This study describes a novel model of cancer. Cancer is caused, according to this model, by two toxic molecules, COF 2 (carbonyl fluoride) and CS 2 (carbon disulfide). COF 2 acts as a catalyst and produces CS 2 . CS 2 acts as a catalyst and produces COF 2 . Hence, the molecules COF 2 and CS 2 have the ability to reproduce each other, i.e. to create a chain reaction where COF 2 and CS 2 are multiplied. COF 2 and CS 2 are toxic. It is proposed that long-term cell exposure to COF 2 and CS 2 may disturb cell apoptosis and cause uncontrolled cell growth, i.e. cancer. Consequently, cancer is caused by a disease causing mechanism or agent and not by a pathogen. However, cancer can be initiated by e.g. a bacteria or virus that contains the molecules COF 2 and CS 2 , wherein these molecules start a chain reaction producing COF 2 and CS 2 in the infected area and where the result can be cancer. The study describes why Fe 2 O 3 (iron (III) oxide) may have a therapeutic effect on cancer.