Final answer:
Cancer is caused by uncontrolled cell growth due to mutations that disrupt the cell cycle, usually resulting from carcinogen exposure. Tumors, which are masses of abnormal cells, can harm surrounding tissues if malignant. Cancerous cells divide rapidly, leading to increased mutations and the potential spread through processes like angiogenesis.
Step-by-step explanation:
What Causes Cancer?
Cancer is a disease characterized by uncontrolled cell growth due to mutations in a cell's DNA, affecting genes that regulate the cell cycle. These mutations can be the result of exposure to carcinogens such as pathogens, chemicals, or radiation. Cancerous cells divide much faster than normal cells, leading to the formation of a mass of abnormal cells known as a tumor. If a tumor invades and disrupts surrounding tissues, it is considered cancerous and can be malignant, potentially leading to death.
Role of Tumors in Cancer
A tumor is a mass of abnormal tissue formed when these mutated cells multiply without the usual checks and balances. Tumors can be benign if they do not harm neighboring tissue, or malignant if they invade surrounding tissues and organs. The aggressive multiplication of cancerous cells means they consume more nutrients and space, depriving normal cells and causing damage. The process of turning a normal cell into a cancerous one involves the failure of tumor-suppressor genes, which normally inhibit cell growth.
Impact of Cancerous Cell Division and Spread
The rapid division of cancerous cells increases the mutation rate, which may lead to further aggression and resistance to treatment. Cancer can spread through processes like angiogenesis, which is the formation of new blood vessels that provide tumors with the necessary nutrients and oxygen for further growth. Treatments focus on targeting these fast-dividing cells and may include surgery, chemotherapy, radiation therapy, and targeted therapies aimed at specific cancer characteristics.