Tumorigenesis is the formation of tumors in the body, often caused by oncogenes. These tumors are the result of uncontrollable reproduction (cell division) due to alterations in the cell‘s genetic code, creating lesions in the tissue where they reside.

Tumorigenesis can be divided into tumor initiation, promotion and progression.

Oncogenomics often studies tumors caused by such a condition in hope of pinpointing genes – pieces of genetic information – that are susceptible to being changed (mutated) by external factors like ultraviolet light, toxic chemicals, and other carcinogens. The range of normal genetic alterations that a person’s DNA undergoes over time is extraordinarily large, so it is hard to detect exactly what cause tumorigenesis.

Tumorigenesis is a symptom of cancer.