HLA-A+ tertiary lymphoid structures with reactivated tumor infiltrating lymphocytes are associated with a positive immunotherapy response in esophageal squamous cell carcinoma.

BACKGROUND: Immune checkpoint blockade (ICB) therapy provides remarkable clinical benefits for multiple cancer types. However, the overall response rate to ICB therapy remains low in esophageal squamous cell carcinoma (ESCC). This study aimed to identify biomarkers of ICB therapy for ESCC and interrogate its potential clinical relevance. METHODS: We investigated gene expression in 42 treatment-naïve ESCC tumor tissues and identified differentially expressed genes, tumor-infiltrating lymphocytes and immune-related genes signatures associated with differential immunotherapy responses. We systematically assessed the tumor microenvironment using the NanoString GeoMx digital spatial profiler, single-cell RNA-seq and multiplex immunohistochemistry in ESCC. Finally, we evaluated the associations between HLA-A-positive tertiary lymphoid structures (TLSs) and patients' responses to ICB in 60 ESCC patients. RESULTS: Tumor infiltrating B lymphocytes and several immune-related gene signatures, such as the antigen presenting machinery (APM) signature, are significantly elevated in ICB treatment responders. Multiplex immunohistochemistry identified the presence of HLA-A+ TLSs and showed that TLS-resident cells increasingly express HLA-A as TLSs mature. Most TLS-resident HLA-A+ cells are tumor-infiltrating T (TIL-T) or tumor-infiltrating B (TIL-B) lymphocytes. Digital spatial profiling of spatially distinct TIL-T lymphocytes and single-cell RNA-seq data from 60 ESCC tumor tissues revealed that CXCL13-expressing exhausted TIL-Ts inside TLSs are reactivated with elevated expression of the APM signature as TLSs mature. Finally, we demonstrated that HLA-A+ TLSs and their major cellular components, TIL-Ts and TIL-Bs, are associated with a clinical benefit from ICB treatment for ESCC. CONCLUSIONS: HLA-A+ TLSs are present in ESCC tumor tissues. TLS-resident TIL-Ts with elevated expression of the APM signature may be reactivated. HLA-A+ TLSs and their major cellular components, TIL-Ts and TIL-Bs, may serve as biomarkers for ICB-treated ESCC patients.

Deep learning on tertiary lymphoid structures in hematoxylin-eosin predicts cancer prognosis and immunotherapy response.

Tertiary lymphoid structures (TLSs) have been associated with favorable immunotherapy responses and prognosis in various cancers. Despite their significance, their quantification using multiplex immunohistochemistry (mIHC) staining of T and B lymphocytes remains labor-intensive, limiting its clinical utility. To address this challenge, we curated a dataset from matched mIHC and H&E whole-slide images (WSIs) and developed a deep learning model for automated segmentation of TLSs. The model achieved Dice coefficients of 0.91 on the internal test set and 0.866 on the external validation set, along with intersection over union (IoU) scores of 0.819 and 0.787, respectively. The TLS ratio, defined as the segmented TLS area over the total tissue area, correlated with B lymphocyte levels and the expression of CXCL13, a chemokine associated with TLS formation, in 6140 patients spanning 16 tumor types from The Cancer Genome Atlas (TCGA). The prognostic models for overall survival indicated that the inclusion of the TLS ratio with TNM staging significantly enhanced the models' discriminative ability, outperforming the traditional models that solely incorporated TNM staging, in 10 out of 15 TCGA tumor types. Furthermore, when applied to biopsied treatment-naïve tumor samples, higher TLS ratios predicted a positive immunotherapy response across multiple cohorts, including specific therapies for esophageal squamous cell carcinoma, non-small cell lung cancer, and stomach adenocarcinoma. In conclusion, our deep learning-based approach offers an automated and reproducible method for TLS segmentation and quantification, highlighting its potential in predicting immunotherapy response and informing cancer prognosis.

Abnormal p16 expression and prognostic significance in esophageal squamous cell carcinoma.

