Non-ionizing radiation and cancer: A review on current evidence, mechanistic insights, and public health implications

Non-ionizing radiation (NIR) generated from the high power transmission lines, broadcasting antennas and cellular phones represent one of the widespread environmental exposures which can induce carcinogenic outcome. Although NIR lacks sufficient energy to dislodge the electrons for ionization, an indirect mechanism has been proposed to be involved in adverse outcomes under certain exposure conditions. Consequently, radiofrequency electromagnetic field (RF-EMF) exposure remains a consistent scientific and public health concern regarding its possible role in cancer manifestation. This review aims to analyze the findings of RF-EMF exposure and carcinogenicity by integrating epidemiological studies and experimental findings to demonstrate its potential function in cancer manifestation.The available evidence is not sufficient to conclude that RF-EMF exposure is a direct-acting genotoxic carcinogen or cancer initiator. However, laboratory studies have indicated that long-term exposure to non-thermal RF-EMF can cause oxidative stress, genomic instability, epigenetic alterations, ion transport disruption and dysregulation of cell-signaling pathways. These biological effects may contribute to the promotion and progression stages of carcinogenesis, but are not directly responsible for tumor/cancer initiation. The epidemiological evidence significantly varies between extremely low-frequency magnetic fields (ELF-MF) and radiofrequency electromagnetic fields (RF-EMF). Although ELF-MF exposure has demonstrated a more reliable association with childhood leukemia, the data connecting RF-EMF exposure to cancer is less consistent.Studies with the larger sample size and increased exposure duration are needed to strongly corroborate its involvement in cancer development.