Claudin-18 expression in small bowel adenocarcinoma: a clinico-pathologic study

Synthesis, preclinical evaluation and pilot clinical translation of [68Ga]Ga-PMD22, a novel nanobody PET probe targeting CLDN18.2 of gastrointestinal cancer

PURPOSE

Claudin18.2 (CLDN18.2) is a novel target for diagnosis and therapy of gastrointestinal cancer. This study aimed to evaluate the safety and feasibility of a novel CLDN18.2-targeted nanobody, PMD22, labeled with gallium-68 ([68Ga]Ga), for detecting CLDN18.2 expression in patients with gastrointestinal cancer using PET/CT imaging.

METHODS

[68Ga]Ga-PMD22 was synthesized based on the nanobody, and its cell binding properties were assayed. Preclinical pharmacokinetics were determined in CLDN18.2-positive xenografts using microPET/CT. Effective dosimetry of [68Ga]Ga-PMD22 was evaluated in 5 gastrointestinal cancer patients, and PET/CT imaging of [68Ga]Ga-PMD22 and [18F]FDG were performed head-to-head in 16 gastrointestinal cancer patients. Pathological tissues were obtained for CLDN18.2 immunohistochemical (IHC) staining and comparative analysis with PET/CT findings.

RESULTS

Cell binding assay showed that [68Ga]Ga-PMD22 had a higher binding ability to AGSCLDN18.2 and BGC823CLDN18.2 cells than to AGS and BGC823 cells (p < 0.001). MicroPET/CT images showed that [68Ga]Ga-PMD22 rapidly accumulated in AGSCLDN18.2 and BGC823CLDN18.2 tumors, and high contrast tumor to background imaging was clearly observed. In the pilot study, the effective dose of [68Ga]Ga-PMD22 was 1.68E-02 ± 1.45E-02 mSv/MBq, and the CLDN18.2 IHC staining result was highly correlated with the SUVmax/BKGstomach of [68Ga]Ga-PMD22 (rs = 0.848, p < 0.01).

CONCLUSION

A novel [68Ga]Ga-labeled nanobody probe targeting CLDN18.2, [68Ga]Ga-PMD22, was established and preliminarily proved to be safe and effective in revealing CLDN18.2-positive gastrointestinal cancer, providing a basis for the clinical translation of the agent.

CLINICAL TRIAL REGISTRATION

This study was registered on the ClinicalTrials.gov (NCT05937919).

Claudin 18.2 as a novel therapeutic target

Claudin 18.2, a tight-junction molecule predominantly found in the nonmalignant gastric epithelium, becomes accessible on the tumour cell surface during malignant transformation, thereby providing an appealing target for cancer therapy. Data from two phase III trials testing the anti-claudin 18.2 antibody zolbetuximab have established claudin 18.2-positive advanced-stage gastric cancers as an independent therapeutic subset that derives benefit from the addition of this agent to chemotherapy. This development has substantially increased the percentage of patients eligible for targeted therapy. Furthermore, newer treatments, such as high-affinity monoclonal antibodies, bispecific antibodies, chimeric antigen receptor T cells and antibody-drug conjugates capable of bystander killing effects, have shown considerable promise in patients with claudin 18.2-expressing gastric cancers. This new development has resulted from drug developers moving beyond traditional targets, such as driver gene alterations or growth factors. In this Review, we highlight the biological rationale and explore the clinical activity of therapies that target claudin 18.2 in patients with advanced-stage gastric cancer and explore the potential for expansion of claudin 18.2-targeted therapies to patients with other claudin 18.2-positive solid tumours.

Claudin 18.2 expression in digestive neuroendocrine neoplasms: a clinicopathological study

BACKGROUND

Claudin 18.2-targeted therapy has shown significant efficacy in treating claudin 18.2-positive cancers. However, limited systematic studies have investigated characteristics of claudin 18.2 expression in neuroendocrine neoplasms (NENs).

METHODS

Data and specimens from 403 cases of digestive NENs were retrospectively collected, and claudin 18.2 expression was detected using immunochemical staining.

RESULTS

Claudin 18.2 was positive in 19.6% (79/403) of the digestive NENs. The highest positive rate of claudin 18.2 was observed in gastric NENs (72/259, 27.8%), accounting for 91.1% (72/79) of all positive cases. The positivity rate was significantly higher in gastric NENs compared to pancreatic (2/78, 2.6%) or colorectal NENs (2/38, 5.3%; p < 0.05). For digestive NENs, claudin 18.2 positivity was significantly higher in neuroendocrine carcinomas (NECs) (37/144, 25.7%) than in neuroendocrine tumours (NETs; 14/160, 8.8%; p < 0.001), but no significant difference was found between gastric NECs (59/213, 27.7%) and gastric NETs (13/46, 28.3%; p > 0.05). The positivity was significantly higher in large-cell NECs (LCNECs; 28/79, 35.4%) and MiNEN (mixed neuroendocrine-non- neuroendocrine neoplasms)-LCNECs (23/66, 34.8%) compared to small-cell NECs (SCNECs; 9/65, 13.8%) and MiNEN-SCNECs (5/33, 15.2%; p < 0.05). Claudin 18.2 expression was more prevalent in gastric NENs than in pancreatic (12.5 ×; p = 0.001) and colorectal NENs (5.9 ×; p = 0.021). Claudin 18.2 staining was a useful method for identify the gastric origins of NETs, with a sensitivity of 28.3% and a specificity of 99.1%.

