The manuscript discusses a possible hypothesis about the transformation of healthy cells into cancer cells as a result of modification of the molecular structure of intracellular water from normal hexagonal to abnormal cubic phase (which may be caused by radiation, chemical, viral, mechanical and microbiological factors) and the possibility of returning to its original state under the influence of microwave radiation. The authors are not aware of any relevant experimental and theoretical support for this hypothesis in other literature.Our hypothesis is based on a completely unexpected experimental fact that we have received. It turned out that the radio spectra of cancer-affected tissues and the cubic phase of water are identical which confirms that these tissues really contain a cubic phase of water. It should be expected that the use of radiation of "therapeutic" frequencies may lead to regression of tumor growth. This assumption is based on another experimental fact confirming the possibility of the transition of the molecular structure of water from the cubic phase to the hexagonal phase (which is contained in healthy tissues) when irradiated with therapeutic frequencies.The conducted experiments demonstrate the real possibilities of structural-phase and spectral mutual transformations of the water medium under the influence of extremely low intensity flows of microwaves at "therapeutic" frequencies of 1000 MHz and 985 MHz or "pathologic" frequencies of 990 MHz and 51 GHz. The aim of this study was to experimentally verify a possible causal relationship between the violation of the molecular structure of intracellular water in healthy tissues and carcinogenesis.