肿瘤的发生是基因突变逐渐积累的结果（1）癌细胞的出现一般都要有 5～6

The occurrence of tumors is the result of the gradual accumulation of gene mutations <br>(1) The emergence of cancer cells generally requires 5 to 6 gene mutations. <br>(2) The mutation of the proto-oncogene does not immediately form cancer, but continues to grow until there is a new gene mutation. <br>(3) There are two copies of tumor suppressor genes, both of which are lost or inactivated to make the cell cancerous; and as long as one gene of the two copies of the proto-oncogene is mutated, it may become cancerous.

The occurrence of tumor is the result of gradual accumulation of gene mutations<br>(1) Cancer cells usually have 5 ~ 6 gene mutations.<br>(2) Mutations in proto oncogenes do not immediately form cancer, but continue to grow until there are new gene mutations.<br>(3) There are two copies of tumor suppressor genes, and only when they are lost or inactivated can the cell become cancerous, while only one gene in the two copies of proto oncogene mutates, it may become cancerous.

The occurrence of tumor is the result of gradual accumulation of gene mutation. (1) The emergence of cancer cells generally requires 5 ~ 6 gene mutations. (2) The mutation of proto-oncogene will not form cancer immediately, but will continue to grow until there is a new gene mutation. (3) There are two copies of tumor suppressor genes, and only when they are lost or inactivated can cells become cancerous. However, if only one gene in two copies of proto-oncogene is mutated, it may become cancerous.