> definitions of data.frames vs. matrix vs vectors. I have read many R. > tutorials, and looked over ump-teen 'cheat' sheets and have found that. > no one has articulated a really good definition of the differences. > between 'data.frames', 'matrix', and 'arrays' and even 'factors'.
Medical Definition of Tumor Our Tumor (Grade) Main Article provides a comprehensive look at the who, what, when and how of Tumor (Grade) Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow.
Cancer is a disease in which cells become abnormal and form more cells in an uncontrolled way. With breast cancer, the cancer begins in the tissues that make up the breasts. The cancerous cells may form a mass of tissue called a malignant tumor. The cells of a malignant tumor may spread to other parts of the body and threaten life. (Benign [buh-NYN] tumors are abnormal growths that are not cancer.