## 1 Introduction  
Treatment of different types of cancer, specifically in metastatic stages is a major challenge in oncology. Major limitations stem from the small number of therapeutic agents that are specific with minimal side effects and capable of long-term control of tumor growth. Lung cancer is considered one of the most deadly types of cancer for humans and is often diagnosed in a late incurable stage [1, 2]. The vast majority of lung cancers are derived from epithelial cell carcinomas. The two main types are small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), for which there are different treatment paradigms and expected survival outcomes. About 85% to 90% of lung cancers are NSCLC. Three main subtypes of NSCLC exist differing in size, shape, and chemical make-up [3]. Lung adenocarcinoma, an epithelial cancer of glandular origin, is the most prevalent of lung cancer diagnoses. Standard cytotoxic chemotherapy is effective in certain cases with majority of the available treatments offering only a limited survival benefit [4]. Metastasis is a multistep process and the main cause of mortality in lung cancer patients. The survival prognosis of lung cancer patients without treatment is very poor with a mortality rate of 98% [5]. To date, no effective methods for early diagnosis and treatment of lung cancer have been developed. The interaction of biological cells with electromagnetic (EM) waves has been under investigation for several decades and non-thermal cytological effects of irradiation intensively studied [6]. In recent years there has been a growing interest in millimeter wave (MMW) irradiation as a possible treatment for cancer. MMW with frequencies within 30-300 GHz cause biophysical effects without significantly increasing the temperature of the cells [7]. MMW penetration depth of biological tissue is a few millimeters only due to high absorption by water molecules. Experimental reports suggest MMW radiation likely affects information-carrying signals guiding internal processes in cells thereby affecting the whole organism. Illustratively, MMW irradiation within 40.5-51.8 GHz leads to biological activation of free nerve endings in the skin [8; 9; 10]. The central nervous system modulates neural activity resulting in the development of various biological effects, such as the release of endogenous opioids. The biochemical regulatory links of neuronal opioids of the local pulmonary opioid network affect human lung cancer cell proliferation [11; 12]. Further, endogenous opioids are reported to be involved in suppression of melanoma growth by MMWs [13]. Reversible morphological and ultrastructural alterations in erythromycinpoloid leukemia, melanoma and breast cancer cell lines by 53-78 GHz MMW irradiation under 1 uW/cm\({}^{2}\)[14; 15; 16] demonstrated the anticancer treatment potential of this therapy. The effects were associated with a significant inhibition of cell proliferation correlated to structural membrane changes and energy metabolism modification of the exposed cells. In contrast, low power MMW exposure at 60.42 GHz and 1 mW/cm\({}^{2}\) did not show any significant effects on the proliferation of multiple human cell lines [17]. These results suggest that the anti-cancer properties of MMW are directly dependent on irradiation parameters and/or the selective response of different cell types. For instance, an indirect influence of MMW exposure at 42.2 GHz and 36.5 mW/cm\({}^{2}\) led to a decrease in tumor metastasis through activation of natural killer cells [18]. To date, the mechanism of MMW interaction with cells challenges research efforts. Most previous studies were done with discreet frequencies and/or in pulsed regimes of irradiation with very few of them involving a wide frequency spectrum. We reported cytotoxic effect of W-band (75-105 GHz) MMW corresponding to wavelengths (\(\lambda\)) = 4-2.73 mm based on morphological changes of H1299 human lung cancer cells [19].