Here's a breakdown of why:
* Normal Cell Division: In a healthy organism, cell division is tightly regulated. Cells only divide when needed for growth, repair, or replacement. There are checkpoints in the cell cycle to ensure accuracy and prevent errors.
* Cancerous Cell Division: In cancer, this regulation breaks down. Cells begin dividing uncontrollably, ignoring the normal signals to stop. This leads to:
* Tumor Formation: The accumulating cells form a mass called a tumor.
* Invasion and Metastasis: Cancer cells can invade nearby tissues and spread to distant parts of the body (metastasis).
Key factors contributing to uncontrolled cell division:
* Mutations in Genes: Changes in genes that control cell growth and division can lead to cancer. These mutations can be inherited or acquired through environmental exposures.
* Immune System Dysfunction: The immune system normally eliminates abnormal cells, but it can become weakened or unable to recognize cancerous cells.
Consequences of Uncontrolled Cell Division:
* Tissue Damage: The uncontrolled growth of cancerous cells can damage surrounding tissues and organs.
* Functional Loss: Cancer cells can disrupt the normal function of organs and systems.
* Death: In advanced stages, cancer can be life-threatening.
Important Note: It's crucial to understand that not all tumors are cancerous. Benign tumors grow slowly and don't spread, while malignant tumors are cancerous and can invade and metastasize.
