Surgical Resection First for Localized Gastric Adenocarcinoma: Are There Adjuvant Options?

miR-939, as an important regulator in various cancers pathogenesis, has diagnostic, prognostic, and therapeutic values: a review

BACKGROUND

MicroRNAs (miRNAs or miRs) are highly conserved non-coding RNAs with a short length (18-24 nucleotides) that directly bind to a complementary sequence within 3'-untranslated regions of their target mRNAs and regulate gene expression, post-transcriptionally. They play crucial roles in diverse biological processes, including cell proliferation, apoptosis, and differentiation. In the context of cancer, miRNAs are key regulators of growth, angiogenesis, metastasis, and drug resistance.

MAIN BODY

This review primarily focuses on miR-939 and its expanding roles and target genes in cancer pathogenesis. It compiles findings from various investigations. MiRNAs, due to their dysregulated expression in tumor environments, hold potential as cancer biomarkers. Several studies have highlighted the dysregulation of miR-939 expression in human cancers.

CONCLUSION

Our study highlights the potential of miR-939 as a valuable target in cancer diagnosis, prognosis, and treatment. The aberrant expression of miR-939, along with other miRNAs, underscores their significance in advancing our understanding of cancer biology and their promise in personalized cancer care.

Preoperatively Treated Diffuse-Type Gastric Adenocarcinoma: Glucose vs. Other Energy Sources Substantially Influence Prognosis and Therapy Response

Simple Summary

The diffuse type of gastric adenocarcinoma (dGAC) generally confers a poor prognosis compared to intestinal type. Some dGACs are not avid on fluorine-18 fluoro-2-deoxy-D-glucose PET (FDG-PET) while others seem to consume glucose avidly. We analyzed the outcomes based on the avidity of the primary on baseline FDG-PET. Our data suggest that if dGACs used glucose as an energy source then the prognosis was very poor while non-glucose sources improved prognosis. Multi-platform (including metabolomics) profiling of dGACs would yield useful biologic understanding.

Abstract

Diffuse type of gastric adenocarcinoma (dGAC) generally confers a poor prognosis compared to intestinal type. Some dGACs are not avid on fluorine-18 fluoro-2-deoxy-D-glucose PET (FDG-PET) while others seem to consume glucose avidly. We analyzed the outcomes based on the avidity (high with standardized uptake value (SUV) > 3.5 or low with SUV ≤ 3.5) of the primary on baseline FDG-PET. We retrospectively selected 111 localized dGAC patients who had baseline FDG-PET (all were treated with preoperative chemotherapy and chemoradiation). FDG-PET avidity was compared with overall survival (OS) and response to therapy. The mean age was 59.4 years and with many females (47.7%). The high-SUV group (58 (52.3%) patients) and the low-SUV group (53 (47.7%) patients) were equally divided. While the median OS for all patients was 49.5 months (95% CI: 38.5–98.8 months), it was 98.0 months (95% CI: 49.5–NE months) for the low-SUV group and 36.0 months for the high-SUV (p = 0.003). While the median DFS for all patients was 38.2 months (95% CI: 27.7–97.6 months), it was 98.0 (95% CI: 36.9–NE months) months for the low-SUV group was and only 27.0 months (95% CI: 15.2–63.2 months) for the high-SUV group (p = 0.005). Clinical responses before surgery were more common in the low-SUV group but overall we observed only 4 pathologic complete responses in 111 patients. Our unique data suggest that if dGACs used glucose as an energy source then the prognosis was very poor while non-glucose sources improved prognosis. Multi-platform (including metabolomics) profiling of dGACs would yield useful biologic understanding.

Low metabolic activity in primary gastric adenocarcinoma is associated with resistance to chemoradiation and the presence of signet ring cells

PURPOSES

Preoperative chemoradiation is a potential treatment option for localized gastric adenocarcinoma (GAC). Currently, the response to chemoradiation cannot be predicted. We analyzed the pretreatment maximum standardized uptake value (SUV_max) and total lesion glycolysis (TLG) on positron emission tomography/computed tomography as potential predictors of the response to chemoradiation.

METHODS

We analyzed the SUV_max and TLG data from 59 GAC patients who received preoperative chemoradiation. We used logistic regression models to predict a pathologic complete response (pCR) and Kaplan-Meier curves to determine overall survival among patients with high and low SUV_max or TLG.

RESULTS

Twenty-nine patients (49%) had Siewert type III adenocarcinoma and 30 (51%) had tumors located in the lower stomach. Forty-one patients had poorly differentiated GAC, and 26 had signet ring cells. The median SUV_max was 7.3 (0-28.2) and the median TLG was 56.6 (0-1881.5). Patients with signet ring cells had a low pCR rate, as well as a low SUV_max and TLG. In the multivariable logistic regression model, high SUV_max was a predictor of pCR (odds ratio = 11.1, 95% confidence interval = 2.12-50.0, p = 0.004). Overall survival was not associated with the SUV_max (log-rank p = 0.69) or TLG (log-rank p = 0.85) CONCLUSION: A high SUV_max was associated with sensitivity to chemoradiation and pCR in GAC, and signet ring cells seemed to confer resistance.

