tumorudviklingen

Tumorudvikling, also known as tumorigenesis or carcinogenesis, refers to the process by which normal cells transform into cancerous cells. This transformation is a complex, multi-step phenomenon driven by accumulated genetic and epigenetic alterations. These changes can affect genes that regulate cell growth, division, and death, leading to uncontrolled proliferation and the formation of a tumor.

The initial stages of tumor development often involve mutations in proto-oncogenes, which promote cell growth, or tumor suppressor genes, which normally inhibit it. When these genes are mutated, they can become oncogenes that drive excessive cell division, or the protective function of tumor suppressor genes can be lost. Environmental factors, such as exposure to carcinogens like tobacco smoke, UV radiation, or certain viruses, can initiate these mutations. Lifestyle factors, including diet and obesity, also play a role.

As a tumor grows, it requires a blood supply to obtain nutrients and oxygen, a process called angiogenesis. Cancer cells can also invade surrounding tissues and spread to distant parts of the body through metastasis. This spread is a hallmark of malignant tumors and is responsible for the majority of cancer-related deaths. The progression from a normal cell to a fully malignant tumor is a gradual process, often taking many years, and involves a series of accumulating genetic changes that confer progressively more aggressive characteristics to the cells. Understanding tumorudvikling is crucial for developing effective cancer prevention strategies and treatments.