How does the tumor form?

Tumor formation is a very complex process, its factors are also diverse, but in general, it is divided into two reasons, the first is external, the second is internal. External factors include what? The air we breathe, the water we drink, the things we eat, if unclean, or more polluted, and the tumor is obviously related. Internal factors include many kinds of situations: 1, the first is our mood, some people love sulking, some people emotional instability every day. 2, in addition to hormone problems, some people hormone secretion imbalance, such as obesity, is a very important factor in breast cancer. 3, some people will show Helicobacter pylori feeling or show papilloma virus, hepatitis virus infection, which are very important factors leading to cancer. Therefore, the causes of tumor formation are very complex, but the combination of external factors and internal factors, long-term inflammation and chronic infection of viruses are jointly caused.