DNA methylation genome-wide analysis in remnant and primary gastric cancers

BACKGROUND

Although primary (PGC) and remnant gastric cancers (RGC) both originate from the same gastrointestinal organ, they have very distinct clinicopathological behaviors. We hypothesized that there would be distinct differences in DNA methylation patterns that would occur during carcinogenesis of RGC and PGC, and that the differences in methylation patterns may help identify the primary factor contributing to chronic inflammation in patients with RGC.

METHODS

We investigated the genome-wide DNA methylation patterns of PGC and RGC tissues from 48 patients using the Infinium HumanMethylation450 Beadchip assay. The results were validated by quantitative methylation-specific PCR (qMSP) in separate, independent cohorts.

RESULTS

We found that in our training cohort of 48 patients, the most variable genes from the gastric cancer tissues identified by the Infinium HumanMethylation450 Beadchip clustered the resultant heatmap into high and low methylation groups. On multivariate analysis, PGCs contributed significantly to the high methylation group (p = 0.004, OR 12.33), which suggested that the promoter methylation status in PGC is higher than that in RGC. Supporting this conclusion was the finding that in a separate qMSP analysis in a test cohort, the EPB41L3 gene, chosen because of its high β value on microarray analysis in the gastric cancer tissues, had significantly higher DNA promoter methylation in cancer tissues in the validation PGC tissues than in RGC.

CONCLUSIONS

This study demonstrated that promoter methylation status in PGC is higher than in RGC. This result may reflect the effects of the absence of Helicobacter pylori on the reduced DNA methylation in the remnant stomach.

Two postoperative chemotherapies for gastric cancer: FOLFOX4 vs. TPF

Clinical effects of FOLFOX4 and TPF chemotherapy regimen on postoperative gastric cancer patients were investigated. A total of 60 patients admitted to the First People's Hospital of Changzhou receiving gastric cancer operation were selected and they were divided into two groups at random. Thirty patients in the FOLFOX4 group were treated with oxaliplatin, fluorouracil and leucovorin, while 30 patients in the TPF group were treated with paclitaxel, fluorouracil and cisplatin. The therapeutic effects, adverse reactions, quality of life and survival time of patients in the two groups were observed. The total effective rate of the FOLFOX4 group was 73.3%, which was significantly higher than that of the TPF group (43.3%), and the difference was statistically significant (P<0.05). The proportions of neurotoxicity and thrombocytopenia in the FOLFOX4 group were 56.7 and 33.3%, while those in the TPF group were 26.7 and 60%, respectively, and the differences were statistically significant (P<0.05). The increasing proportion of postoperative scores of the FOLFOX4 group was 46.7%, which was significantly higher than that of the TPF group (20%), and the difference was statistically significant (P<0.05). The 2- and 3-year survival rates of the FOLFOX4 group were 63.3 and 50%, which were significantly higher than those of the TPF group (36.7 and 23.3%), and the differences were statistically significant (P<0.05). Therefore, the effective rate of FOLFOX4 regimen is high in the treatment of gastric cancer with relatively fewer adverse reactions, which has a certain advantage.

Recent trend in gastric cancer treatment in the USA

Gastric adenocarcinoma (GAC) is estimated as the fifteenth most common cancer in the USA. Incidence rate has been gradually decreasing, but prognosis remains dismal. For patients with locally advanced GAC (stage > T1B and < T4B), multimodality therapies, such as surgery, chemotherapy, and radiation therapy, are needed. Perioperative chemotherapy or postoperative chemoradiation/chemotherapy is recommended. For metastatic GAC patients, combination of two cytotoxics (platinum compound and fluoropyrimidine) has become a common place in the USA, and when HER2 is positive, trastuzumab is added. When GAC progresses after the first line therapy, additional biomarkers (microsatellite instability and programmed death ligand 1) should be tested so that checkpoint inhibitors can be used. Overall, the options for advanced GAC patients are limited and more research is needed.

Patterns of relapse in patients with localized gastric adenocarcinoma who had surgery with or without adjunctive therapy: costs and effectiveness of surveillance

PURPOSE

After therapy of localized gastric adenocarcinoma (GAC) patients, the costs of surveillance, relapse patterns, and possibility of salvage are unknown.

MATERIALS AND METHODS

We identified 246 patients, who after having a negative peritoneal staging, received therapy (any therapy which included surgery) and were surveyed (every 3-6 months in the first 3 years, then yearly; ∼10 CTs and ∼7 endoscopies per patient). We used the 2016 Medicare dollars reimbursed as the "costs" for surveillance.