BACKGROUND: The purpose of this study was to analyze p16 expression status and evaluate whether abnormal p16 expression was associated with prognosis in a large-scale esophageal squamous cell carcinoma (ESCC) cohort of patients. METHODS: We retrospectively evaluated p16 expression status of 525 ESCC samples using immunohistochemistry. Associations between abnormal p16 expression and survival were analyzed. RESULTS: P16 negative, focal expression and overexpression were found in 87.6%, 6.9% and 5.5% of ESCC patients. No significant association was observed between abnormal p16 expression and age, sex, tumor site and location, differentiation, vessel and nerve invasion, T stage and lymph node metastasis. In all patients, the survival of p16 focal expression group tended to be better compared with negative group (disease free survival/DFS P=0.040 and overall survival/OS P=0.052) and overexpression group (DFS P=0.201 and OS P=0.258), and there was no survival difference between negative group and overexpression group. The multivariate analysis for OS and DFS found that only clinical stage was a significantly independent prognostic factor (P<0.001). When patients were divided into I-II stage (n=290) and III-IVa stage (n=235), the survival of focal expression group was better compared with negative group (DFS P=0.015 and OS P=0.019), and tended to be better compared with overexpression group (DFS P=0.405 and OS P=0.432) in I-II stage ESCC, which was not found in III-IVa stage ESCC. CONCLUSION: P16 overexpression or negative expression tend to be associated with unfavorable outcomes, especially in I-II stage ESCC. Our study will help to identify a subgroup of ESCC patients with excellent prognosis after surgical therapy.

Identification of Optimal Parameters for Assessing Lymph Node Status of Patients with Esophageal Squamous Cell Carcinoma After Neoadjuvant Chemoradiotherapy.

BACKGROUND: This study aimed to compare the prognostic discrimination power of pretreatment pathologic N stage (prepN), lymph node tumor regression grade (LNTRG), and posttreatment pathologic N (ypN) category for esophageal squamous cell carcinoma (ESCC) patients who received neoadjuvant chemoradiotherapy (nCRT) plus surgery. METHODS: The study reviewed 187 ESCC patients from two medical centers who underwent nCRT plus surgery. Pathologic LNTRG was defined by the proportion of viable tumor area within the tumor bed in lymph nodes (LNs). An average LNTRG then was calculated by averaging the tumor regression grade (TRG) score of all resected LNs. Lymph nodes containing regression changes or vital tumor cells were used for interpretation of the prepN stage, which reflects the estimated number of originally involved LNs. RESULTS: The ypN, prepN, and LNTRG categories had significant prognostic stratification power (p < 0.001, log-rank test). Multivariable cox regression showed that all three categories were independent prognostic factors of disease-free survival (DFS) (p < 0.05). The LNTRG category showed a better prognostic value for DFS prediction than the ypN and prepN categories (Akaike information criterion [AIC]: LNTRG [933.69], ypN [937.56], prepN [937.45]). Additionally, the superior predictive capacity of the LNTRG category was demonstrated by decision curve analysis. Similar results were discovered for patients with remaining diseased LNs. CONCLUSIONS: The three staging categories had prognostic relevance for DFS, with the LNTRG category seeming to have better prognostic indication power. Comprehensive consideration of the ypN status, prepN status, and LN regression may allow for better prognostic stratification of patients.

Proteomic characterization of the colorectal cancer response to chemoradiation and targeted therapies reveals potential therapeutic strategies.

Chemoradiation and targeted therapies are the major treatments for colorectal cancer (CRC); however, molecular properties associated with therapy resistance are incompletely characterized. Here, we profile the proteome of 254 tumor tissues from patients with CRC undergoing chemotherapy, chemoradiation, or chemotherapy combined with targeted therapy. Proteome-based classification reveals four subtypes featured with distinct biological and therapeutic characteristics. The integrative analysis of CRC cell lines and clinical samples indicates that immune regulation is significantly associated with drug sensitivity. HSF1 can increase DNA damage repair and cell cycle, thus inducing resistance to radiation, while high expression of HDAC6 is negatively associated with response of cetuximab. Furthermore, we develop prognostic models with high accuracy to predict the therapeutic response, further validated by parallel reaction monitoring (PRM) assay in an independent validation cohort. This study provides a rich resource for investigating the mechanisms and indicators of chemoradiation and targeted therapy in CRC.

Comparison of two pathological processing methods for large endoscopic submucosal dissection (ESD) specimens.

