Genomic and transcriptomic profiling of hepatoid adenocarcinoma of the stomach

Immune evasion strategies in AFP-producing gastric carcinoma: characterized by HLA-G expression and HLA class I deficiency

Alpha-fetoprotein-producing gastric carcinoma (AFPGC) is an aggressive subtype of gastric cancer characterized by a primitive cellular phenotype and poor prognosis. The tumor immunology of AFPGC remains largely unexplored. Given its embryonic-like properties, AFPGC is hypothesized to employ distinct immune evasion strategies, with the oncofetal protein human leukocyte antigen (HLA)-G-a key mediator of maternal-fetal immune tolerance-likely playing a pivotal role. To test this, we assessed the expression of HLA-G, along with other key immune evasion markers, including HLA class I (HLA-I) deficiency and PD-L1 expression, in 39 cases of AFPGC, and compared them with those of 44 Epstein-Barr virus (EBV)-positive, 57 microsatellite instability (MSI), 54 intestinal-type, and 45 diffuse-type gastric carcinomas. HLA-G expression was significantly higher in AFPGCs (71%) than in other subtypes (7-28%; P < 0.001). HLA-I deficiency (≥ 1% of tumor cells) was most prevalent in AFPGC (69%), followed by MSI tumors (56%), with lower rates in other subtypes (22-29%). PD-L1 positivity (combined positive score ≥ 5) was observed in 41% of AFPGCs, lower than in EBV-positive (77%) and MSI tumors (44%), but higher than in intestinal-type (13%) and diffuse-type (9%) carcinomas. Furthermore, CD8-positive T-cell infiltration was found to be lowest in AFPGC compared to the other subtypes. These findings suggest that AFPGC employs multiple immune evasion mechanisms, notably through increased HLA-G expression and HLA-I deficiency, likely linked to its primitive cellular phenotype and reactivation of immunogenic oncofetal antigens. Such immune evasion features may underlie the aggressiveness of AFPGC and present promising targets for immunotherapeutic interventions.

Hepatoid adenocarcinoma of the stomach with enteroblast differentiation: A case report

BACKGROUND

Hepatoid adenocarcinoma of the stomach (HAS) is a rare subtype of stomach carcinoma without specific clinical or endoscopic manifestations. The pathology is characterized by the presence of both gastric adenocarcinoma and hepatocellular carcinoma differentiation regions in the tumor tissue with some characteristic immunohistochemical markers. Here, we report a rare case of HAS with enteroblast differentiation in an elderly woman.

CASE SUMMARY

A patient was found to have elevated alpha-fetoprotein during a physical examination. The patient was pathologically confirmed to have HAS with enteroblast differentiation after subtotal gastrectomy.

CONCLUSION

HAS represents an uncommon subclassification of gastric cancer devoid of distinctive clinical manifestations. It is distinguished by the coexistence of gastric adenocarcinoma and hepatocellular carcinomatoid differentiation within the tumor tissue, presenting a unique histopathological profile. Given its scarcity in clinical practice, pathological diagnosis remains the definitive gold standard for identifying this entity.

Targeting amino acid metabolism to inhibit gastric cancer progression and promote anti-tumor immunity: a review

The incidence of gastric cancer remains high and poses a serious threat to human health. Recent comprehensive investigations into amino acid metabolism and immune system components within the tumor microenvironment have elucidated the functional interactions between tumor cells, immune cells, and amino acid metabolism. This study reviews the characteristics of amino acid metabolism in gastric cancer, with a particular focus on the metabolism of methionine, cysteine, glutamic acid, serine, taurine, and other amino acids. It discusses the relationship between these metabolic processes, tumor development, and the body's anti-tumor immunity, and analyzes the importance of targeting amino acid metabolism in gastric cancer for chemotherapy and immunotherapy.

