Cancer, also termed malignancy is a disease characterized by an uncontrolled growth of cells, i.e., an abnormal growth of immortal cells with no apoptosis. More than 100 types of cancer are known, including breast cancer, skin cancer, colon cancer, prostate cancer, and lymphoma. What makes a cell a cancered one is the autointracellular pathogenic genome, or “cancerous genome” resulted from pathogenic mutation and located inside that cancered cell. The code of design of constructing or building the body of every species of all genomic-things is found in its genome; the same is true with the pathogenic genome in building the body of cancered cells (host cells). Three major types of tumor suppressor genes are known to code for proteins that suppress growth of cells: (i) one type tells cells to slow down and stop dividing, (ii) the second type is responsible for fixing changes (repairing) in damaged cells, and (iii) the third type is in charge of apoptosis (the programmed death of cell). If mutations that can inactivate any of these tumor suppressor genes occur, cancer will be onset and allow cancered cells to grow unchecked. The cytotoxic T cells and NK cells are 100% correct in identifying the cancered cell foreign to the body of the patient just as they identify viral genome-infected cells, because the genome inside the cancered cell is foreign to the body of the patient as it is transformed into a completely different genome from those found in the body of patient. The genome is transformed by a multitude of mutations referred to as driver mutations/pathogenic mutations. The transformed genome is said pathogenic because it causes the dangerous disease called cancer. As the genome is changed or transformed all biological molecules/biomass of its cells produced by the coded information or directives of this changed genome are foreign (nonself) to the body of the patient and that is why the killer immune cells recognize the cancered cell as foreign to the body of the patient and kill it. Unlike the genomes of the normal cells in the body of the patient, the changed genome makes the cancered cells immortal, promotes uncontrolled rapid cell divisions, metastatic growth of cancered cells and bans apoptosis. Thus, the genome transformed by pathogenic mutations is an autointracellular pathogenic genome. The scientific truth and the terrifying danger we suffer from cancer imparted by the term cancerous cell or cancer cell is erroneous, unpulverized, unfit or turbid, being targetless so that it cannot be used in academic lessons for learners/readers and as the result of this incompatibility it has been misleading students and confusing scientists of biological sciences of the world for centuries until the emergence of this paper. Therefore, using cancerous cell or cancer cell as a term in modern textbooks, articles of journals and in any scientific work must be banned completely. Whenever there is a patient of cancer, the host cell infected and the pathogen that invaded are the cancered cell (host cell infected) and autointracellular pathogenic genome (cancerous genome) respectively. The outcome of this study is strongly believed to empower researchers of cancer and health professionals to devise effective and optional methods of choice or strategies in fighting against cancer because their consciousness about cancer will be free from beating around the bush as the host and its intracellular pathogen that are essential for the occurrence of cancer are spectacularly distinguished to get the target accurately.