What is the medical prefix used for cancer?

The medical prefix associated with cancer is "onc/o." This prefix derives from the Greek word "onkos," which means mass or tumor. In medical terminology, "onc/o" is commonly used to form words related to tumors and cancer, such as oncology (the study and treatment of cancer) and oncologist (a doctor specializing in the diagnosis and treatment of cancer).

Understanding the role of "onc/o" is important, as it connects a variety of terms that revolve around the presence and treatment of tumors, whether benign or malignant. This prefix specifically denotes the aspect of cancer, making it the correct choice in this context.

The other options represent different medical concepts: "cyt/o" refers to cells, which is significant in various contexts including cellular composition; "malign/o" indicates a harmful or cancerous nature but is not a prefix in the same sense as "onc/o"; and "necr/o" involves death or necrosis of tissue rather than cancer specifically.