Hepatoid adenocarcinoma of the stomach with ideal response to neoadjuvant chemo-immunotherapy: a case report

Hepatoid adenocarcinoma of the stomach (HAS) is a rare subtype of gastric cancer characterized by histological features resembling hepatocellular carcinoma. Surgical intervention remains the preferred treatment modality for eligible patients. However, the efficacy of neoadjuvant therapy and alternative treatment regimens has been found to be suboptimal. Consequently, due to the high metastatic potential and unfavorable biological behavior of HAS, the prognosis for affected patients is exceedingly poor. We present a case involving a 64-year-old male diagnosed with advanced HAS, who demonstrated significant antitumor responses following a preoperative regimen of chemotherapy combined with immunotherapy, specifically utilizing oxaliplatin, S-1, and sintilimab. Over a 2-month period of neoadjuvant therapy, the patient's serum α-fetoprotein level significantly decreased from 52,951.56 ng/mL to 241.04 ng/mL. Computed tomography scans revealed substantial tumor regression. Subsequent radical surgical intervention confirmed significant tumor shrinkage, with no evidence of lymph node metastasis upon pathological examination. This is the first report of chemotherapy combined with sintilimab in the treatment of gastric hepatoid adenocarcinoma, which may provide novel insights into the therapeutic strategy for HAS.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

Clinicopathological features of hepatoid adenocarcinoma and non-hepatoid adenocarcinoma of the stomach: A systematic review and meta-analysis

BACKGROUND

Hepatoid adenocarcinoma of the stomach (HAS) is an extremely rare and unique malignant gastric tumor with a significantly worse prognosis than non-hepatoid adenocarcinoma of the stomach (non-HAS). The present study explored the clinicopathological features of HAS and non-HAS patients to provide insights into HAS treatment strategies.

METHODS

From December 26, 2023, we performed a comprehensive search of the PubMed, Web of Science, Cochrane Library, and Embase.com databases for relevant studies. Two authors independently screened the studies, evaluated their quality, extracted data, and performed the analyses. This study was registered with PROSPERO on January 2, 2024.

RESULTS

Nine retrospective studies were included for analysis after screening 833 articles. A total of 350 and 924 patients were enrolled in the HAS and non-HAS groups, respectively. While no significant differences were observed in age, sex, tumor size, T3 or T4 stage, and N2 or N3 stage between the two groups, the HAS group exhibited higher rates of lymph node metastasis (OR = 1.93, 95% CI: 1.19-3.13, p = 0.007), liver metastasis (OR = 3.45, 95% CI: 2.26-5.28, p < 0.001), and vascular invasion (OR = 2.76, 95% CI: 2.05-3.71, p < 0.001). Additionally, the HAS group had lower 3-year survival rates (HR = 2.35, 95% CI: 1.70-3.25, p < 0.001) and 5-year survival rates (HR = 3.63, 95% CI: 1.49-8.88, p = 0.005), but lower rates of lymphatic permeation (OR = 0.68, 95% CI: 0.47-0.99, p = 0.040).

CONCLUSION

Based on the current clinical evidence, patients with HAS present distinct clinicopathological features, greater invasiveness, and poorer prognosis than non-HAS patients. Further research is warranted to develop optimal treatment strategies for HAS.

Gastric cancer immunosuppressive microenvironment heterogeneity: implications for therapy development

Although immunotherapy has revolutionized solid tumor treatment, durable responses in gastric cancer (GC) remain limited. The heterogeneous tumor microenvironment (TME) facilitates immune evasion, contributing to resistance to conventional and immune therapies. Recent studies have highlighted how specific TME components in GC acquire immune escape capabilities through cancer-specific factors. Understanding the underlying molecular mechanisms and targeting the immunosuppressive TME will enhance immunotherapy efficacy and patient outcomes. This review summarizes recent advances in GC TME research and explores the role of the immune-suppressive system as a context-specific determinant. We also provide insights into potential treatments beyond checkpoint inhibition.

Exploration of molecular markers related to chemotherapy efficacy of hepatoid adenocarcinoma of the stomach

PURPOSE

Preoperative neoadjuvant chemotherapy may not improve the prognosis of patients with hepatoid adenocarcinoma of the stomach (HAS), a rare pathological type of gastric cancer. Thus, the study aimed at the genomic and transcriptomic impacts of preoperative chemotherapy on HAS.

METHODS

Patients with HAS who underwent surgical resection at Peking University Cancer Hospital were retrospectively included in this study. Whole exome sequencing and transcriptome sequencing were performed on pre-chemotherapy, non-chemotherapy and post-chemotherapy samples. We then compared the alterations in molecular markers between the post-chemotherapy and non-chemotherapy groups, and between the chemotherapy-effective and chemotherapy-ineffective groups, respectively.

