Tumor , from the Latin for swollen, was first used in 1597. A tumor is an abnormal proliferation of cells not caused by infection or inflammation. Malignant tumors are rapidly growing, not well-localized, invasive, cannot be recognized for their tissue of origin, and readily spread through blood, lymph or compression to other locations in the body. Many tumor cells lose any physiologic purpose, but some tumor cells retain the function of the original tissue of origin. A carcinogen is any agent capable of causing cancer.
Oncology is the study of cancer as performed by oncologists .
As our understanding of cancer clarifies and expands it is becoming apparent that this disease is dependent upon genetic factors, the immune status of the animal, viruses, trauma, radiation, hormones, chemicals, nutrition and various combinations of causative agents. Now that we have briefly defined our terminology, let us examine the incidence and types of tumors seen by veterinarians in captive reptiles. Be wary of such sweeping and unsubstantiated generalizations. The last fifteen years have produced an astonishing body of documentation of both the appearance and the incidence of tumors in reptiles. Thus, a wide variety of both benign and malignant tumors have been shown to occur in lizards, turtles and snakes.