Characteristics and prognosis of mucinous gastric carcinoma

Cd44v6 acts as a directional responding factor in the process of transcoelomic metastasis from gastric carcinoma to Krukenberg tumor

INTRODUCTION

Due to the limited number of studies focusing on the optimal treatment of multiple Krukenberg tumor (KT)-gastric carcinoma (KT - GC), it is necessary to conduct large-scale studies to confirm the definite role of serum tumor markers in the diagnosis and prognosis of KT. Moreover, the clinical significance of variant 6 of CD44 (CD44v6) in transcoelomic metastasis should be considered.

AREAS COVERED

This review covers molecular pre-cancer diagnosis, gastric carcinoma metastasis, and anti-cancer treatments. Additionally, gastrointestinal cancer metastasis is a key area for improvement.

EXPERT OPINION

The detection of CD44v6 differs in the World Health Organization Classification of Gastric Adenocarcinoma, the Lauren Classification of Gastric Adenocarcinoma, and the anatomic location of gastric adenocarcinoma. The results were compared among the three groups. The mechanism of gastric adenocarcinoma metastasis still requires further elucidation. CD44v6 molecular detection helps clarify the pre-cancer diagnosis of KT before seeding. If subsequent studies confirm its role as a signaling molecule, it could pave the way for new research directions in clinical practice; however, additional academic confirmation is necessary.

Clinicopathologic and genomic characteristics of mucinous gastric adenocarcinoma

BACKGROUND

Mucinous gastric adenocarcinoma (MGC) is a rare but distinctive histologic subtype of gastric cancer (GC). The clinico-pathologic and genomic characteristics of MGC have not been well evaluated.

METHODS

We collected individual data from five cohorts targeting the microsatellite instability (MSI) of GC (n = 5089) to evaluate the clinico-pathologic characteristics of MGC. In addition, public genomic databases were used for genomic analysis. The characteristics of MGC were compared with those of non-mucinous GC (NMGC).

RESULTS

MGC (n = 158, 3.1%) showed distinctive characteristics in terms of age, sex, and TNM stage compared to NMGC (n = 4931). MGC was frequently associated with MSI-high (OR: 2.24, 95% confidence interval [CI] 1.44-3.40, p < 0.001), while mutually exclusive to the Epstein-Barr virus type. The prognosis of MGC was better than that of NMGC (adj.HR: 0.731, 95% CI 0.556-0.962, p = 0.025). There was no clear benefit from postoperative chemotherapy in MGC. TP53 was the main driver mutation in the MGC without recurrent variants. MGC was related to high expression of GPR120 and B3GNT6 and moderate regulation of epithelial-mesenchymal transition (EMT)-up signature with a high EMT-down signature, and those characteristics was related to favorable prognosis of GC (log-rank p = 0.044, p < 0.001, p < 0.001, respectively). MSI-H of MGC was associated with low cancer-associate fibroblasts but high CD274 (PD-L1) expression compared to microsatellite stable MGC, suggesting that immune checkpoint inhibitors may be useful for the MSI-H of MGC.

CONCLUSION

MGC could be a surrogate for performing MSI but not the EBV test in GC. Further, its genetic characteristics lead to a favorable prognosis for MGC.

Neoadjuvant chemotherapy improves survival in patients with oesophageal mucinous adenocarcinoma: Post-hoc analysis of the UK MRC OE02 and OE05 trials

BACKGROUND

Adenocarcinoma with more than 50% extracellular mucin is a relatively rare histological subtype of gastrointestinal adenocarcinomas. The clinical impact of extracellular mucin in oesophageal adenocarcinoma (OeAC) has not been investigated in detail. We hypothesised that patients with mucinous OeAC (OeAC_mucin) do not benefit from neoadjuvant chemotherapy.

METHODS

OeAC patients either treated by surgery alone in the OE02 trial (S-patients) or by neoadjuvant chemotherapy followed by surgery (CS-patients) in OE02 or OE05 trials were included. Cancers from 1055 resection specimens (OE02 [test cohort]: 187 CS, 185 S; OE05 [validation cohort]: 683 CS) were classified as either mucinous (more than 50% of the tumour area consists of extracellular mucin, OeAC_mucin) or non-mucinous adenocarcinoma (OeAC_non-mucin). The relationship between histological phenotype, clinicopathological characteristics, survival and treatment was analysed.