RESULTS

A total of 79 tumor samples from 72 patients were collected. Compared to the non-chemotherapy group, the mutation frequencies of several genes were changed after chemotherapy, including TP53. In addition, there was a significant increase in the frequency of frameshift mutations and cytosine transversion to adenine (C > A), appearance of COSMIC signature 6 and 14, and a reduced gene copy number amplification. Interestingly, the same phenomenon was observed in chemotherapy-ineffective patients. In addition, many HAS patients had ERBB2, FGFR2, MET and HGF gene amplification. Moreover, the expression of immune-related genes, especially those related to lymphocyte activation, was down-regulated after chemotherapy.

CONCLUSION

Chemotherapy is closely associated with changes in the molecular characteristics of HAS. After chemotherapy, at genomic and transcriptome level, many features were altered. These changes may be molecular markers of poor chemotherapeutic efficacy and play an important role in chemoresistance in HAS. In addition, ERBB2, FGFR2, MET and HGF gene amplification may be potential therapeutic targets for HAS.

Exploring the current landscape of single-cell RNA sequencing applications in gastric cancer research

Gastric cancer (GC) represents a major global health burden and is responsible for a significant number of cancer-related fatalities. Its complex nature, characterized by heterogeneity and aggressive behaviour, poses considerable challenges for effective diagnosis and treatment. Single-cell RNA sequencing (scRNA-seq) has emerged as an important technique, offering unprecedented precision and depth in gene expression profiling at the cellular level. By facilitating the identification of distinct cell populations, rare cells and dynamic transcriptional changes within GC, scRNA-seq has yielded valuable insights into tumour progression and potential therapeutic targets. Moreover, this technology has significantly improved our comprehension of the tumour microenvironment (TME) and its intricate interplay with immune cells, thereby opening avenues for targeted therapeutic strategies. Nonetheless, certain obstacles, including tumour heterogeneity and technical limitations, persist in the field. Current endeavours are dedicated to refining protocols and computational tools to surmount these challenges. In this narrative review, we explore the significance of scRNA-seq in GC, emphasizing its advantages, challenges and potential applications in unravelling tumour heterogeneity and identifying promising therapeutic targets. Additionally, we discuss recent developments, ongoing efforts to overcome these challenges, and future prospects. Although further enhancements are required, scRNA-seq has already provided valuable insights into GC and holds promise for advancing biomedical research and clinical practice.

Hepatoid adenocarcinoma in ureter with next-generation sequencing: A case report and literature review

BACKGROUND

Hepatoid adenocarcinoma (HAC) is rare in the urinary system, with only 7 reported cases in upper urinary tract. This report aimed to explore the genetic characteristics of ureteral HAC for first time, and to describe the treatment prognosis of ureteral HAC.

CASE PRESENTATION

We present a rare case of ureteral HAC in a 53-year-old female, showing elevated serum levels of AFP and CEA, prolonged chronic irritation may be an important cause of her ureteral HAC. Radical nephroureterectomy was performed, the serum levels of AFP and CEA decreased significantly, and metastasis in lymph nodes was found at 9 months after surgery, she had no related symptoms after 18 months postoperatively without adjuvant chemotherapy. Three driver somatic mutations in cancer were identified by NGS testing, including: TP53D281H, KMT2DL1211Ifs*2, KMT2DT1843Nfs*5, demonstrating that ureteral HAC has the similar mutational features to upper tract urothelial carcinoma. Homologous-recombination deficiency (HRD) was positive in this tumor with no mutations in HRD-related genes, which was possibly induced by the copy number deletion of SETD2 gene.

CONCLUSIONS

We report a rare case of ureteral HAC with elevated serum levels of AFP and CEA. NGS testing demonstrated that ureteral HAC has the similar mutational features to upper tract urothelial carcinoma, which is an important guide for the diagnosis and treatment of ureteral HAC.

