Cancers arise from the normal cells of an organism due to genetic mutations that cause uncontrolled growth and division of these cells.

Cancer cells share many similarities with the cells from which they originated, including their DNA, proteins, and overall structure. However, cancer cells have undergone genetic alterations that allow them to proliferate abnormally, invade surrounding tissues, and metastasize to distant sites in the body. These alterations can affect various genes involved in cell cycle regulation, growth factor signaling, DNA repair, and other cellular processes.

While cancer cells exhibit abnormal characteristics, they do not represent a new species in the traditional sense. They still belong to the same species as the organism from which they originated and are derived from the host's own genetic material. They do not possess the genetic distinctness or reproductive isolation required to be considered a separate species.