenic character. Different responses to 5-fluorouracil, oxaliplatin, docetaxel and irinotecan treatment were observed in SRCC and non-SRCC organoids. These results demonstrate that gastric organoid drug models, including SRCC, were highly similar to the original tumors in phenotypic and genotypic profiling and could be as living biomarkers for drug response testing.

FGFR2 alteration as a potential therapeutic target in poorly cohesive gastric carcinoma

Background

Poorly cohesive (PC) is a unique histologic subtype of gastric cancer (GC), with an increasing incidence in recent years. However, the molecular characteristics and therapeutic targets of PC GC are not yet well studied and there are no effective therapies for these patients.

Methods

Formalin fixed paraffin embedded (FFPE) samples of 556 GC patients, including 64 PC GC, were collected for next-generation sequencing (NGS). Clinical characteristics and genomic profiling were analyzed. FGFR2 expression was detected by quantitative real time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). FGFR2 inhibitors response was studied in vitro.

Results

Among 556 GC patients, PC GC patients were younger (P = 0.004), had lower tumor mutation burden (TMB-L) (P = 0.001) than non-PC GC. The top 10 most frequently mutated genes in PC GC were TP53 (48%), CDH1 (31%), ARID1A (14%), FGFR2 (14%), ERBB2 (9%), CDKN2A (9%), FGF3 (8%), LRP1B (9%), FGF19 (8%) and FGF4 (8%). Noticeably, FGFR2 is more frequently mutated than non-PC GC (14% vs. 6%, P = 0.037), including copy number variants (CNVs, 12.5%) and gene rearrangements (3.1%, FGFR2/VTI1A and FGFR2/TACC2). Former studies have confirmed that gain of copy number could increase FGFR2 expression and sensitivity to FGFR2 inhibitors in GC. However, no research has verified the function of FGFR2 rearrangements in GC. Our results showed that cell lines of GC transfected with TACC2-FGFR2 fusion had increased mRNA and protein expression of FGFR2, and were more sensitive to FGFR2 inhibitors. FGFR2 inhibitors might be a new therapeutic target for PC GC. In addition, we found patients of PC GC harboring gene rearrangements (n = 9) had poorer overall survival (OS) in comparison with patients without any gene rearrangement (n = 19) (16.0 months vs 21.0 months, P = 0.043). Gene rearrangement might be an adverse prognostic factor for PC GC patients.

Conclusions

FGFR2 alterations were recurrent in PC GC and FGFR2 inhibitors might be a new therapeutic target for PC GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03079-8.

Prognosis and Biological Behavior of Gastric Signet-Ring Cell Carcinoma Better or Worse: A Meta-Analysis

BACKGROUND

The clinical pathology of gastric signet-ring cell carcinoma (SRC) is still unclear. This meta-analysis was performed to evaluate the difference in biological behavior and prognosis between SRC and non-signet ring cell carcinoma (NSRC).

METHODS

A total of 58 eligible studies were analyzed using RevMan and other auxiliary software. Biological behaviors were compared based on odds ratio (OR) and mean difference (MD). Hazards ratio (HR) was calculated for prognosis based on Kaplan-Meier curves.

RESULTS

Totally, 28,946 SRC patients were compared with 81,917 NSRC patients. Compared with NSRC patients, lower male: female ratio (OR = 0.53, P < 0.01), younger age (MD = -4.89, P < 0.01), more middle location (OR = 1.64, P < 0.01), more depressed type at early stage (OR = 1.31, P < 0.05), higher incidence of Borrmann type IV (OR = 1.96, P < 0.01), less lymph node metastasis at early stage (OR = 0.78, P < 0.05), better prognosis at early stage (HR = 0.59, P < 0.01), and worse prognosis at advanced stage (HR = 1.19, P < 0.01) were associated with SRC patients.

CONCLUSION

The prognosis of SRC at early stage is better than other types of gastric cancer, while that of SRC at advanced stage is relatively poorer.

