PURPOSE: Claudin 18 isoform 2 (CLDN18.2) is an emerging biomarker and therapeutic target in gastric and gastroesophageal junction (G/GEJ) adenocarcinoma. This study aimed to obtain deeper understanding of CLDN18.2 positivity patterns, prognostic implications, and associations with various demographic, clinical, and molecular characteristics in G/GEJ adenocarcinoma. METHODS: Archived tumor tissue samples from 304 patients with G/GEJ adenocarcinoma in the United States were assessed for CLDN18.2 positivity by immunohistochemistry. CLDN18.2 positivity was defined as ≥50% or ≥75% of tumor cells with CLDN18 staining intensity ≥2+. CLDN18.2 positivity patterns were analyzed for association with prognosis and clinicopathologic/demographic characteristics. Where possible, CLDN18.2 positivity was analyzed for matched tissue samples to assess concordance between primary and metastatic tumors and concordance before and after chemotherapy. RESULTS: The overall prevalence of CLDN18.2-positive tumors (with ≥75% cutoff) was 44.4% (n = 135 of 304). CLDN18.2-positive tumors had a prevalence of 51.4% (n = 91 of 177) in gastric and 34.6% (n = 44 of 127) in GEJ adenocarcinoma. With a ≥50% cutoff, the prevalence of CLDN18.2-positive tumors was 64.4% (n = 114 of 177) in gastric adenocarcinoma and 44.9% (n = 57 of 127) in GEJ adenocarcinoma. There was no association between overall survival and CLDN18.2 positivity using either threshold. Statistically significant associations were noted between CLDN18.2 positivity and sex, histologic type of G/GEJ adenocarcinoma, and adenocarcinoma subtype (≥75% cutoff), and metastasis site and tumor grade (≥50% cutoff). The overall concordance of CLDN18.2 positivity (≥75% cutoff) was 73% (27 of 37) for matched primary versus metastatic tumor samples and 74% (29 of 39) for matched samples before and after chemotherapy. CONCLUSION: This study demonstrated that CLDN18.2 positivity did not correlate with survival in G/GEJ adenocarcinoma, consistent with published data. On the basis of matched sample analysis, CLDN18.2 appears to demonstrate >70% concordance as a biomarker. Observed correlations with certain patient/tumor characteristics warrant further study.

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy with limited therapeutic options and poor overall survival. In recent years, advances in genomic profiling have revealed the complex molecular and cellular heterogeneity of PDAC, offering new avenues for therapeutic intervention. This review explores emerging therapeutic strategies targeting dysregulated molecular pathways, along with the tumor microenvironment that shown promise in overcoming drug resistance. Novel immunotherapy strategies, such as immune checkpoint inhibitors and CAR T-cell therapies, are currently being explored in an attempt to modulate PDAC immunosuppressive microenvironment. Additionally, we highlight recent clinical trials over the last 5 years and innovative therapeutic strategies aiming to improve outcomes in PDAC. Significant progress in genomic profiling, targeted therapies and immunotherapy is a shaping the treatment of PDAC. Despite challenges posed by its dense stroma and immune suppressive microenvironment, novel strategies such as IL 6 and CD137 inhibitors, CAR-T and therapeutic cancer vaccines are promising. KRAS targeted therapies are expanding beyond G12C inhibitors, with novel drugs in development that will further improve treatment options. Additionally, tumor treating fields (TTF) are being investigated in locally advanced PDAC, with the PANOVA-3 trial potentially integrating this modality into future treatment strategies. Continued advancements in these areas will significantly enhance PDAC outcomes.

Objective: Prognosis of patients with advanced oesophagogastric adenocarcinoma (mEGAC) is poor and molecular determinants of shorter or longer overall survivors are lacking. Our objective was to identify molecular features and develop a prognostic model by profiling the genomic features of patients with mEGAC with widely varying outcomes. Design: We profiled 40 untreated mEGACs (20 shorter survivors 36 months) with whole-exome sequencing (WES) and RNA sequencing and performed an integrated analysis of exome, transcriptome, immune profile and pathological phenotypes to identify the molecular determinants, developing an integrated model for prognosis and comparison with The Cancer Genome Atlas (TCGA) cohorts. Results: KMT2C alterations were exclusively observed in shorter survivors together with high level of intratumour heterogeneity and complex clonal architectures, whereas the APOBEC mutational signatures were significantly enriched in longer survivors. Notably, the loss of heterozygosity in chromosome 4 (Chr4) was associated with shorter survival and ‘cold’ immune phenotype characterised by decreased B, CD8, natural killer cells and interferon-gamma responses. Unsupervised transcriptomic clustering revealed a shorter survivor subtype with distinct expression features (eg, upregulated druggable targets JAK2, MAP3K13 and MECOM ). An integrated model was then built based on clinical variables and the identified molecular determinants, which significantly segregated shorter and longer survivors. All the above features and the integrated model have been validated independently in multiple TCGA cohorts. Conclusion: This study discovered novel molecular features prognosticating overall survival in patients with mEGAC and identified potential novel targets in shorter survivors.

Objective: We aimed to evaluate the frequency of paratracheal lymph nodes (LN) metastases and their prognostic influence. Summary Background Data: Paratracheal LNs are considered regional nodes in the esophageal cancer classification, but their metastatic rate and influence on survival remain unclear. Methods: One thousand one hundred ninety-nine patients with resectable esophageal or gastroesophageal junction adenocarcinoma (EAC) (January 2002 and December 2016) in our Gastrointestinal Medical Oncology Database were analyzed. Paratracheal LNs were defined as1R, 1L, 2R, 2L, 4R, and 4L, according to the 8th American Joint Committee on Cancer classification. Results: Of 1199 patients, 73 (6.1%) had positive paratracheal LNs at diagnosis. The median overall survival (OS) of 73 patients with initial paratracheal LN involvement was 2.10 years (range 0.01–10.1, 5-yrs OS 24.2%). Of 1071 patients who were eligible for recurrence evaluation, 70 patients (6.5%) developed paratracheal LN metastases as the first recurrence. The median time to recurrence was 1.28 years (range 0.28–5.96 yrs) and the median OS following recurrence was only 0.95 year (range 0.03–7.88). OS in 35 patients who had only paratracheal LN recurrence was significantly longer than in patients who had other recurrences (median OS 2.26 vs 0.51 yrs, 5-yrs OS; 26.8% vs 0%, P < 0.0001). Higher T stage (T3/T4) was an independently risk factor for paratracheal LN recurrence (odds ratio 5.10, 95% confidence interval 1.46–17.89). We segregated patients in 3 groups based on the distance of tumor's proximal edge to esophagogastric junction (low; ≤2 cm, medium; 2.0–7.0 cm, and high; >7.0 cm). Paratracheal LN metastases were more frequent with the proximal tumors (low, 4.2%; medium, 12.0%; high, 30.3%; Cochran–Armitage Trend test, P < 0.001). Conclusion: Paratracheal LN metastases were associated with a shorter survival in resectable EAC patients. Alternate approaches to prolong survival of this group of patients are warranted.