What The Lack of EMF Research Really Means
The currently ongoing deployment of the fifth generation of the wireless communication technology (5G) is being met with a great enthusiasm by the telecommunication industry, national governments and portion of the general public. However, there is also some resistance from the part of the population in various locations around the globe.
The opposition towards the deployment of the 5G is caused by the uncertainty whether radiation emitted by the 5G networks and devices will have any effects on human health and environmental impact on fauna and flora.
The 5G wireless communication technology that is being deployed comprises of parts of the used already 3G and 4G technologies. The radiation emitted by the predecessors of the 5G, the radiation frequencies emitted by the 3G and 4G technologies, has been classified by the International Agency for Research on Cancer(IARC), as possible human carcinogen. The IARC evaluation did not concern the frequencies above 6 GHz, especially the currently prepared for use 26 and 28 GHz bands and the whole spectrum of 30–300 GHz frequencies that will be used in coming years. The currently deployed 5G will be supplemented with a new technology that uses the millimeter-waves (mm-waves) for the fast transfer of large amounts of data. Right now, the 5G technology expands into the frequencies below the 6 GHz. Later on, the 5G will use also the frequencies of 6–30 GHz and, still later on, frequencies of mm-waves (30–300 GHz). Currently, in Europe, the spectrum of 26 GHz (range 24.25–27.5 GHz) and 28 GHz (range 26.5–29.5 GHz), is being freed for the 5G use.
It is well established that the 26 and 28 GHz frequencies and mm-waves penetrate only few millimeters inside the human body and are efficiently absorbed by the water content of dermis layer of the skin. This fact has been used to misleadingly portray mm-waves as unlikely affecting the physiology and health of human body because the depth of penetration is only skin deep and does not reach any internal organs.
Do we know enough about the interactions between skin and skin cells with mm-waves to determine what health impact, if any, will have the acute and the long-term (life-time) exposure of skin to mm-waves?
In order to answer the question, literature search was performed to find studies where skin and skin cells were examined following exposure to mm-waves and affected functions and properties of skin and skin cells were evaluated in the context of the possible impact, or lack of it, on human health.
In this brief opinion review is presented evidence on the physiological effects of mm-waves exposures on human volunteers, on laboratory animals and on human and animal cells grown in the laboratory.
In the research examining the effects of mm-waves, skin is simplified into three major components, the stratum corneum consisting of mostly dead cells, the epidermis consisting of few layers of cells where the bottom layer is made of dividing cells that continuously regenerate the epidermis and the underlying dermis layer. The water content of the skin is what determines the depth of penetration of the mm-waves into human body, limiting it to just couple of millimeters.
From the point of view of water content of the skin, the top layer of the skin, the stratum corneum, has low water content 15–40%, whereas the water content the rest of the skin, epidermis and dermis, is ca. 70–80%. Thus, mm-waves energy penetrates the stratum corneum but is efficiently and effectively absorbed by the water in epidermis and dermis layers .
Skin is the largest organ of human body that not only functions as kind of “overcoat” but is involved in regulation of physiological processes that impact the functioning of the whole body.
Skin has different thickness, color, and texture in different locations over the body and performs number of important functions. Skin (i) regulates immune response by both mechanically preventing entry of microorganisms and biochemically by generation of molecular mediators that are distributed with blood circulation to internal organs (ii) regulates body temperature, (ii) stores water and fat and prevents water loss, (iii) functions as sensory organ, and (vii) helps to make vitamin D when exposed to the sunlight.
Skin is composed of a variety of cell types that perform various functions. In epidermis reside keratinocytes, melanocytes, Merkel cells, and Langerhans cells. The dermis consists of connective tissue cells and extracellular matrix and there are located numerous nerve endings that provide the sense of touch and heat, the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. Furthermore, the skin surface provides an environment for over thousand identified species of microbes.
Different pathological conditions affecting skin might have impact on how the skin and skin cells perform their functions and how they might react/respond to mm-waves exposure. These skin ailments, that will affect levels of water in the skin, include dermatitis, eczema, psoriasis, dandruff, acne, cellulitis, skin abscess (boil or furuncle), rosacea, warts, melanoma, basal cell carcinoma, seborrheic keratosis, actinic keratosis, squamous cell carcinoma, herpes blisters, hives, tinea versicolor, viral exantham, shingles, herpes zoster, scabies, or ringworm .
