Gastric signet ring cell carcinoma (GSRCC) possesses unique epidemiology and pathogenesis in the field of cancer, but its incidence is low. Unfortunately, there is currently a lack of systematic research focusing on the prognostic proteomic features of GSRCC. Given this knowledge gap, this study aims to comprehensively characterize the proteomic landscape of GSRCC using a reliable and reproducible DIA-PCT method. This study objectives include characterizing the heterogeneity of GSRCC, performing molecular typing, identifying potential biomarkers and therapeutic targets, and providing a resource for stratified analysis of GSRCC. To achieve these goals, the investigators selected a cohort of 112 GSRCC patients from a pool of over 10,000 gastric cancer patients and conducted a proteomic analysis using the DIA-PCT method. This meticulous approach revealed four novel proteomic subtypes of GSRCC, each exhibiting unique molecular characteristics. Additionally, the investigators discovered that PRDX2 and DDX27 can serve as predictive biomarkers for GSRCC, which were further validated in an independent cohort of 75 GSRCC patients. Furthermore, the investigators paid particular attention to the MLT-GSRCC subgroup and identified three distinct proteomic clusters among MLT-GSRCC patients. Subtype 2 within this subgroup demonstrated the poorest prognosis. Through a rigorous screening process, the investigators determined potential targets for the treatment of GSRCC. In conclusion, these findings contribute to the investigators understanding of the heterogeneity of GSRCC and provide valuable resources for future clinical stratification and targeted treatment strategies.

Inclusion Criteria:

• confirmed GSRCC by pathology, where GSRCC is defined as having a percentage of signet ring cell ≥ 50%
• patients with complete medical information
• patients with survival follow-up information

Exclusion Criteria:

• patients with other malignant tumors
• presence of other pathological components (e.g., neuroendocrine carcinoma and squamous cell carcinoma, etc)
• incomplete or lost case information

These cases had a signet ring cell content greater than 70% and had not undergone prior chemotherapy or radiotherapy

This study does not involve drug clinical trials but focuses on ensuring the confidentiality of patient information. To protect patient privacy, a coding system was used instead of real names when entering patient information such as names and ages. Each patient was assigned a study identification number upon enrollment. Throughout the entire study, only the main researchers in the research team have the authority to access the true personal data of patients obtained from the electronic database (such as names and ages), and it is strictly prohibited to circulate or share this information. During the publication of the research article, the main researchers in the research team will use sample coding to replace patient privacy information (such as names) to achieve de-identification. Additionally, the protection of personal information for study participants must be maintained throughout the entire research process, and it is strictly forbidden to circulate or leak such information.