Cancer is mainly related to oncogene activation, loss of function of oncogenes, apoptosis disorders, etc. It is not infected through blood. 1. Oncogene activation: point mutations, gene amplification, chromosomal rearrangements, etc. will promote cell growth and lead to overexpression of specific gene products, thus leading to the occurrence of cancer. 2. Loss of function of tumor oncogenes: when the promoter of an oncogene is hypermethylated, it becomes dysfunctional and cannot fight against cancer genes. 3. Dysfunction of apoptosis-regulating genes: dysfunction of apoptosis genes and dysfunction of apoptosis pathways never lead to apoptosis resistance, thus contributing to the development of cancer. 4. Genomic instability: Many factors, such as alkylating agents, can cause DNA damage that never contributes to the development of cancer. Cancer occurs mainly because the genes inside the organism are damaged and altered. Wounds in contact with blood do not cause cancer.