###Human: What are the consequences of not treating a tumor? ###Assistant: Hello. Tumor basically consists of cells with unregulated capacity to multiply and spread. So, if tumor is not removed, then its size keep on increasing. Also, it spreads to different organs through blood and other tissues, and occupies other organ as well. So, normal tissues or organ throughout the body is invaded by tumor cells which cannot carry out the normal function of the organ, so organ failure ensues. So, one organ failure leads to other and eventually heart stops and person dies. So, human body is invaded by cells which causes dysfunction in the body and eventually body stop working (means death) before going ahead. But, we cannot consider it as separate or new organism because new cells are not functional and cannot form organs to make a new organism. For imaginary purpose, you can think in a way you mentioned of transforming or replacing one individual with other or person who has acquired some new characteristics due to tumor cells, etc., but does not occur in reality.