AIMS: Accurate histopathological evaluation of the endoscopic submucosal dissection (ESD) specimens is essential for clinicians to guide further triage and management. This study aimed to report a novel processing technique for large ESD (≥4 cm) specimens. METHODS: 92 patients with colorectal neoplasms who had undergone ESD were included. 46 ESD specimens were treated with conventional handling process, while the rest 46 cases were given the optimised method. Macrobiocassettes and L-shaped embedding moulds were applied in the optimised method. We evaluated the efficacy of this improved procedure in terms of the number of paraffin blocks, storage space and time consumption of pathological assessment. RESULTS: The average diameter of ESD specimens was 4.5±0.4 cm and 4.7±0.5 cm in the control and test group (p=0.023), respectively. In control group, 398 paraffin blocks of 46 cases were obtained. With the same cases number and larger lesion size, only 276 blocks were achieved in test group (p<0.001). As for the storage space, the total volume of paraffin blocks and slides (4554.0 cm3 and 1207.5 cm3) of optimised method was significantly reduced compared with the control group (6208.8 cm3 and 1741.3 cm3) (p=0.001, p<0.001). In addition, the optimised method was superior to the conventional one in shortening time consumption of pathological assessment (164.5 min and 269.0 min, p<0.001). CONCLUSIONS: The optimised technique not only reduced the workload and storage space, but also facilitated accurate pathological assessment.

Prognostic significance of CCND1 amplification/overexpression in smoking patients with esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal cancer, with 5-year survival rate less than 30%. In order to offer an individual therapeutic approach, it is necessary to identify novel prognostic factors to recognize high-risk patients. Given the high frequency of CCND1 abnormalities and the important biological effects of smoking in ESCC, we explored the potential relationship between CCND1 abnormalities and smoking in ESCC patients. CCND1 status was examined by fluorescence in situ hybridization and immunohistochemical staining in ESCC tissue microarrays (n = 519). CCND1 amplification and cyclinD1 overexpression were found in 53.2 and 34.1% ESCC, respectively. CCND1 amplification (P = 0.142 for DFS and P = 0.191 for OS) and cyclinD1 overexpression (P = 0.035 for DFS and P = 0.092 for OS) tended to be poorer prognostic factors in all patients. Among smoking patients, those with CCND1 amplification had significantly poorer prognosis, with a median DFS and OS of 25.0 and 30.0 months compared to not reached and 52.0 months for those without CCND1 amplification (P = 0.020 and 0.018). A similar trend was found in the 68 patients with cyclinD1 overexpression (P = 0.043 and 0.048). Further univariate and multivariate analysis revealed CCND1 amplification was independently poorer prognostic factor in smoking patients, which was not found in non-smoking patients. Smokers with CCND1 amplification or cyclinD1 overexpression have poorer survival, which help us to identify distinct groups of patients with apparently poorer outcome and would enable appropriate follow-up and treatment strategies.

Development and Validation of PET/CT-Based Nomogram for Preoperative Prediction of Lymph Node Status in Esophageal Squamous Cell Carcinoma.

PURPOSE: This study was conducted to predict the lymph node status and survival of esophageal squamous cell carcinoma before treatment by PET-CT-related parameters. METHODS: From January 2013 to July 2018, patients with pathologically diagnosed ESCC at our hospital were retrospectively enrolled. Completed esophagectomy and two- or three-field lymph node dissections were conducted. Those with neoadjuvant therapy were excluded. The first 65% of patients in each year were regarded as the training set and the last 35% as the test set. Nomogram was constructed by the "rms" package. Five-year, overall survival was analyzed based on the best cutoff value of risk score determined by the "survivalROC" package. RESULTS: Ultimately, 311 patients were included with 209 in the training set and 102 in the test set. The positive rate of the lymph node in the training set was 36.8% and that in the test set was 32.4%. The C-index of the training set was 0.763 and the test set was 0.766. The decision curve analysis showed that it was superior to the previous methods based on lymph node uptake or long/short axis diameter or axial ratio. Risk score > 0.20 was significantly associated with 5-year, overall survival (p = 0.0015) in all patients. CONCLUSIONS: The nomogram constructed from PET-CT parameters including primary tumor metabolic length and thickness can accurately predict the risk of lymph node metastasis in ESCC. The risk score calculated by our model accurately predicts the patient's 5-year overall survival.

Prognostic significance of CDK6 amplification in esophageal squamous cell carcinoma.