RESULTS

Overall, 7.3% and 9.6% OeAC were classified as OeAC_mucin in OE02 and OE05, respectively. In OE02, the frequency of OeAC_mucin was similar in S and CS-patients. Patients with OeAC_mucin treated with surgery alone had a poorer overall survival compared with OeAC_non-mucin patients (hazard ratio: 2.222, 95% confidence interval: 1.08-4.56, P = 0.025). Patients with OeAC_mucin treated with neoadjuvant chemotherapy and surgery had similar survival as OeAC_non-mucin patients in test and validation cohort.

CONCLUSIONS

This is the first study to suggest in a post-hoc analysis of material from two independent phase III clinical trials that the poor survival of patients with mucinous OeAC can be improved by neoadjuvant chemotherapy. Future studies are warranted to identify potential underlying biological, biochemical or pharmacokinetic interactions between extracellular mucin and chemotherapy.

A survival comparison of gastric mucin-producing adenocarcinoma to conventional adenocarcinoma: a SEER database analysis

Background

Compared to conventional adenocarcinoma (CA), mucin-producing adenocarcinoma (MPA) is an uncommon histological subtype and is usually separated from other histological types and has been evaluated separately. The objective was to compare the clinicopathological characteristics and survivals of MPA with CA.

Methods

We retrospectively analyzed 1515 MPA patients in SEER database. Log-rank tests and KM survival curves were applied to determine the differences in overall survival (OS) and cancer specific survival (CSS) time.

Results

No significant differences were noted in OS and CSS time. The MPA patients who were treated with surgery and chemotherapy exhibited longer OS and CSS time periods than those without treatment. MPA patients treated with radiotherapy exhibited similar OS and CSS time with those without radiotherapy. MPA was not a prognostic factor of survival.

Conclusions

MPA was a rare histological type of gastric cancer. Patients with MPA exhibited similar prognosis with those with CA. Surgery and chemotherapy were effective treatments for patients with MPA.

Deep Learning for Automatic Subclassification of Gastric Carcinoma Using Whole-Slide Histopathology Images

Histomorphologic types of gastric cancer (GC) have significant prognostic values that should be considered during treatment planning. Because the thorough quantitative review of a tissue slide is a laborious task for pathologists, deep learning (DL) can be a useful tool to support pathologic workflow. In the present study, a fully automated approach was applied to distinguish differentiated/undifferentiated and non-mucinous/mucinous tumor types in GC tissue whole-slide images from The Cancer Genome Atlas (TCGA) stomach adenocarcinoma dataset (TCGA-STAD). By classifying small patches of tissue images into differentiated/undifferentiated and non-mucinous/mucinous tumor tissues, the relative proportion of GC tissue subtypes can be easily quantified. Furthermore, the distribution of different tissue subtypes can be clearly visualized. The patch-level areas under the curves for the receiver operating characteristic curves for the differentiated/undifferentiated and non-mucinous/mucinous classifiers were 0.932 and 0.979, respectively. We also validated the classifiers on our own GC datasets and confirmed that the generalizability of the classifiers is excellent. The results indicate that the DL-based tissue classifier could be a useful tool for the quantitative analysis of cancer tissue slides. By combining DL-based classifiers for various molecular and morphologic variations in tissue slides, the heterogeneity of tumor tissues can be unveiled more efficiently.

Clinical Outcomes of Mucinous Gastric Carcinomas Compared with Non-mucinous and Signet Ring Cell Carcinomas

Background/Aims

This study examined the clinical features and prognosis of patients with mucinous gastric carcinoma (MGC), non-mucinous gastric carcinoma (NMGC), and signet ring cell gastric carcinoma (SRC).

Methods

A retrospective cohort study was performed, enrolling 65 patients with MGC from January 2007 to December 2016. During the same period, 1,814 patients with histologically proven gastric cancers underwent curative or palliative operations. One hundred and ninety-five NMGC patients were selected as the 1:3 age- and sex-matched control groups. In addition, 200 SRC patients were identified. This study evaluated the demographic features of the patients, pathologic features of the tumor, and the predictive factors, such as the recurrence-free survival and overall survival.

