1. What is a tumor? Tumor, unlike many other diseases (such as inflammation, trauma, etc.), is a new tissue formed by abnormal proliferation of some tissue cells in the body due to special causes. Usually, tumors are divided into benign tumors and malignant tumors. Benign tumors are not discussed because they are benign in nature and often coexist with the organism and do not produce great physiological changes. Malignant tumors, notorious for their abnormally rapid (malignant) cell proliferation, as well as their frequent invasion and metastasis, become health-threatening killers. 2. How do tumors come about? This is the etiology of tumor, simply put, it is “genetic mutation”! Such mutations include: ① activation of “proto-oncogene” (i.e. cancer producing), just like the devil being released from the magic lamp; ② inactivation of “oncogene” (i.e. cancer suppressing), just like the firewall failing and the computer being invaded by virus. ③Specific factor changes, such as telomerase, which is an important signaling molecule in the cell replication process, and changes in telomerase can cause differences in the DNA replication process, just as ink will lose color when printed repeatedly. ④Environmental factors: such as environmental carcinogens, which always remind people of “haze causes lung cancer”, and ultraviolet light, like sunlight causes malignant melanoma. Although these statements are not accurate, they are helpful for people to understand. 3. Can tumors be hereditary? Since it is said above that tumor is a genetic mutation and we know that genes are passed from generation to generation, isn’t it true that tumor will be inherited? Answer: Of course not! Generally speaking, most of the tumors (more than 90%) are not hereditary, about 5% of the tumors are hereditary, but some of them (such as breast cancer, colorectal cancer, kidney cancer, etc.) have the tendency to run in families. ①Why are tumors not hereditary? As we all know, heredity means “a dragon gives birth to a dragon, a phoenix gives birth to a phoenix, and a mouse’s son loves to make a hole”. For a tumor patient, as long as the tumor does not occur in germ cells (the incidence of tumor in germ cells is very low), then the germ cells are normal and the offspring developed from normal germ cells are of course normal. ②How to understand the genetic characteristics of tumors? The family inheritance of tumor was previously thought to be caused by chromosomal aberrations, which are sometimes passed on to offspring, but this inheritance is not a direct tumor inheritance, but only a genetic predisposition and more susceptibility. And the so-called susceptibility of tumor inheritance refers to the fact that under the same conditions, some people are more sensitive to external stimuli and more likely to develop tumor. For example, when the immune function of the body is low, the mutated cells cannot be eliminated at the primary stage in time, leading to the occurrence of tumor. Therefore, people with family history of tumor should pay attention to maintain a healthy lifestyle. ③What is hereditary tumor syndrome? A series of diseases that occur due to genetic factors acting on tumors are most obviously manifested as hereditary tumor syndrome. It is called hereditary tumor syndrome because of hereditary causes of chromosomal and genetic abnormalities, especially autosomes and genes on them, which greatly increase the chance of developing certain tumors. There are autosomal dominant hereditary tumor syndromes, such as familial retinoblastoma, and autosomal recessive hereditary tumor syndromes.