Abstract
The change of the entropy is the arrow of understanding spontaneous processes in complex systems. The entropy production is the sum of several entropy flows resulting in collective entropy, which determines the direction of individual entropy flows in a biological system. In case of cancer patients these thermodynamical terms have a key role in the tumor development on the expense of the host integrity. The life develops towards the entropy minimum, but cancer tends towards entropy maximum. The relationship between entropy and information quantity was discussed in general by Schrödinger in 1948 and Prigogine [1, 2]. Thermodynamic differences between solid tumors and surrounding normal tissues were promising objects to follow the direction of entropy flow between normal and cancerous tissues. Cancer development is an exergonic process, heat flows from tumor to its surroundings forcing to surrounding normal tissues to gain heat. The differences in the fluxes of entropy produced by various components define the interaction and direction of entropy flow between tumorous and healthy tissues. Tumor cells always have higher entropy than normal cells. Normal, healthy cells develop toward the entropy minimum, whereas the entropy production of cancer cells proceeds towards the entropy maximum. Entropy production rate is the result of bidirectional currents, the sum of individual fluxes flowing in opposite directions between cancerous and normal tissues in the open system. The irreversible processes communicated via various dissipation mechanisms are driven by differences in heat production, chemical potential gradients, Gibbs energy, intracellular acidity, conductance, membrane potential gradients, membrane potential of cells and the response to the exposure to external force fields. The rate of entropy production of tumors is always higher than that of healthy tissues. The response in entropy production of normal and tumorous tissues to applied external forces is different. Consequently, the exposure of a tumorous area to external energy may reverse the direction of the entropy-current-mediated flow of information between the tumor and its environment. In this paper the differences between normal and cancerous tissues will be analyzed on the basis of a comparison of the direction of various components of entropy flow. When the entropy production of the normal tissues is increased by a particular external force so as to be above the entropy of the cancerous tissues, the newly achieved higher entropy of the healthy tissue mediates the signal transmission of normal tissue- to the cancer cells. The process can lead to possible new strategies in the therapy of solid tumors. The expansion of the tumor mass into normal tissues in an intimate relationship provides certain advantages as concerns the survival and growth for normal tissues over that of tumorous tissues. In this process the following mechanisms should be considered: the modification of energy production, glucose oxidation, pH, and the membrane potentials by means of external forces etc. It is presumed that some type of external forces can reduce the entropy flow as a carrier of information flow from cancerous tissues to normal tissues. We suppose that the second law of thermodynamics allows to change the direction of informational entropy from co-existing tumorous tissues to normal tissues by specific external forces. The direction of some components of entropy flow can be reversed. Thermodynamics is essential for an understanding of the processes maintaining the living state and conditions resulting in weak links in biological processes, leading to various diseases. The mechanism of cancer development may involve a thermodynamic explanation, where a series of effects induce disorder in healthy tissues. The process is characterized by the conversion of order to chaos in the exposed tissues that survive as a parasite of the host. Differences between development of healthy and tumorous tissues result in an unidirectional-way for the tumor growth, which evolve towards the entropy maximum following the second law of thermodynamics. Our paper will focus on aspects of and entropy production-related information flow in tumorigenesis and driving forces for cancer growth in the host. We suggest that the results of a thermodynamic comparison of tumor progression and conditions of sustaining healthy tissues will help in the design of novel strategies for cancer therapies.
Keywords: Chemical reactions, external force differences, Gibbs energy, healthy and tumor tissues, thermogenesis, viscous stress.