Results

The recurrence rates were significantly high in MGC than in NMGC or SRC (both p<0.01). The proportion of early gastric cancer was lower in the MGC group than in the other groups (p<0.01). In addition, metastatic lymph nodes were found more frequently in the MGC group (p<0.01), and the proportion of initial pT4, M1 stage, was highest in the MGC group. The recurrence-free survival and overall survival in the MGC group were significantly lower than those in the NMGC or SRC. Subgroup analysis showed that patients with the same American Joint Committee on Cancer (AJCC) stage of each cancer group showed a similar prognosis.

Conclusions

MGC frequently presents an advanced stage with an unfavorable prognosis compared to NMGC or SRC. On the other hand, MGC of the same AJCC stage had a similar prognosis to NMGC and SRC.

Prognostic analysis of gastric signet ring cell carcinoma and mucinous carcinoma: a propensity score-matched study and competing risk analysis

Background: Limited evidence and contradictory results have been reported regarding the impact of signet ring cell carcinoma (SRC) and mucinous gastric cancer (MGC) classifications on the prognosis of gastric cancer (GC).

Results: Information on 6017 patients and 266 patients was extracted from the SEER database and our hospital records, respectively. We found that patients with MGC had a better survival rate than those with SRC (P=0.012), but in the early stage, MGC was a risk factor for a poor prognosis. After PSM, for both patients from the SEER database and our hospital, the prognosis of patients with SRC was poorer than that of patients with MGC (P<0.05), but patients with MGC in early-stage GC showed poorer survival. Additionally, SRC was demonstrated to be a risk factor in the multivariate competing risk regression model for cancer-specific survival.

Conclusion: Patients with SRC may have a worse prognosis than those with MGC, but for early-stage GC, patients with SRC have a better prognosis than those with MGC.

Method: Patients from the SEER database and from our hospital diagnosed with SRC or MGC were included in a Cox regression analysis, multivariate competing risk model and propensity score matching (PSM) analysis.

Diffuse-type Gastric Mucinous and Signet Ring Cell Adenocarcinoma in a Captive California King Snake (Lampropeltis getula californiae)

An adult female California king snake (Lampropeltis getula californiae) housed in Taipei Zoo was presented with a 2-week history of anorexia, fatigue and abdominal swelling. Exploratory laparotomy revealed a gastric mass with two circular perforations and multiple mottled white to beige protuberances along the mucosal surface. Histologically, the gastric mass showed an invasive, transmural growth of epithelial cells arranged in nests, lobules, acini and sheets in the mucosa and submucosa that progressively transformed into signet ring cells in the muscularis externa and subserosa. All of the neoplastic cells expressed pan-cytokeratin immunohistochemically. Based on the World Health Organization histological criteria, a diagnosis of diffuse-type gastric mucinous and signet ring cell adenocarcinoma was made.

Prognostic significance of mucinous component in gastric adenocarcinoma after radical D2 gastrectomy

BACKGROUND

The mucinous component is a special histologic factor in gastric adenocarcinoma. The aim of this study was to assess the prognostic significance of mucinous component in gastric adenocarcinoma according to proportion.

PATIENTS AND METHODS

Candidate patients with gastric adenocarcinoma were given radical D2 gastrectomies from September 2008 to May 2015 in our division. Clinicopathologic data and prognosis were monitored and analyzed among gastric adenocarcinoma patients with various proportions of mucinous component.

RESULTS

A total of 690 gastric adenocarcinomas with various proportions of mucinous component from 6,025 gastric adenocarcinoma patients were included. Higher numbers of patients with mucinous component came from: young patients, females, those with drinking history, at lower locations, Borrmann type III and IV, T4 stage, and positive for dissected lymph nodes. Tumors and pathological molecular markers showed more positivity in CEA, CA19-9, S100, and CD34. As the various proportions increased, more mucinous component seemed to be accompanied by more Borrmann type III and IV, T4 stage, and more positive expression of CEA and CA19-9. However, no significant difference in 5-year overall survival rate was observed among various proportions or existence of mucinous component. Also, proportion or existence of mucinous component was not an independent prognostic factor in multivariate analysis.

CONCLUSION

Mucinous component was not a prognostic factor for gastric adenocarcinoma after radical D2 gastrectomy, no matter what proportion the component comprised. However, gastric adenocarcinoma with mucinous component showed specific clinicopathological characteristics, such as more advanced tumor stage, different age and sex, and more positive rate of molecular markers, which might provide a new strategy for optimal individual diagnosis and therapies.

