Calcium Electroporation for Management of Cutaneous Metastases in HER2-Positive Breast Cancer: A Case Report

Immune cell populations in the tumour environment following calcium electropora-tion for cutaneous metastasis: a histopathological study

BACKGROUND AND PURPOSE

Calcium electroporation (CaEP) involves injecting calcium into tumour tissues and using electrical pulses to create membrane pores that induce cell death. This study assesses resultant immune responses and histopathological changes in patients with cutaneous metastases.

PATIENTS/MATERIALS AND METHODS

The aimed cohort comprised 24 patients with metastases exceeding 5 mm. Tumours were treated once with CaEP (day 0) or twice (day 28). Biopsies were performed on days 0 and 2, with additional samples on days 7, 28, 30, 35, 60, and 90 if multiple tumours were treated. The primary endpoint was the change in tumour-infiltrating lymphocytes (TILs) two days post-treatment, with secondary endpoints evaluating local and systemic immune responses via histopathological analysis of immune markers, necrosis, and inflammation.

RESULTS

Seventeen patients, with metastases primarily from breast cancer (14 patients), but also lung cancer (1), melanoma (1), and urothelial cancer (1), completed the study. Of the 49 lesions treated, no significant changes in TIL count or PD-L1 expression were observed. However, there was substantial necrosis and a decrease in FOXP3-expression (p = 0.0025) noted, with a slight increase in CD4+ cells but no changes in CD3, CD8, or CD20 expressions. Notably, four patients showed reduced tumour invasiveness, including one case of an abscopal response.

INTERPRETATION

This exploratory study indicates that CaEP can be an effective anti-tumour therapy potentially enhancing immunity. Significant necrosis and decreased regulatory lymphocytes were observed, although TIL count remained unchanged. Several patients exhibited clinical signs of immune response following treatment.

Calcium electroporation of esophageal cancer induces gene expression changes: a sub-study of a phase I clinical trial

PURPOSE

In this study, we aim to investigate gene expression changes in tumor samples obtained from patients with esophageal cancer treated with calcium electroporation. Previously, local treatment with calcium electroporation has been shown to induce gene expression alterations, potentially contributing to a more tumor-hostile microenvironment.

METHODS

In this sub-study of a phase I clinical trial, we included five patients with esophageal cancer treated with calcium electroporation. We compared cancer-associated gene expression patterns in tumor samples before and after treatment. Furthermore, we used linear support vector regression to predict the cellular composition of tumor samples.

RESULTS

Using differential expression analysis, we identified the downregulation of CXCL14 and upregulation of CCL21, ANGPTL4, and CRABP2 genes. We also found a decreased predicted proportion of dendritic cells while the proportion of neutrophils was increased.

CONCLUSION

This study provides evidence that calcium electroporation for esophageal cancer induces local transcriptional changes and possibly alters the cellular composition of the tumor microenvironment. The results are explorative, larger studies are needed to confirm and further correlate our findings with clinical outcomes.

Calcium electroporation in cutaneous metastases - A non-randomised phase II multicentre clinical trial

BACKGROUND

Cutaneous metastases can cause distressing symptoms and be challenging to treat. Local therapies are essential in management. Calcium electroporation uses calcium and electrical pulses to selectively kill cancer cells. This multicentre study aimed to define response in cutaneous metastases across different cancer types.

METHODS

Patients with tumours ≤3 cm of any histology were included (stable or progressing on current therapy ≥2 months), at three centres. Tumours were treated with 220 mM calcium chloride injection and manual application of eight 0.1 ms pulses with 1 kV/cm and 1Hz with a handheld electrode, in local or general anaesthesia. Clinical response was evaluated after 1, 2, 3, 4, 5, 6, and 12 months. Primary endpoint was response at two months. The overall response rate (ORR) was partial- and complete responses of treated tumours. MR-imaging and qualitative interviews were performed in respective subsets.

RESULTS

Nineteen patients with disseminated cancer (breast n = 4, lung n = 5, pancreatic n = 1, colorectal n = 2, gastric n = 1, and endometrial cancer n = 1) were enrolled, and 58 metastases were treated (50 once, 8 retreated). The ORR was 36% (95% CI 22-53) after two months. Best ORR was 51% (CR 42%; PR 9%). Previous irradiation improved outcomes (p = 0.0004). Adverse events were minimal. Median pain score was reduced after two months (p = 0.017). Treatment may relieve symptoms according to qualitative interviews. MRI showed restriction in treated tissue.

CONCLUSION

The majority of tumours were treated only once with calcium electroporation, achieving an ORR of 36% after two months and best ORR of 51%. Efficacy, symptom-relief and safety support calcium electroporation as a palliative treatment option for cutaneous metastases.

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

Calcium Homeostasis in the Development of Resistant Breast Tumors

Cancer is one of the main health problems worldwide. Only in 2020, this disease caused more than 19 million new cases and almost 10 million deaths, with breast cancer being the most diagnosed worldwide. Today, despite recent advances in breast cancer treatment, a significant percentage of patients will either not respond to therapy or will eventually experience lethal progressive disease. Recent studies highlighted the involvement of calcium in the proliferation or evasion of apoptosis in breast carcinoma cells. In this review, we provide an overview of intracellular calcium signaling and breast cancer biology. We also discuss the existing knowledge on how altered calcium homeostasis is implicated in breast cancer development, highlighting the potential utility of Ca2+ as a predictive and prognostic biomarker, as well as its potential for the development of new pharmacological treatments to treat the disease.