Therefore, skin is not just a thin overcoat on the surface of the human body but it is an aggregate of numerous cells and microorganisms living together and playing a crucial role in regulating of the health and wellbeing of human body. As Sanford and Gallo  pointed out in their review article:
“…The skin, the human body’s largest organ, is home to a diverse and complex variety of innate and adaptive immune functions […] the skin immune system should be considered a collective mixture of elements from the host and microbes acting in a mutualistic relationship…”
Human cells in vitro studies
The above table lists human in vitro studies. There are some 26 studies that examined effects of mm-waves on human skin-residing cells such as: buccal cells, fibroblasts, glial cells, primary keratinocytes and keratinocyte cell line, lymphocytes and melanoma cells. Results obtained by different research groups vary, showing both, some effects or lack of effects of (MMW) exposure.
Shckorbatow et al. ,  have observed changes in chromatin condensation that may suggest effect on activity of genes and on gene transcription process
Shckorbatow et al.  observed an increase in granularity of the chromatin in fibroblasts, occurring in a radiation dose dependent manner. Furthermore, the effect was radiation polarization-dependent, where right-handed polarization had stronger effect than the left-hand polarization.
On the other hand, Yakeshiwa et al.  has shown lack of effects on proliferation and toxicity of fibroblasts.
Also Gallerano et al.  have shown lack of effects on a variety of cytogenetic markers in fibroblasts.
Nicolaz et al. and Zhadobov et al.  have shown lack of effect on cellular stress markers and on protein folding, secretion and maturation in endoplasmic reticulum.
Primary cultures of keratinocytes
Bourne et al.  did not detect any effect on stress response by monitoring expression of glutathione and Hsp70.
Le Quement et al.  analyzed expression of 41,000 genes using microarray assay. Depending on the statistical analysis applied to the data, the result was either no effect at all (Benjamini-Hochberg procedure) or effect on some 130 transcripts (t-test). Further analysis of these t-test-indicated potentially affected transcripts by RT-PCR has shown that 24 proteins were indeed affected by the MMW exposure. This observation points out that some of the statistical analyses may incorrectly dismiss changes in expression of genes, especially when the changes are small in magnitude.
Habauzit et al.  observed an effect on gene expression that, according to the authors, suggests a specific electromagnetic effect of mm-waves as the effects was not possible to mimic solely by altering temperature of the cells.
Soubere Mahmoud et al. , similarly to Habauzit et al. , also did not observe any direct effect of MMW exposure on the transcriptome. However, they observed that mm-waves exposure might affect cells that are under metabolic stress.
Keratinocyte cell line HaCaT
Chen et al.  observed lack of effect of MMW exposure on cell-cell communication via gap junctions. However, mm-waves exposures appeared to reverse suppression of gap junction communication induced by phorbol ester. Similarly, lack of effect on gap junction communication was observed by Szabo et al. .
Szabo et al. ,  observed lack of exposure on cell viability, proliferation, adhesion, chemotaxis, interleukin production, expression of stress protein Hsp70. Similarly, Zhadobov et al.  did not observe effect of MMW exposure on cell proliferation, gene expression of the conformation of proteins.
Using HaCaT keratinocytes as well as mouse melanoma cells B16F10 and Jurkat cells, Szabo et al.  observed the mm-waves-exposure-induced externalization of phosphatydylserine residues on cell membranes, occurring without visible cell membrane damage. Expression of phosphatydyl serine, an early marker of apoptosis, in combination with the observed lack of damage to cell membrane, suggests that biological processes induced by mm-waves exposures could be initiated by the molecular changes induced in cell membranes. Similarly, Le Pogam et al.  have observed effect of mm-waves exposures on the permeability of cell membranes.
Le Quement et al.  have shown that while mm-waves exposure does not induce endoplasmic reticulum stress markers of BIP and ORP150, it is able to prevent expression of these markers that was induced by thapsigargin. This points out to potential co-exposure effects of mm-waves exposures.
An important marker of the potentially detrimental effect of radiation exposure is a damage to chromosomes and chromatin. Hintzsche et al.  examined effects of mm-waves exposure on DNA strand breaks and presence of micronuclei and observed lack of an effect.
Using primary dividing lymphocytes, Korenstein-Ilan et al.  observed mm-waves-exposure-induced changes in several chromosomes number and replication and suggested that exposures induce genomic instability, a cancer risk factor.
Beneducci et al.  using stable leukemia cell line have observed very extensive changes in leukaemia cell morphology and in glucose metabolism.
In two separate studies by Beneduci et al. , , the effects of mm-waves exposure differed from each other. Using the same melanoma cell line RPMI 7932, in the first study, there was observed an anti-proliferative effect of mm-waves exposure whereas in the second study mm-waves exposure did not affect cell proliferation or cell cycle distribution of cells.
In conclusion, there is an urgent need for research on the biological and health effects of mm-waves because, using the currently available evidence on skin effects, the claims that “we know skin and human health will not be affected” as well as the claims that “we know skin and human health will be affected” are premature assumptions that lack sufficient scientific basis.