Immunohistochemical characteristics and potential therapeutic regimens of hepatoid adenocarcinoma of the stomach: a study of 139 cases

Hepatoid adenocarcinoma of stomach (HAS) is a special subtype of gastric cancer with poor prognosis. Immunohistochemical analysis could provide important clues for the treatment of HAS. A total of 159 patients were diagnosed as HAS and 139 were enrolled in this study. Statistical differences were determined using relative test methods and survival analyses were performed by the Kaplan-Meier method to find survival differences. All tumors in this study were negative for Epstein-Barr virus-encoded small RNAs (EBERs) and almost all showed no loss of mismatch repair (MMR) proteins and were positive for alpha fetoprotein (AFP or spalt like transcription factor 4 (SALL4). About half of the tumors had a positive programmed death-ligand 1 combined positive score (CPS) and 17.3% were positive for human epidermal growth factor receptor 2 (HER2). In addition, there was a relatively high proportion of cmet expression. We also found that HAS patients with recurrent disease treated by emerging therapy had a better survival than those treated with traditional chemotherapy (p = 0.002, median recurrence-to-death survival: 23 months versus 6 months); HAS patients who received anti-HER2 therapy or harbored MMR deficiency had favorable prognosis. Overall, high proportions of MMR protein proficiency, positivity for AFP or SALL4, overexpression of HER2, CPS and cmet, as well as negative EBER findings, are distinctive characteristics of HAS patients. While negative EBER and MMR proficiency indicate molecular features of HAS, positivity for AFP or SALL4 could aid in the diagnosis of HAS. In addition, HAS patients could benefit from anti-HER2 therapy, immunotherapy, and anti-angiogenesis therapy.

Single-cell RNA-seq reveals novel immune-associated biomarkers for predicting prognosis in AML patients with RUNX1::RUNX1T1

Acute myeloid leukemia (AML) with t(8;21)(q22;q22);(RUNX1::RUNX1T1) is highly heterogeneous and malignant. It has a relapse rate of nearly 40 %, resulting in clinical resistance or refractoriness to chemotherapy. Immune cells, particularly CD4(+) T and CD8(+) T lymphocytes, have been discovered to be dysfunctional in this condition, and functional recovery shows promising efficiency in preclinical trials. Here, with single-cell transcriptomic data from de novo AML patients with RUNX1::RUNX1T1 and at various stages following disease progression, we investigated the genes correlated with T-cell proliferation and activation. In leukemia cells, ADA, AHCY, GPN3 and LTBR were markedly highly expressed compared to those in T-cell at diagnosis, and they tended to increase with disease progression. Additionally, we discovered that AHCY was an effective biomarker to predict the overall survival as well as relapse-free survival of AML patients with RUNX1::RUNX1T1. The correlation of AHCY with infiltrated immune cells and immune checkpoints was also investigated. AML cohorts from two other independent studies, TCGA LAML (n = 145) and the GEO dataset (n = 104), also demonstrated an inferior outcome for AML patients with high AHCY expression. In conclusion, our research revealed that AHCY might function as a novel indicator to predict the prognosis and efficiency of T-cell proliferation and activation in AML patients with RUNX1::RUNX1T1.

Analysis of enhanced CT imaging signs and clinicopathological prognostic factors in hepatoid adenocarcinoma of stomach patients with radical surgery: a retrospective study

BACKGROUND

To investigate the association between CT signs and clinicopathological features and disease recurrence in patients with hepatoid adenocarcinoma of stomach (HAS).

METHODS

Forty nine HAS patients undergoing radical surgery were retrospectively collected. Association between CT and clinicopathological features and disease recurrence was analyzed. Multivariate logistic model was constructed and evaluated for predicting recurrence by using receiver operating characteristic (ROC) curve. Survival curves between model-defined risk groups was compared using Kaplan-Meier method.

RESULTS

24(49.0%) patients developed disease recurrence. Multivariate logistic analysis results showed elevated serum CEA level, peritumoral fatty space invasion and positive pathological vascular tumor thrombus were independent factors for disease recurrence. Odds ratios were 10.87 (95%CI, 1.14-103.66), 6.83 (95%CI, 1.08-43.08) and 42.67 (95%CI, 3.66-496.85), respectively. The constructed model showed an area under ROC of 0.912 (95%CI,0.825-0.999). The model-defined high-risk group showed poorer overall survival and recurrence-free survival than the low-risk group (both P < 0.001).