Dysregulation of CDK6 plays crucial roles in the carcinogenesis of many kinds of human malignancies. However, the role of CDK6 in esophageal squamous cell carcinoma (ESCC) is not well known. We investigated the frequency and prognostic value of CDK6 amplification to improve the risk stratification in patients with ESCC. Pan-cancer analysis of CDK6 was conducted on The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx) and Gene Expression Omnibus (GEO) databases. CDK6 amplification was detected in 502 ESCC samples by Fluorescence in situ hybridization (FISH) through tissue microarrays (TMA). Pan-cancer analysis revealed that CDK6 mRNA level was much higher in multiple kinds of cancers and higher CDK6 mRNA level indicated a better prognosis in ESCC. In this study, CDK6 amplification was detected in 27.5% (138/502) of patients with ESCC. CDK6 amplification was significantly correlated with tumor size (p = 0.044). Patients with CDK6 amplification tended to have a longer disease-free survival (DFS) (p = 0.228) and overall survival (OS) (p = 0.200) compared with patients without CDK6 amplification but of no significance. When further divided into I-II and III-IV stage, CDK6 amplification was significantly associated with longer DFS and OS in III-IV stage group (DFS, p = 0.036; OS, p = 0.022) rather than in I-II stage group (DFS, p = 0.776; OS, p = 0.611). On univariate and multivariate analysis of Cox hazard model, differentiation, vessel invasion, nerve invasion, invasive depth, lymph node metastasis and clinical stage were significantly associated with DFS and OS. Moreover, invasion depth was an independent factor for ESCC prognosis. Taken together, for ESCC patients in III-IV stage, CDK6 amplification indicated a better prognosis.

Comprehensive proteogenomic characterization of early duodenal cancer reveals the carcinogenesis tracks of different subtypes.

The subtypes of duodenal cancer (DC) are complicated and the carcinogenesis process is not well characterized. We present comprehensive characterization of 438 samples from 156 DC patients, covering 2 major and 5 rare subtypes. Proteogenomics reveals LYN amplification at the chromosome 8q gain functioned in the transmit from intraepithelial neoplasia phase to infiltration tumor phase via MAPK signaling, and illustrates the DST mutation improves mTOR signaling in the duodenal adenocarcinoma stage. Proteome-based analysis elucidates stage-specific molecular characterizations and carcinogenesis tracks, and defines the cancer-driving waves of the adenocarcinoma and Brunner's gland subtypes. The drug-targetable alanyl-tRNA synthetase (AARS1) in the high tumor mutation burden/immune infiltration is significantly enhanced in DC progression, and catalyzes the lysine-alanylation of poly-ADP-ribose polymerases (PARP1), which decreases the apoptosis of cancer cells, eventually promoting cell proliferation and tumorigenesis. We assess the proteogenomic landscape of early DC, and provide insights into the molecular features corresponding therapeutic targets.

Integrative proteogenomic characterization of early esophageal cancer.

Esophageal squamous cell carcinoma (ESCC) is malignant while the carcinogenesis is still unclear. Here, we perform a comprehensive multi-omics analysis of 786 trace-tumor-samples from 154 ESCC patients, covering 9 histopathological stages and 3 phases. Proteogenomics elucidates cancer-driving waves in ESCC progression, and reveals the molecular characterization of alcohol drinking habit associated signatures. We discover chromosome 3q gain functions in the transmit from nontumor to intraepithelial neoplasia phases, and find TP53 mutation enhances DNA replication in intraepithelial neoplasia phase. The mutations of AKAP9 and MCAF1 upregulate glycolysis and Wnt signaling, respectively, in advanced-stage ESCC phase. Six major tracks related to different clinical features during ESCC progression are identified, which is validated by an independent cohort with another 256 samples. Hyperphosphorylated phosphoglycerate kinase 1 (PGK1, S203) is considered as a drug target in ESCC progression. This study provides insight into the understanding of ESCC molecular mechanism and the development of therapeutic targets.

Distribution of residual tumors in esophageal squamous cell carcinoma after neoadjuvant PD-1 blockade combined with chemotherapy.