RESULTS

Common features were: Caucasians (57%), men (60%), poorly differentiated histology (76%), preoperative chemotherapy (74%), preoperative chemoradiation (59%), and had surgery (100%). At a median follow-up of 3.7 years (range, 0.1 to 18.3), the median overall survival (OS) was 9.2 years (95% CI, 6.0 to 11.2). Tumor grade (p = 0.02), p/yp stage (p < 0.001), % residual GAC (p = 0.05), the R status (p = 0.01), total gastrectomy (p = 0.001), and relapse type (p = 0.02) were associated with OS. Relapse occurred in 79 (32%) patients (only 8% were local-regional) and 90% occurred within 36 months of surgery. P/yp stage (p < 0.001) and total gastrectomy (p = 0.01) were independent prognosticators for OS in the multivariate analysis. Only 1 relapsed patient had successful salvage therapy. The estimated reimbursement for imaging studies and endoscopies was $1,761,221.91 (marked underestimation of actual costs).

CONCLUSIONS

The median OS of localized GAC patients was excellent with infrequent local-regional relapses. Rigorous surveillance had a low yield and high "costs". Our data suggest that less frequent surveillance intervals and limiting expensive investigations to symptomatic patients may be warranted.

Advanced gastric adenocarcinoma: optimizing therapy options

INTRODUCTION

Gastric adenocarcinoma (GAC) is the fifth most common cancer and third leading cause of cancer related mortality worldwide. When localized, cure is achievable with surgery and adjunctive therapies in some patients, however, once advanced, GAC is not a curable condition. Only two targeted agents (trastuzumab and ramucirumab) have been approved and apatinib was approved only in China. Because of the heterogeneous nature of GAC, it is not possible to assess a standard therapeutic approach. Areas covered: In this review, we aimed to describe the optimal systemic therapy regimens for advanced GAC. A literature search was performed to identify all phase II-III studies about advanced GAC from PubMed, clinicaltrials.gov, American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO) websites. Expert commentary: A combination of a platinum compound and a fluoropyrimidine is ideal as first line therapy. Trastuzumab should be added if the tumor is HER2 positive. In the second line setting, paclitaxel/ramucirumab is preferred over ramucirumab alone. Recently, two similar molecular classifications for GAC have been proposed. A better understanding of molecular and immune biology of GAC could identify new therapeutic targets.

Decreased expression of miR-939 contributes to chemoresistance and metastasis of gastric cancer via dysregulation of SLC34A2 and Raf/MEK/ERK pathway

BACKGROUND

The development of chemoresistance and metastasis are the leading causes of death for gastric cancer (GC) patients, however, the molecular mechanisms involved remain unclear. Dysregulation of miRNAs is associated with a variety of disease, including GC. Recently, microarray profiling analysis revealed that miR-939 was dysregulated in human GC samples, but the role of miR-939 in GC has not been intensively investigated.

METHODS

In the present study, we firstly examined the expression pattern of miR-939 in two independent cohorts of clinical GC samples: one cohort of 112 GC patients with stage I-III disease who underwent surgery followed by adjuvant chemotherapy; and another cohort of 110 GC patients with stage IV disease who received palliative chemotherapy. A series of in vivo and in vitro assays were then performed to investigate the function of miR-939 in GC.

RESULTS

We detected that reduced expression of miR-939 was associated with chemoresistance and increased risk of tumor recurrence in GC patients. Further function study demonstrated that overexpression of miR-939 suppressed GC cell growth, and enhanced 5-fluorouracil-induced chemosensitivity by compromising cellular growth and inducing apoptosis in vitro and in vivo. Moreover, miR-939 repressed the migration and invasion of GC cells in vitro, and diminished the occurrence of lung metastasis in vivo. We further identified solute carrier family 34 member 2 (SLC34A2) was a novel target of miR-939. Mechanistically, we elucidated that miR-939 exerted its function mainly through inhibiting SLC34A2/Raf/MEK/ERK pathway, which is activated in GC. Multivariate analysis identified miR-939, SLC34A2, and their combination as independent indicators for poor prognosis and tumor recurrence in GC patients.

CONCLUSION

Our data indicate that miR-939 acts as a tumor suppressor miRNA in GC, and miR-939/SLC34A2 axis represents a novel therapeutic strategy for future GC treatment.

Potentially Curable Cancers of the Esophagus and Stomach

Gastric and gastroesophageal adenocarcinomas continue to be a major health burden globally and collectively represent the third leading cause of cancer death. Among patients with metastatic disease, most die of their cancer because of the limited number of modestly effective treatment regimens available today. The progress against these cancers has been slow compared with many other solid tumors despite many attempts. In-depth molecular profiling has also not been completed. Even when these cancers are localized, they impose considerable challenges for the patient, relatives, and treatment team alike. Localized gastric or gastroesophageal cancer is best managed with a multidisciplinary approach. This review focuses on the management of localized cancers by reviewing the current literature and explaining certain principles that help guide therapy for these patients. The future, however, will afford numerous opportunities, including exploitation of initial data from The Cancer Genome Atlas, to identify novel targets and drugs, harness the prowess of the immune system, and customize therapy for each patient.