Prognostic Impact of Different Histological Types on Gastric Adenocarcinoma: a Surveillance, Epidemiology, and End Results Database Analysis

The clinicopathological characteristics and prognosis of gastric mucinous adenocarcinoma (MAC) and signet ring cell carcinoma (SRC) are still controversial. We designed our study to evaluate the clinicopathologic features and prognosis of MAC, SRC and ordinary gastric adenocarcinoma (OGAC) by analyzing the Surveillance, Epidemiology, and End Results (SEER)-registered database. The 5-year overall survival (OS) of patients with SRC was significantly lower than that of patients with MAC (P = 0.001) and OGAC (P < 0.001), and there was no significant difference in 5-year OS between MAC and OGAC (P = 0.804). Furthermore, there were no significant differences of 5-years OS among these three groups at stage I, II and III (all P > 0.05) and no significant difference between MAC and OGAC at stage IV (P = 0.110). Patients in SRC group had significantly worse survival than those in MAC and OGAC at stage IV (both P = 0.008), with 5-year OS of 3.3%, 5.8%, and 5.8%, respectively. However, the histological type was not found to be an independent prognostic factor of gastric cancer according to the multivariate analysis with Cox regression.

Comparison of clinicopathological and prognostic characteristics in patients with mucinous carcinoma and signet ring cell carcinoma of the stomach

AIM

To determine whether there are any clinicopathological or prognostic differences between mucinous gastric carcinoma (MGC) and signet ring cell carcinoma (SRCC).

METHODS

Pathological parameters, clinical parameters, and treatment efficacy were compared in patients with MGC and SRCC.

RESULTS

In total, 193 patients (51 with MGC and 142 with SRCC) were included in this study. Patients with SRCC in particular had notably higher lymphovascular invasion, perineural invasion, rate of Borrmann types III and IV, and stage III-IV cancer (according to its TNM stage) compared with patients with MGC. However, tumor size was larger in patients with MGC (tumor size ≥5 cm). Median overall survival (OS) was 29.8 months in the MGC group and 16.6 months in the SRCC group (p = .04). The median OS in stage I-III patients was 59.9 and 42.5 months in the MGC and SRCC groups, respectively (p = .35). Comparing OS between MGC and SRCC stage IV patients revealed that the median OS was 10.1 and 8.8 months, respectively (p = .96). Multivariate analysis of the entire patient group revealed that the presence of weight loss at diagnosis, distant metastasis, and lymph node involvement were significantly related to OS. Multivariate analysis also revealed that weight loss at the diagnosis and T3-4 tumors were significant factors influencing OS in the stage I-III group.

CONCLUSIONS

Patients with SRCC had generally poorer prognosis and lower survival rates compared with patients with MGC. Further studies on the prognosis and treatment plan based on the pathological subtypes of SRCC and MGC are still needed.

Reduced expression of the long non-coding RNA AI364715 in gastric cancer and its clinical significance

Long non-coding RNA (lncRNA), which is greater than 200 nucleotides, is a class of RNA molecules without protein coding function. In recent years, studies have shown that lncRNAs are associated with cancers. They are affecting the occurrence and development of cancers. However, the diagnostic significances of lncRNAs in gastric cancer are largely unknown. In this study, we focused on AI364715, one typical lncRNA. A total of 186 samples were collected from two cancer centers. To find the potential association between its level and gastric cancer, we first collected 75 paired gastric cancer tissues and normal tissues, which are 5 cm away from the edge of carcinoma. Besides, 18 human healthy gastric mucosa and 18 gastric precancerous lesions (dysplasia) were also collected. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was first used to detect the expression level of AI364715 at multiple stages of gastric tumorigenesis. Then, the relationships between AI364715 level and the clinicopathological factors of patients with gastric cancer were analyzed. The results showed that the expression level of AI364715 in gastric cancer tissues was downregulated. Meanwhile, its expression level was closely associated with tumor size and differentiation. More importantly, AI364715 expression level was significantly changed in dysplasia, the typical precancerous lesions. Taken together, AI364715 may be a potential biomarker for the diagnosis of gastric cancer.