Aims: The distribution of residual esophageal squamous cell carcinoma (ESCC) in the esophageal wall and resected lymph nodes was evaluated after neoadjuvant chemoimmunotherapy (nICT). Methods and results: Clinical data were collected from 137 ESCC patients who underwent anti-programmed death 1 therapy and esophagectomy. Ninety (65.7%) achieved an major pathological response (MPR) in the esophageal wall, and 27 (19.7%) achieved an MPR in the lymph nodes. Pathologically complete response (pCR, ypT0N0) was observed in 26 patients (19%). Residual tumors located in the mucosa and/or submucosa were found in 94.6% of nonpCR patients. In the minor responders, 97.8% had residual tumor >10% in the mucosa or submucosa. A preferential regression direction toward the lumen was found in 76.4% of prepT2 nonpCR patients, or 60.7% of prepT3-4a nonpCR patients. The correlation between pCR in the esophageal wall and in lymph nodes was not significant (P=0.143). Among 19 patients with pCR in resected recurrent laryngeal nerve (RLN) lymph nodes, 31.6% had residual tumor cells in other resected lymph nodes. A significant correlation was found between ypT/ypN downstaging and tumor regression grade (P<0.05). Conclusions: After nICT for ESCC, residual tumors were frequently found in the mucosa or submucosa, with relatively high responsiveness of the invasive front and a significant correlation with downstaging, which may help clinicians make appropriate decisions about postoperative treatment and surveillance. The differences in pCR status in primary tumors, resected lymph nodes, and RLN lymph nodes indicated the importance of assessing regression changes in all resected lymph nodes during clinical practice.

A comparative analysis of clinicopathological factors and survival between esophageal basaloid squamous cell carcinoma and conventional esophageal squamous cell carcinoma.

INTRODUCTION: Recently, the number of diagnosed esophageal basaloid squamous cell carcinoma (EBSCC) has gradually increased. However, available data on EBSCC are limited to date. METHODS: A total of 165 EBSCC (Cohort 1) and 515 conventional esophageal squamous cell carcinoma (ESCC) (Cohort 2) were retrospectively analyzed. RESULTS: In Cohort 1, 70 cases only had invasive EBSCC component (42.4%, defined as Group 1), 73 cases had concomitant invasive ESCC component (44.2%, Group 2), and 22 had concomitant invasive poor-differentiated component (13.3%, Group 3). Lymph node metastasis rates of Group 3, Group 2 and Group 1 were ranked from high to low (P = 0.044). There were higher patient age (P = 0.047), smaller tumor size (P = 0.009), more nerve invasion (P < 0.001), and lower pTNM stage (P < 0.001) in EBSCC (Cohort 1), compared with ESCC (Cohort 2). In Cohort 1 and Cohort 2, pTNM stage was an independent prognostic factor for both DFS and OS. No significant survival difference was found between EBSCC (Cohort 1) and ESCC (Cohort 2) in pIA-B stage, pIIA-B stage, pIIIA-B stage and pIVA-B stage (P > 0.05). CONCLUSION: Our analysis of the largest EBSCC series from a single institution to date with conventional ESCC demonstrated that EBSCC carried a similar prognosis with ESCC in pIA-B stage, pIIA-B stage, pIIIA-B stage and pIVA-B stage. And pure EBSCC, didn't have poorer survival than mixed EBSCC with concomitant ESCC or other components. Our findings may be valuable in the better understanding of EBSCC's biological behaviors, and the related molecular mechanism is needed to be explored in the future.

Proteogenomics of diffuse gliomas reveal molecular subtypes associated with specific therapeutic targets and immune-evasion mechanisms.

Diffuse gliomas are devastating brain tumors. Here, we perform a proteogenomic profiling of 213 retrospectively collected glioma tumors. Proteogenomic analysis reveals the downstream biological events leading by EGFR-, IDH1-, TP53-mutations. The comparative analysis illustrates the distinctive features of GBMs and LGGs, indicating CDK2 inhibitor might serve as a promising drug target for GBMs. Further proteogenomic integrative analysis combined with functional experiments highlight the cis-effect of EGFR alterations might lead to glioma tumor cell proliferation through ERK5 medicates nucleotide synthesis process. Proteome-based stratification of gliomas defines 3 proteomic subgroups (S-Ne, S-Pf, S-Im), which could serve as a complement to WHO subtypes, and would provide the essential framework for the utilization of specific targeted therapies for particular glioma subtypes. Immune clustering identifies three immune subtypes with distinctive immune cell types. Further analysis reveals higher EGFR alteration frequencies accounts for elevation of immune check point protein: PD-L1 and CD70 in T-cell infiltrated tumors.

The efficacy of additional surgical resection after endoscopic resection in pT1b esophageal squamous cell carcinoma: A multi-institutional retrospective study in China.

