Mucin expression in gastric- and gastro-oesophageal signet-ring cell cancer: results from a comprehensive literature review and a large cohort study of Caucasian and Asian gastric cancer

Background: The literature on the prognostic relevance of signet-ring cell (SRC) histology in gastric cancer (GC) is controversial which is most likely related to inconsistent SRC classification based on haematoxylin–eosin staining. We hypothesised that mucin stains can consistently identify SRC-GC and predict GC patient outcome. Methods: We performed a comprehensive literature review on mucin stains in SRC-GC and characterised the mucin expression in 851 Caucasian GC and 410 Asian GC using Alcian Blue (AB)-Periodic Acid-Schiff (PAS), MUC2 (intestinal-type mucin), and MUC5AC (gastric-type mucin). The relationship between mucin expression and histological phenotype [poorly cohesive (PC) including proportion of SRCs, non-poorly cohesive (non-PC), or mucinous (MC)], clinicopathological variables, and patient outcome was analysed. Results: Depending on mucin expression and cut-offs, the positivity rates of SRC-GC reported in the literature varied from 6 to 100%. Patients with MUC2 positive SRC-GC or SRC-GC with (gastro)intestinal phenotype had poorest outcome. In our cohort study, PC with ≥ 10% SRCs expressed more frequently MUC2, MUC5AC, and ABPAS (p < 0.001, p = 0.004 and p < 0.001, respectively). Caucasians with AB positive GC or combined ABPAS-MUC2 positive and MUC5AC negative had poorest outcome (all p = 0.002). This association was not seen in Asian patients. Conclusions: This is the first study to suggest that mucin stains do not help to differentiate between SRC-GC and non-SRC-GC. However, mucin stains appear to be able to identify GC patients with different outcome. To our surprise, the relationship between outcome and mucin expression seems to differ between Caucasian and Asian GC patients which warrants further investigations

The yield of diagnostic laparoscopy with peritoneal lavage in gastric adenocarcinoma: A retrospective cohort study

\ua9 2024 The AuthorsIntroduction: Diagnostic laparoscopy (DL) with peritoneal lavage has been adopted as a standard staging procedure for patients with gastric cancer (GC). Evaluation of the value of DL is important given ongoing improvements in diagnostic imaging and treatment. As contemporary data from European centres are sparse, this retrospective cohort study aimed to assess the yield of DL in patients with potentially curable gastric cancer, and to identify predictive factors for peritoneal metastases. Methods: Patients with adenocarcinoma of the stomach, treated between January 2016 and December 2018, were identified from institutional databases of two high volume European Upper-GI centres. Patients who underwent a DL with peritoneal lavage for potentially curable disease after clinical staging with imaging (cT1-4N0-3M0) were included. The primary outcome was the proportion of patients with a positive DL, defined as macroscopic metastatic disease, positive peritoneal cytology washings (PC+) or locally irresectable disease. Results: Some 80 of 327 included patients (24.5%) had a positive DL, excluding these patients from neoadjuvant treatment (66 of 327; 20.2%) and/or surgical resection (76 of 327; 23.2%). In 34 of 327 patients (10.3%), macroscopic metastatic disease was seen, with peritoneal deposits in 30 of these patients. Only 16 of 30 patients with peritoneal disease had positive cytology. Some 41 of 327 patients (12.5%) that underwent DL had PC+ in the absence of macroscopic metastases and five patients (1.5%) had an irresectable primary tumour. Diffuse type carcinoma had the highest risk of peritoneal dissemination, irrespective of cT and cN categories. Conclusion: The diagnostic yield of staging laparoscopy is high, changing the management in approximately one quarter of patients. DL should be considered in patients with diffuse type carcinoma irrespective of cT and cN categories