CONCLUSIONS

Preoperative CT appearance of peritumoral fatty space invasion, elevated serum CEA level, and pathological vascular tumor thrombus indicated poor prognosis of HAS patients.

Exploring the molecular characteristics of the malignant potential of gastric adenocarcinoma with enteroblastic differentiation

AIMS

Gastric adenocarcinoma with enteroblastic differentiation (GAED) is a rare subset of alpha-fetoprotein (AFP)-producing carcinomas with poor prognosis. However, the molecular features associated with the malignant potential of GEAD remain partially elucidated.

METHODS AND RESULTS

In this study, the relationship between clinicopathological parameters and aggressive biological behaviour was analysed in 37 patients with GAED. The results showed that GAED tended to infiltrate the deep layer of the gastric wall and possessed more frequent vascular invasion than conventional gastric adenocarcinoma (CGA) (P < 0.001). All distant metastases were observed in the GAED group, not the CGA group (P < 0.001). High HER2 expression was found in nearly 24.32% of the informative cases, and none showed EBV-encoded RNA positivity or deficient mismatch repair. The most frequently mutated gene in GAED was p53. Programmed cell death-ligand 1 (PD-L1) immunostaining revealed 13 patients with a combined positive score (CPS) ≥ 5 (65%, 13 of 20). Thus, based on these molecular markers (immunostaining, in situ hybridisation and mutation analysis), GAED may be classified as a unique subgroup of the chromosomal instability subtype with HER2+ /EBV- /MSS/TP53+ /PD-L1+ . Next-generation sequencing analyses showed that mutations in the TOPI, ELOA and NOTCH3 genes were found only in GAED, and abnormally expressed genes in GAED were significantly enriched in hepatocellular carcinoma-, gland development-, and gastric cancer-related pathways.

CONCLUSION

The HER2+ /EBV- /MSS/TP53+ /PD-L1+ profile and hepatocellular carcinoma-related pathways may be significant in the malignant potential of GAED. In addition to anti-HER2 therapy, immune check-point inhibitors may be an effective treatment option for patients with GAED.

Hepatoid adenocarcinoma of the stomach with neuroendocrine differentiation: A case report and review of literature

BACKGROUND

Both hepatoid adenocarcinoma of the stomach (HAS) and neuroendocrine differentiation (NED) are rare histological subtypes of gastric cancer with unique clinicopathological features and unfavorable outcomes. HAS with NED is even rarer.

CASE SUMMARY

Here, we report a 61-year-old man with HAS with NED, as detected by gastric wall thickening by positron emission tomography/computed tomography for a pulmonary nodule. Distal gastrectomy was performed, and pathological examination led to the diagnosis of HAS with NED. However, liver metastases occurred 6 mo later despite adjuvant chemotherapy, and the patient died 27 mo postoperatively.

CONCLUSION

We treated a patient with HAS with NED who underwent adjuvant chemotherapy after radical surgery and still developed liver metastases. We first report the detailed processes of the treatment and development of HAS with NED, providing an important reference for the clinical diagnosis and treatment of this condition.

Hepatoid adenocarcinoma of the stomach with neuroendocrine differentiation: A case report and review of literature

BACKGROUND

Both hepatoid adenocarcinoma of the stomach (HAS) and neuroendocrine differentiation (NED) are rare histological subtypes of gastric cancer with unique clinicopathological features and unfavorable outcomes. HAS with NED is even rarer.

CASE SUMMARY

Here, we report a 61-year-old man with HAS with NED, as detected by gastric wall thickening by positron emission tomography/computed tomography for a pulmonary nodule. Distal gastrectomy was performed, and pathological examination led to the diagnosis of HAS with NED. However, liver metastases occurred 6 mo later despite adjuvant chemotherapy, and the patient died 27 mo postoperatively.

CONCLUSION

We treated a patient with HAS with NED who underwent adjuvant chemotherapy after radical surgery and still developed liver metastases. We first report the detailed processes of the treatment and development of HAS with NED, providing an important reference for the clinical diagnosis and treatment of this condition.