BACKGROUND: pT1b esophageal squamous cell carcinoma (ESCC) patients treated by endoscopic resection (ER) required additional treatment with surgical resection (SR) or chemoradiotherapy (CRT) according to 2020 Japan Gastroenterological Endoscopy Society (JGES) guideline. Given the evidences for this recommendation were largely based on small-size studies, our study collected 166 cases of ER-treated pT1b patients in order to investigate the efficacy of additional SR as compared to ER-alone treatment. METHODS: A multi-institutional retrospective study in China was conducted. The pT1b ESCC treated by ER + SR (n = 42) and ER-alone (n = 124) from 2007 to 2018 were recruited. Meanwhile, patients with positive lymphovascular invasion (LVI(+)) and/or with positive vertical margin (VM(+)) were put into high-risk group, and those with both VM(-) and LVI(-) were selected into low-risk group. The clinicopathological parameters, lymph node metastasis (LNM), and survival between ER + SR and ER-alone groups were analyzed. RESULTS: In high-risk group, concurrent LNM revealed in surgically resected specimens accounted for 52.6% cases in ER + SR group. After surgical removal, the incidence of post-resection LNM dropped down to 5.6%. However, in low-risk group, patients with ER + SR treatment did not exhibit any concurrent LNM in surgically resected specimens, and the incidence of their overall LNM was similar to that in ER-alone group (0% vs. 2.8%, p = 1.000). More importantly, these cases demonstrated significantly shorter overall survival (OS) than that in ER-alone group (81.8% and 100.0%, respectively, at 3 years; log-Rank: P = 0.010). CONCLUSIONS: For ER-treated pT1b patients in high-risk group, additional SR is strongly recommended. However, for those in low-risk group, additional SR does not generate much benefit for clearance of LNM, but brings harm to shorten their OS. Therefore, additional SR is not recommended for ER-treated pT1b patient in low-risk group.

Identification of clinical prognostic features of esophageal cancer based on m6A regulators.

Background: Esophageal cancer (ESCA) is a common malignancy with high morbidity and mortality. n6-methyladenosine (m6A) regulators have been widely recognized as one of the major causes of cancer development and progression. However, for ESCA, the role of regulators is unclear. The aim of this study was to investigate the role of m6A RNA methylation regulators in the immune regulation and prognosis of ESCA. Methods: RNA-seq data were downloaded using the Cancer Genome Atlas (TCGA) database, and the expression differences of m6A RNA methylation regulators in ESCA were analyzed. Further m6A methylation regulator markers were constructed, and prognostic and predictive values were assessed using survival analysis and nomograms. Patients were divided into low-risk and high-risk groups. The signature was evaluated in terms of survival, single nucleotide polymorphism (SNP), copy number variation (CNV), tumor mutation burden (TMB), and functional enrichment analysis (TMB). The m6A expression of key genes in clinical specimens was validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results: In ESCA tissues, most of the 23 regulators were significantly differentially expressed. LASSO regression analysis included 7 m6A-related factors (FMR1, RBMX, IGFBP1, IGFBP2, ALKBH5, RBM15B, METTL14). In addition, this study also identified that the risk model is associated with biological functions, including base metabolism, DNA repair, and mismatch repair. In this study, a nomogram was created to predict the prognosis of ESCA patients. Bioinformatics analysis of human ESCA and normal tissues was performed using qRT-PCR. Finally. Seven genetic features were found to be associated with m6A in ESCA patients. The results of this study suggest that three different clusters of m6A modifications are involved in the immune microenvironment of ESCA, providing important clues for clinical diagnosis and treatment.

Proteomic characterization of gastric cancer response to chemotherapy and targeted therapy reveals new therapeutic strategies.

Chemotherapy and targeted therapy are the major treatments for gastric cancer (GC), but drug resistance limits its effectiveness. Here, we profile the proteome of 206 tumor tissues from patients with GC undergoing either chemotherapy or anti-HER2-based therapy. Proteome-based classification reveals four subtypes (G-I-G-IV) related to different clinical and molecular features. MSI-sig high GC patients benefit from docetaxel combination treatment, accompanied by anticancer immune response. Further study reveals patients with high T cell receptor signaling respond to anti-HER2-based therapy; while activation of extracellular matrix/PI3K-AKT pathway impair anti-tumor effect of trastuzumab. We observe CTSE functions as a cell intrinsic enhancer of chemosensitivity of docetaxel, whereas TKTL1 functions as an attenuator. Finally, we develop prognostic models with high accuracy to predict therapeutic response, further validated in an independent validation cohort. This study provides a rich resource for investigating the mechanisms and indicators of chemotherapy and targeted therapy in GC.