Characterization and clinical evaluation of microsatellite instability and loss of heterozygosity in tumor-related genes in gastric cancer

Microsatellite instability (MSI) detection is widely used in the diagnosis and prognosis evaluation of colorectal cancer. However, for gastric cancer (GC), there is no standard panel of microsatellites (MSs) used in clinical guidance. The present study aimed to identify useful predictors of the clinical features and for the prognosis of GC, based on an investigation of MSI and loss of heterozygosity (LOH) in tumor-related genes. First, from 20 tumor-related genes which were proven to be important to the development of GC, 91 MSs were identified, and PCR amplification, short tandem repeat scanning analysis and TA clone sequencing were used to analyze MSI and LOH in the first set of 90 GC samples. Subsequently, the same method was used to detect the MSI/LOH of the optimized loci in the second set of 136 GC samples. MSI/LOH in the mismatch repair genes was highly consistent with that in oncogenes and tumor suppressor genes, respectively. The length of the core sequence was a main factor for the MSI/LOH rate. The MSI of 12 single loci was significantly associated with lymph node metastasis. The MSI in TP53-1 and the LOH in MGMT-10 were significantly associated with early stages of tumor infiltration depth. The LOH in MGMT-10, PTN-2 and MCC-17 was significantly associated with TNM stage. The LOH in TP53-1 and ERBB2-12 was associated with adenocarcinoma. The MSI/LOH in 6 single loci of 5 tumor-related genes was associated with poor prognosis of GC. The present study demonstrated that the MSI/LOH of loci in tumor-associated genes was associated with 4 clinicopathological characteristics and outcomes of GC. These results may provide potential specific biomarkers for the clinical prediction and treatment of GC.

Is there still a place for conventional histopathology in the age of molecular medicine? Laurén classification, inflammatory infiltration and other current topics in gastric cancer diagnosis and prognosis

Gastric cancer (GC) is the fifth most common cancer and the third cause of cancer-related deaths worldwide. In western countries, more than half of GC patients are diagnosed at advanced stages and 5-year survival rates range between 20-30%. The only curative treatment is surgery, and despite recent advances in oncological therapies, GC prognosis is still poor. The main prognostic tool for patient categorization and treatment selection is the TNM classification, but its limitations are being increasingly recognized. Early recurrences may occur in early-stage disease, and patients at the same stage show heterogeneous outcomes. Thus, there is a need to improve GC stratification and to identify new prognostic factors, which may allow us to select drug-susceptible populations, refine patient grouping for clinical trials and discover new therapeutic targets. Molecular classifications have been developed, but they have not been translated to the clinical practice. On the other hand, histological assessment is cheap and widely available, and it is still a mainstay in the era of molecular medicine. Furthermore, histological features are acquiring new roles as reflectors of the genotype-phenotype correlation, and their potential impact on patient management is currently being analyzed. The aim of this literature review is to provide a modern overview of the histological assessment of GC. In this study, we discuss recent topics on the histological diagnosis of GC, focusing on the current role of Laurén classification and the potential value of new histological features in GC, such as inflammatory infiltration and tumor budding.

Primary Pancreatic Signet Ring Cell Carcinoma: A Case Report and Review of the Literature

Background: Primary pancreatic signet ring cell carcinoma (PPSRCC) is a rare (<1%) poorly reported histopathological variant of pancreatic cancer with ill-defined treatment guidelines. Herein, we describe a case of nonmetastatic PPSRCC in a 45-year-old female.

Presentation: A 45-year-old female presented with 3 weeks of abdominal pain radiating to her back. Other pertinent positives included a 20-pound (9.1-kilogram) weight loss and jaundice, with a known 30-pack-year smoking history. CT scan revealed a 4.6 × 3.6 cm hypoattenuating mass in the head of the pancreas (HOP) with dilatation of the common bile duct. Total bilirubin at presentation was elevated, and a biliary stent was placed endoscopically. Subsequent endoscopic ultrasonography revealed a periampullary ulcerated mass involving the HOP and second portion of the duodenum, with pathology revealing poorly differentiated adenocarcinoma with mucinous background and focal signet ring cells. A classic pancreatoduodenectomy (Whipple procedure) was performed. Final pathology revealed a poorly differentiated (G3) pT3/pN2/pM0 PPSRCC with 11 of 16 positive specimen lymph nodes. The tumor had evidence of both KRAS and TP53 mutations and expressed an MUC1+/MUC2-/MUC5AC+ immunophenotype. Medical oncology recommended a 6-month course of adjuvant modified-dose FOLFIRINOX therapy.

Conclusion: This report highlights the need for further research into the pathogenesis of gastrointestinal signet ring cell carcinoma to identify and study therapeutic targets that can eventually be translated to PPSRCC treatment. Given the paucity of PPSRCC, adjuvant therapy candidates follow the current literature on more common pancreatic cancer subtypes to guide treatment.