This book delves into the intricate pathogenesis of cancer, focusing on the primary mutations of nuclear DNA in precursor cells. By examining the functional abilities of cancer cells and the pathological conditions that foster their development, the author theorizes on the identity of precursor cells. With keywords such as initiation, promotion, monocyte, malignant stem cell, and mutation, the reader is guided through the multi-stage mechanism of carcinogenesis. Exploring the cytogenesis of solid tumors and drawing parallels with hemoblastoses, the author sheds light on the etiology and pathogenesis of malignant diseases.