Mapping the tumor microenvironment in clear cell renal carcinoma by single-cell transcriptome analysis

Introduction: Clear cell renal cell carcinoma (ccRCC) is associated with unfavorable clinical outcomes. To identify viable therapeutic targets, a comprehensive understanding of intratumoral heterogeneity is crucial. In this study, we conducted bioinformatic analysis to scrutinize single-cell RNA sequencing data of ccRCC tumor and para-tumor samples, aiming to elucidate the intratumoral heterogeneity in the ccRCC tumor microenvironment (TME). Methods: A total of 51,780 single cells from seven ccRCC tumors and five para-tumor samples were identified and grouped into 11 cell lineages using bioinformatic analysis. These lineages included tumor cells, myeloid cells, T-cells, fibroblasts, and endothelial cells, indicating a high degree of heterogeneity in the TME. Copy number variation (CNV) analysis was performed to compare CNV frequencies between tumor and normal cells. The myeloid cell population was further re-clustered into three major subgroups: monocytes, macrophages, and dendritic cells. Differential expression analysis, gene ontology, and gene set enrichment analysis were employed to assess inter-cluster and intra-cluster functional heterogeneity within the ccRCC TME. Results: Our findings revealed that immune cells in the TME predominantly adopted an inflammatory suppression state, promoting tumor cell growth and immune evasion. Additionally, tumor cells exhibited higher CNV frequencies compared to normal cells. The myeloid cell subgroups demonstrated distinct functional properties, with monocytes, macrophages, and dendritic cells displaying diverse roles in the TME. Certain immune cells exhibited pro-tumor and immunosuppressive effects, while others demonstrated antitumor and immunostimulatory properties. Conclusion: This study contributes to the understanding of intratumoral heterogeneity in the ccRCC TME and provides potential therapeutic targets for ccRCC treatment. The findings emphasize the importance of considering the diverse functional roles of immune cells in the TME for effective therapeutic interventions.

Single-cell transcriptome sequencing reveals heterogeneity of gastric cancer: progress and prospects

Gastric cancer is one of the most serious malignant tumor and threatens the health of people worldwide. Its heterogeneity leaves many clinical problems unsolved. To treat it effectively, we need to explore its heterogeneity. Single-cell transcriptome sequencing, or single-cell RNA sequencing (scRNA-seq), reveals the complex biological composition and molecular characteristics of gastric cancer at the level of individual cells, which provides a new perspective for understanding the heterogeneity of gastric cancer. In this review, we first introduce the current procedure of scRNA-seq, and discuss the advantages and limitations of scRNA-seq. We then elaborate on the research carried out with scRNA-seq in gastric cancer in recent years, and describe how it reveals cell heterogeneity, the tumor microenvironment, oncogenesis and metastasis, as well as drug response in to gastric cancer, to facilitate early diagnosis, individualized therapy, and prognosis evaluation.

Spatially resolved multi-omics highlights cell-specific metabolic remodeling and interactions in gastric cancer

Mapping tumor metabolic remodeling and their spatial crosstalk with surrounding non-tumor cells can fundamentally improve our understanding of tumor biology, facilitates the designing of advanced therapeutic strategies. Here, we present an integration of mass spectrometry imaging-based spatial metabolomics and lipidomics with microarray-based spatial transcriptomics to hierarchically visualize the intratumor metabolic heterogeneity and cell metabolic interactions in same gastric cancer sample. Tumor-associated metabolic reprogramming is imaged at metabolic-transcriptional levels, and maker metabolites, lipids, genes are connected in metabolic pathways and colocalized in the heterogeneous cancer tissues. Integrated data from spatial multi-omics approaches coherently identify cell types and distributions within the complex tumor microenvironment, and an immune cell-dominated "tumor-normal interface" region where tumor cells contact adjacent tissues are characterized with distinct transcriptional signatures and significant immunometabolic alterations. Our approach for mapping tissue molecular architecture provides highly integrated picture of intratumor heterogeneity, and transform the understanding of cancer metabolism at systemic level.

