TABLE OF CONTENTS Cancer is indicative of a class of diseases which are characterized by uncontrolled division of cells. For division of cells to be called as cancerous, the cells produced as a result of the division must invade other tissues. This invasion can be in the form of direct growth into the adjacent tissues. This invasion can also be a result of implantation of these diseased cells from a source located at some distant site, this process is known as metastasis. Initially uncontrolled growth starts at a specific site; this is called in-situ growth or primary growth. Next the growth invades the neighboring tissues and some of the diseased cells get dislodged from the original site, travel through the bloodstream or lymphatic system and get lodged at other sites where a secondary growth commences. Secondary growth can take place at multiple sites.
This appendix describes the normal cell cycle. It provides an overview of the components that oversee cell cycle progression. It also explains how control of cell cycle is related to cancer.
Cell division is part of a normal cell cycle. When the cells divide uncontrollably, an abnormal growth occurs that may result into a tumor. Tumor may be:
Benign: Diseased cells do not invade neighboring tissues or pass on to other parts of the body.
Malignant: Diseased cells invade other tissues and are capable of spreading to distant parts of the body.
A quick review of normal cell cycle shall facilitate a better understanding of the...
