Effect of radiofrequency radiation exposure on mouse skin tumorigenesis initiated by 7,12-dimethybenz[alpha]anthracene.
OBJECTIVE
Although radiofrequency (RF) radiation is not considered mutagenic, it has been suggested as a promoter of tumorigenesis. To study if RF radiation has a tumor promoting effect, we exposed mice with skin tumorigenesis initiated by 7,12-dimethybenz[a]anthracene (DMBA) to RF radiation.


METHODS
Eighty male ICR mice were subjected to a single DMBA application (100 microg/100 microl acetone/mouse) on shaved dorsal skin at the age of 7 weeks. After one week, the mice were randomized into four equal groups of 20 mice each: i.e., sham-, 849 MHz-, 1,763 MHz-exposed, and 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated groups. The RF exposure was conducted at a whole body average specific absorption rate (SAR) of 0.4 W/Kg, for 2 cycles of 45 min exposure with a 15 min interval each day, 5 days a week for 19 weeks. The TPA-treated group served as a positive control for skin tumorigenesis and were administered TPA (4 microg/100 microl acetone/mouse) twice weekly without RF exposure.


RESULTS
All mice were examined weekly at a macroscopic level. No skin tumors were observed in any groups except in the TPA-treated positive control group. TPA is known tumor promoter in DMBA-induced skin carcinogenesis and tumor incidence in the TPA treated group was 95%. At week 20 after DMBA initiation, skin tissues were analyzed immunohistochemically using anti-proliferating cell nuclear antigen (PCNA) antibody. No differences were observed by pathological examination or by PCNA staining between the sham- and the RF-exposed groups. The expression of cyclin D1 and c-fos were detected only in the tumorous skin tissues of the TPA-treated group.


CONCLUSIONS
No evidence was found that RF radiation serves as a tumor promoter for skin tumors. Our data suggests that 849 MHz and 1,763 MHz RF radiations, similar to those emitted from mobile phones, do not have any promoting effect on skin tumor development in DMBA-initiated mice.
Huang
Tai-Qin
TQ
ILCHUN Molecular Medicine Institute MRC, and Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul.
Lee
Jae-Seon
JS
Kim
Tae-Hyung
TH
Pack
Jeong-Ki
JK
Jang
Ja-June
JJ
Seo
Jeong-Sun
JS
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000008:administration & dosage; D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage; D040421:Cell Phone; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009381:Neoplasms, Radiation-Induced / Q000503:physiopathology*; D011897:Random Allocation; D012878:Skin Neoplasms / Q000209:etiology*; D013755:Tetradecanoylphorbol Acetate / Q000008:administration & dosage
D002273:Carcinogens; D015127:9,10-Dimethyl-1,2-benzanthracene; D013755:Tetradecanoylphorbol Acetate