Hepatoid adenocarcinoma-Clinicopathological features and molecular characteristics

Hepatoid adenocarcinoma (HAC) is a rare, malignant, extrahepatic tumor with histologic features similar to those of hepatocellular carcinoma. HAC is most often associated with elevated alpha-fetoprotein (AFP). HAC can occur in multiple organs, including the stomach, esophagus, colon, pancreas, lungs, and ovaries. HAC differs greatly from typical adenocarcinoma in terms of its biological aggression, poor prognosis, and clinicopathological characteristics. However, the mechanisms underlying its development and invasive metastasis remain unclear. The purpose of this review was to summarize the clinicopathological features, molecular traits, and molecular mechanisms driving the malignant phenotype of HAC, in order to support the clinical diagnosis and treatment of HAC.

Integrative analysis reveals a clinicogenomic landscape associated with liver metastasis and poor prognosis in hepatoid adenocarcinoma of the stomach

Hepatoid adenocarcinoma of the stomach (HAS) is a rare subtype of gastric cancer (GC) that histologically resembles hepatocellular carcinoma (HCC). Despite its low incidence, HAS had a poor 5-year survival rate. Currently, the linkages between clinicopathological and genomic features of HAS and its therapeutic targets remain largely unknown. Herein, we enrolled 90 HAS patients and 270 stage-matched non-HAS patients from our institution for comparing clinicopathological features. We found that HAS had worse overall survival and were more prone to develop liver metastasis than non-HAS in our cohort, which was validated via meta-analysis. By comparing whole-exome sequencing data of HAS (n=30), non-HAS (n=63), and HCC (n=355, The Cancer Genome Atlas), we identified a genomic landscape associated with unfavorable clinical features in HAS, which contained frequent somatic mutations and widespread copy number variations. Notably, signaling pathways regulating pluripotency of stem cells affected by frequent genomic alterations might contribute to liver metastasis and poor prognosis in HAS patients. Furthermore, HAS developed abundant multiclonal architecture associated with liver metastasis. Encouragingly, target analysis suggested that HAS patients might potentially benefit from anti-ERBB2 or anti-PD-1 therapy. Taken together, this study systematically demonstrated a high risk of liver metastasis and poor prognosis in HAS, provided a clinicogenomic landscape underlying these unfavorable clinical features, and identified potential therapeutic targets, laying the foundations for developing precise diagnosis and therapy in this rare but lethal disease.

Comprehensive Analysis of Genomic Alterations in Hepatoid Adenocarcinoma of the Stomach and Identification of Clinically Actionable Alterations

Simple Summary

Hepatoid adenocarcinoma of the stomach (HAS) is a subset of gastric cancer (GC) histologically characterized by hepatocellular carcinoma-like foci with or without alpha-fetoprotein secretion, which is easily misdiagnosed. Genomic alterations and potential targets for this population are still largely unknown. Additionally, treatment regimens of HAS are mainly based on GC guidelines, which is not reasonable for diseases with great heterogeneity. The present study comprehensively depicts the genomic features of HAS, and they are significantly different from GC, AFP-producing GC (AFPGC), and liver hepatocellular carcinoma (LIHC). Multiple aggressive behavior-related amplificated or deleted regions in HAS are firstly reported. Moreover, reliable and practicable clinically actionable alterations for HAS are identified, providing evidence for making personalized therapy based on the genomic characteristics of HAS instead of GC.

Abstract

Hepatoid adenocarcinoma of the stomach (HAS) is a rare malignancy with aggressive biological behavior. This study aimed to compare the genetic landscape of HAS with liver hepatocellular carcinoma (LIHC), gastric cancer (GC), and AFP-producing GC (AFPGC) and identify clinically actionable alterations. Thirty-eight cases of HAS were collected for whole-exome sequencing. Significantly mutated genes were identified. TP53 was the most frequently mutated gene (66%). Hypoxia, TNF-α/NFκB, mitotic spindle assembly, DNA repair, and p53 signaling pathways mutated frequently. Mutagenesis mechanisms in HAS were associated with spontaneous or enzymatic deamination of 5-methylcytosine to thymine and defective homologous recombination-related DNA damage repair. However, LIHC was characteristic of exposure to aflatoxin and aristolochic acid. The copy number variants (CNVs) in HAS was significantly different compared to LIHC, GC, and AFPGC. Aggressive behavior-related CNVs were identified, including local vascular invasion, advanced stages, and adverse prognosis. In 55.26% of HAS patients there existed at least one clinically actionable alteration, including ERBB2, FGFR1, CDK4, EGFR, MET, and MDM2 amplifications and BRCA1/2 mutations. MDM2 amplification with functional TP53 was detected in 5% of HAS patients, which was proved sensitive to MDM2 inhibitors. A total of 10.53% of HAS patients harbored TMB > 10 muts/Mb. These findings improve our understanding of the genomic features of HAS and provide potential therapeutic targets.

