Effects of Multifrequency Electromagnetic Pulses on tumor growth in immunocompetent mice.

We previously established that a Multifrequency Electromagnetic Pulse (MEMP) treatment selectively eradicates tumorigenic cells in vitro. Here we evaluate the effect of two different systemic MEMP treatment regimens (30 Hz, > 2T) on syngeneic MC38 colon adenocarcinoma subcutaneously engrafted in C57BL/6 mice. Tumor development was monitored by bioluminescence imaging, and excised tissues were evaluated for immune-cell infiltration (CD4, CD8, and CD68), oxidative stress (HO-1, MDA), and DNA damage (γH2AX) markers by immunohistochemistry. The MEMP regimes consistently and significantly slowed tumor progression and extended animal survival, with no detectable adverse effects on welfare. Histopathology revealed in treated tumors broader necrotic regions, signals of oxidative stress, and γH2AX staining showing limited yet evident DNA damage. While the number of intratumor CD4 and CD8 T-cell-counts remained stable, an apparent increase in the number CD68+ macrophages was noticed in the tumors of treated mice, suggesting that MEMP may enhance the penetration of immune effectors cells into the xenografted tumors, a preliminary evidence deserving further research. Further, MEMP achieved complete tumor regression in a small subset of animals, (n = 2), which mounted a robust resistance to a subsequent tumor re-challenge. Collectively, our findings indicate that systemic MEMP can alter tumor dynamics and immune features in pre-clinical animal models, offering a practical framework to study tumor–immune interactions at the organismal level under controlled physical-field conditions.