Schematic diagram of the pathophysiology colorectal cancer?
Colorectal cancer (CRC) is a complex disease involving multiple genetic and environmental factors. Here's a schematic diagram depicting the key steps in the pathophysiology of CRC:
1. Genetic Predisposition:
- Inherited genetic mutations, such as Lynch syndrome (hereditary nonpolyposis colorectal cancer) or familial adenomatous polyposis (FAP), increase the risk of developing CRC.
- Somatic mutations can occur in various genes, including APC, KRAS, TP53, and PIK3CA, during the development of sporadic CRC.
2. Aberrant Cell Growth:
- Dysplastic changes: Normal colonic epithelial cells acquire genetic alterations, leading to abnormal growth and the formation of dysplastic crypts.
3. Adenoma Formation:
- Adenomas are non-cancerous polyps that develop from dysplastic crypts. They can remain benign or progress to cancer over time.
4. Adenocarcinoma Development:
- Over time, adenomas can accumulate additional genetic mutations, resulting in the development of adenocarcinoma, the most common type of CRC.
5. Invasion and Metastasis:
- Invasion: Cancer cells invade the deeper layers of the colon or rectum, penetrating the muscularis propria.
- Metastasis: Cancer cells spread to other parts of the body through the lymphatic system or bloodstream. Common sites of metastasis include the liver, lungs, and peritoneum.
6. Angiogenesis:
- To support their growth, cancer cells stimulate the formation of new blood vessels through a process called angiogenesis. This provides the tumor with essential nutrients and oxygen.
7. Immune Response:
- The immune system can recognize and attack cancer cells. However, CRC cells may evade immune surveillance by various mechanisms, such as expressing immune checkpoint proteins.
8. Environmental Factors:
- Certain lifestyle factors, like a diet high in red and processed meats, low fiber intake, obesity, smoking, and excessive alcohol consumption, can increase the risk of developing CRC.
9. Dysregulated Cell Signaling:
- Mutations in various genes can lead to dysregulated cell signaling pathways, such as the Wnt pathway, MAPK pathway, and PI3K pathway, contributing to uncontrolled cell growth and survival.
10. Epigenetic Alterations:
- Epigenetic changes, such as DNA methylation and histone modifications, can affect gene expression and contribute to the development and progression of CRC.
Understanding the pathophysiology of CRC is crucial for developing effective prevention, screening, and treatment strategies to combat this complex disease.