Discovering Immune-Mediated Mechanisms of Gastric Carcinogenesis Through Single-Cell RNA Sequencing

Single-cell RNA sequencing (scRNAseq) technology is still relatively new in the field of gastric cancer immunology but gaining significant traction. This technology now provides unprecedented insights into the intratumoral and intertumoral heterogeneities at the immunological, cellular, and molecular levels. Within the last few years, a volume of publications reported the usefulness of scRNAseq technology in identifying thus far elusive immunological mechanisms that may promote and impede gastric cancer development. These studies analyzed datasets generated from primary human gastric cancer tissues, metastatic ascites fluid from gastric cancer patients, and laboratory-generated data from in vitro and in vivo models of gastric diseases. In this review, we overview the exciting findings from scRNAseq datasets that uncovered the role of critical immune cells, including T cells, B cells, myeloid cells, mast cells, ILC2s, and other inflammatory stromal cells, like fibroblasts and endothelial cells. In addition, we also provide a synopsis of the initial scRNAseq findings on the interesting epithelial cell responses to inflammation. In summary, these new studies have implicated roles for T and B cells and subsets like NKT cells in tumor development and progression. The current studies identified diverse subsets of macrophages and mast cells in the tumor microenvironment, however, additional studies to determine their roles in promoting cancer growth are needed. Some groups specifically focus on the less prevalent ILC2 cell type that may contribute to early cancer development. ScRNAseq analysis also reveals that stromal cells, e.g., fibroblasts and endothelial cells, regulate inflammation and promote metastasis, making them key targets for future investigations. While evaluating the outcomes, we also highlight the gaps in the current findings and provide an assessment of what this technology holds for gastric cancer research in the coming years. With scRNAseq technology expanding rapidly, we stress the need for periodic review of the findings and assess the available scRNAseq analytical tools to guide future work on immunological mechanisms of gastric carcinogenesis.  

NF-κB-Related Metabolic Gene Signature Predicts the Prognosis and Immunotherapy Response in Gastric Cancer

Background

Sufficient evidence indicated the crucial role of NF-κB family played in gastric cancer (GC). The novel discovery that NF-κB could regulate cancer metabolism and immune evasion greatly increased its attraction in cancer research. However, the correlation among NF-κB, metabolism, and cancer immunity in GC still requires further improvement.

Methods

TCGA, hTFtarget, and MSigDB databases were employed to identify NF-κB-related metabolic genes (NFMGs). Based on NFMGs, we used consensus clustering to divide GC patients into two subtypes. GSVA was employed to analyze the enriched pathway. ESTIMATE, CIBERSORT, ssGSEA, and MCPcounter algorithms were applied to evaluate immune infiltration in GC. The tumor immune dysfunction and exclusion (TIDE) algorithm was used to predict patients' response to immunotherapy. We also established a NFMG-related risk score by using the LASSO regression model and assessed its efficacy in TCGA and GSE62254 datasets.

Results

We used 27 NFMGs to conduct an unsupervised clustering on GC samples and classified them into two clusters. Cluster 1 was characterized by high active metabolism, tumor mutant burden, and microsatellite instability, while cluster 2 was featured with high immune infiltration. Compared to cluster 2, cluster 1 had a better prognosis and higher response to immunotherapy. In addition, we constructed a 12-NFMG (ADCY3, AHCY, CHDH, GUCY1A2, ITPA, MTHFD2, NRP1, POLA1, POLR1A, POLR3A, POLR3K, and SRM) risk score. Followed analysis indicated that this risk score acted as an effectively prognostic factor in GC.

Conclusion

Our data suggested that GC subtypes classified by NFMGs may effectively guide prognosis and immunotherapy. Further study of these NFMGs will deepen our understanding of NF-κB-mediated cancer metabolism and immunity.