Overview of Hematopoietic Stem Cells in Systemic Cancer Treatment, Aging, Pregnancy, and Radiation Hormesis

Abstract

Background: The unavoidable links between the benefits of conventional systemic treatment of cancer and the side effects such as lymphopenia. Objective: To analyze this phenomenon in view of the newly discovered trophic function of circulating hematopoietic stem cells (HSC) and their lymphocyte descendants. Method: We used population statistics and recent current research involving natural aging and preliminary aging with cancer, its cytotoxic therapy, eclampsia at pregnancy, and radiation hormesis. Results: In contrast to immune-defense interpretations of these health conditions, the trophic influence of HSC and morphogenic lymphocytes on natural tissue renewal and regeneration after sublethal injuries eliminates the majority of covered inconsistencies, which are inherent to the dominating idea of cellular immunity. Conclusion: Our examination led to the feeding influence of lymphopoiesis on tumor progression, an indirect mechanism of tumor growth control by systemic therapy via either destruction of trophic cells, or by competitive distraction from malignant tissue via reparation of sublethal injuries in normal tissues. Analyses also involved similarities of the mechanisms of systemic chemotherapy and total body/half body radiotherapy in low doses, as well as the futility of the theoretical opposition of the radiation hormesis phenomenon to the linear non-threshold model, dominant in radiobiology.