Evidence for microwave carcinogenesis in vitro.

Abstract

We investigated the carcinogenic activity of 2.45 GHz microwave radiation (MW) combined with benzo[a]pyrene (BP) or X-rays, using an in vitro assay for malignant transformation in C3H/10T1/2 mouse-embryo fibroblasts. Additional experiments were performed to assess the effect of a non-cytotoxic and non-transforming concentration of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) on transformation induction in cells treated with MW and X-rays. Experiments were performed at low incident power density, corresponding to an energy absorption rate of 4.4 W/kg. Cells were treated at 37.2+/-0.1 degree C. MW reduced the plating efficiency of 50%, while TPA increased it by 40%. MW had no effect on transformation induced by BP or X-rays in the absence of tumor promoter. TPA treatment of cells previously irradiated with MW and X-rays yielded a statistically significant 3.5- or 1.6-fold increase in transformation when compared with the transformation frequency of cells previously irradiated with X-rays alone at 1.5 and 4.5 Gy, respectively. Our results suggest that low-level 2.45 GHz MW radiation can induce latent transformation damage which can then be revealed by the action of tumor promoters.

AI evidence extraction

Main findings

At low incident power density (energy absorption rate 4.4 W/kg) and controlled temperature (37.2±0.1°C), 2.45 GHz microwave radiation reduced plating efficiency by 50%. Microwave exposure had no effect on transformation induced by benzo[a]pyrene or X-rays in the absence of tumor promoter, but subsequent treatment with a non-cytotoxic/non-transforming concentration of TPA after microwave and X-ray exposure produced statistically significant increases in transformation compared with X-rays alone (3.5-fold at 1.5 Gy; 1.6-fold at 4.5 Gy).

Outcomes measured

• malignant transformation frequency (in vitro assay)
• plating efficiency

Limitations

• Sample size not reported in abstract.
• Exposure duration not reported in abstract.
• In vitro model; generalizability to in vivo/humans not addressed in abstract.
• Microwave-only effect on transformation is not clearly quantified in abstract (focus is on interaction with TPA and X-rays).

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": 4.4000000000000003552713678800500929355621337890625,
        "duration": null
    },
    "population": "C3H/10T1/2 mouse-embryo fibroblasts (in vitro)",
    "sample_size": null,
    "outcomes": [
        "malignant transformation frequency (in vitro assay)",
        "plating efficiency"
    ],
    "main_findings": "At low incident power density (energy absorption rate 4.4 W/kg) and controlled temperature (37.2±0.1°C), 2.45 GHz microwave radiation reduced plating efficiency by 50%. Microwave exposure had no effect on transformation induced by benzo[a]pyrene or X-rays in the absence of tumor promoter, but subsequent treatment with a non-cytotoxic/non-transforming concentration of TPA after microwave and X-ray exposure produced statistically significant increases in transformation compared with X-rays alone (3.5-fold at 1.5 Gy; 1.6-fold at 4.5 Gy).",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract.",
        "Exposure duration not reported in abstract.",
        "In vitro model; generalizability to in vivo/humans not addressed in abstract.",
        "Microwave-only effect on transformation is not clearly quantified in abstract (focus is on interaction with TPA and X-rays)."
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2.45 GHz",
        "microwave radiation",
        "SAR 4.4 W/kg",
        "in vitro",
        "C3H/10T1/2",
        "malignant transformation",
        "benzo[a]pyrene",
        "X-rays",
        "TPA",
        "tumor promoter",
        "plating efficiency"
    ],
    "suggested_hubs": []
}

Comments

Log in to comment.

No comments yet.