Based on case-control studies there is a consistent finding of increased risk for glioma and acoustic neuroma associated with use of mobile phones. Similar results are found for cordless phones in the Hardell group studies. These results are supported by the results in the NTP animal study (https://ntp.niehs.nih.gov/ntp/about_ntp/trpanel/2018/march/tr595peerdraft.pdf, https://ntp.niehs.nih.gov/ntp/about_ntp/trpanel/2018/march/tr596peerdraft.pdf). Malignant vestibular schwannoma is a similar tumor type as acoustic neuroma, also called vestibular schwannoma.
The findings are less consistent for meningioma although somewhat increased risk was seen in the meta-analysis of ipsilateral mobile phone use. A longer follow-up time is necessary for this type of slow growing tumor.
The results on glioma and acoustic neuroma are supported by results from other animal studies showing co-carcinogenic and tumor promoting effects from RF radiation (Tillman et al 2010, Lerchl et al 2015). The NTP study showed genotoxicity of RF radiation in rats and mice exposed to RF radiation (Smith-Roe et al 2017) and now presented in more detail. That result supports previous findings of DNA strand breaks in rat brain cells exposed to RF radiation (Lai, Singh 1997).
One mechanism in carcinogenesis could be oxidative stress with production of reactive oxygen species (ROS) as summarised by Yakymenko et al (2016). This could be an indirect mechanism for the increased brain and head tumor risk (Megha et al 2015) since ROS may give DNA damage.
By now carcinogenicity has been shown in human epidemiological studies replicated in animal studies. Laboratory studies on RF radiation have shown increased ROS production that can cause DNA strand brakes. We published in 2013 the conclusion that RF radiation should be regarded as a human carcinogen Group 1 according to IARC definition, based on scientific evidence (Hardell, Carlberg 2013b) further supported in our up-dated article (Carlberg, Hardell 2017). That conclusion is reinforced by the current evaluation.