CONCLUSION

The expression characteristics of claudin 18.2 in NENs were characterized, which may provide a clinicopathological reference for targeted therapies in patients with NENs.

Claudin18.2 expression in pulmonary mucinous adenocarcinoma

BACKGROUND

Pulmonary invasive mucinous adenocarcinoma (IMA) is a unique type of lung adenocarcinoma with a high recurrence rate and limited treatment strategies. The tight-junction-associated protein claudin18.2 is a new therapeutic target for several solid tumors. This study aimed to detect the expression of claudin18.2 in IMA and its clinicopathological association with the disease.

METHODS

 The expression of claudin18.2 was immunohistochemically evaluated in an IMA cohort of 84 patients, who underwent partial pneumonectomy between January 2017 and December 2021. Positive staining for claudin18.2 was defined as ≥ 10% of tumor cells showing ≥ 1 + membrane staining or any ≥ 2 + membrane staining.

RESULTS

Claudin18.2 was detected in 76.2% (64/84) of IMA patients, significantly higher than that in non-mucinous adenocarcinoma (NMA). 46.4% (39/84) of the IMA patients met the enrollment criteria of the clinical trials of monoclonal antibodies (≥ 75% of tumor cells demonstrating ≥ 2 + staining intensity). Positive staining for claudin18.2 was significantly associated with smaller tumor size (p = 0.010), less pleural invasion (p = 0.019), and earlier pN stage (p < 0.001). Expression of claudin18.2 was not related to prognosis in multivariate analysis.

CONCLUSIONS

To summarize, in this study we found that claudin18.2 was remarkably highly expressed in IMA and the overexpression was associated with low invasive capacity. Thus, this protein appears to be a promising therapeutic target and deserves further investigation in IMA patients.

Mismatch repair deficiency as prognostic factor for stage III small bowel adenocarcinoma: A multicentric international study

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare cancer with an aggressive behavior. No study has specifically addressed the putative prognostic role of mismatch repair status in stage III SBAs.

AIMS

We aimed to investigate whether mismatch repair deficiency is associated with cancer-specific survival in a Western cohort of patients with stage III SBAs.

METHODS

In this retrospective multicentric international cohort study, we enrolled 70 patients who underwent surgically resection for stage III SBAs and we analyzed the frequency of mismatch repair deficiency, tested by immunohistochemistry for mismatch repair proteins and by polymerase chain reaction for microsatellite instability, and its association with cancer-specific survival and other clinic-pathologic factors.

RESULTS

We found sixteen (23%) patients with mismatch repair deficient adenocarcinoma, without discordance between immunohistochemical and polymerase chain reaction for microsatellite instability analyses. Mismatch repair deficiency proved to be associated with a better outcome both at univariable analysis (hazard ratio: 0.28, 95% confidence interval: 0.08-0.91, p: 0.035) and in bivariable models adjusted for patient age or gender, tumor site, pT4 stage, tumor budding, and perineural invasion.

CONCLUSION

This study highlights the importance of testing mismatch repair status to improve prognostic stratification in stage III SBAs.

Malignancies in Patients with Celiac Disease: Diagnostic Challenges and Molecular Advances

Celiac disease (CD) is a multiorgan autoimmune disorder of the chronic intestinal disease group characterized by duodenal inflammation in genetically predisposed individuals, precipitated by gluten ingestion. The pathogenesis of celiac disease is now widely studied, overcoming the limits of the purely autoimmune concept and explaining its hereditability. The genomic profiling of this condition has led to the discovery of numerous genes involved in interleukin signaling and immune-related pathways. The spectrum of disease manifestations is not limited to the gastrointestinal tract, and a significant number of studies have considered the possible association between CD and neoplasms. Patients with CD are found to be at increased risk of developing malignancies, with a particular predisposition of certain types of intestinal cancer, lymphomas, and oropharyngeal cancers. This can be partially explained by common cancer hallmarks present in these patients. The study of gut microbiota, microRNAs, and DNA methylation is evolving to find the any possible missing links between CD and cancer incidence in these patients. However, the literature is extremely mixed and, therefore, our understanding of the biological interplay between CD and cancer remains limited, with significant implications in terms of clinical management and screening protocols. In this review article, we seek to provide a comprehensive overview of the genomics, epigenomics, and transcriptomics data on CD and its relation to the most frequent types of neoplasms that may occur in these patients.