Human life is a complex system composed of countless chemical reactions. Every breath, every heartbeat, and even every act of thinking depends on precise operations at the molecular level. All life processes are chemical reactions; all enzyme activity follows reaction kinetics; all signaling pathways are molecular interactions. Cancer, a high-incidence disease in modern society, is likewise—in essence—the result of chemical reactions falling out of balance.Yet in conventional medicine, understanding of cancer largely remains at the level of genetic mutations, tissue pathology, or clinical treatment. It is often broken into countless fragments for study, while relatively few attempt a systematic explanation from its chemical nature. Chemistry is the foundational discipline underlying medicine and the life sciences. As a foundational discipline, chemical theory is often clearer and more straightforward than medicine or biology, and it helps avoid the difficulty of reducing cancer into gene-centered fragments that are hard to integrate and understand. This book aims to fill that gap: grounded in the theory of long-term imbalance of chemical reactions within the human body, and using free radicals as the point of entry, it explains the logic of cancer's emergence, progression, and prevention from the molecular and metabolic perspectives.The goal of this book is to provide readers with a scientific, actionable viewpoint. Readers will understand how free radicals are generated in the body, how they are cleared, and how they relate—often in highly intricate ways—to cancer. More importantly, readers will learn how, in everyday life, reasonable metabolic regulation, nutrition, exercise, and lifestyle choices can reduce the risks brought about by uncontrolled free-radical activity.Knowledge and information matter—but the capacity for judgment built on top of them matters even more. I hope that both medical professionals and general readers interested in life and health will find inspiration here. Understanding the chemical logic of life is not only a key to understanding cancer; it is also a form of scientific wisdom for taking charge of health, slowing aging, and optimizing life.This book does not claim that free radicals are the only variable. Rather, free radicals are chosen because they possess three properties that other variables rarely share simultaneously: (1) nearly all known carcinogenic factors converge, at the chemical level, into abnormalities involving free radicals; (2) free radicals directly participate in covalent damage to DNA, proteins, and lipids—they are "e;executors of reactions,"e; not merely downstream markers; and (3) free-radical levels are measurable and intervenable, allowing theory to connect with practice. For these reasons, free radicals serve as the "e;intersection point"e; of this book—a methodological choice, not an exclusive assertion.Chapters 1 and 2 introduce the chemical properties of free radicals and their mechanisms in carcinogenesis. Chapters 3 and 4 explain how free radicals can account for the nine hallmarks of cancer and for all known carcinogenic factors. Chapter 5 discusses how to regulate free radicals through multiple pathways for cancer prevention and treatment. However, because metabolic computation in the human body is not yet fully developed, the realistic and feasible path still begins with lifestyle: replenishing essential nutrients, reducing toxic exposures, and lowering excessive free-radical burden. The methods described here are not esoteric—they are understandable, testable, and practicable for ordinary people.The viewpoints in this book arise from long-term observation of real cancer patients. Some patients, after diagnosis, achieved better-than-expected control during treatment through information integration and simple interventions. Practice itself is among the most powerful forms of evidence in medicine and chemistry.
