Cancer

Definition

Cancer is a group of diseases characterized by uncontrolled cell growth and division, leading to the formation of tumors that can invade surrounding tissues and spread to other parts of the body. It arises from genetic mutations that disrupt normal cellular processes, particularly those regulating cell division and death, making it a complex interplay between genetic and environmental factors.

5 Must Know Facts For Your Next Test

1. Cancer can arise due to various factors including genetic predisposition, environmental exposures, and lifestyle choices such as diet and smoking.
2. In cancer cells, apoptosis is often disrupted, allowing damaged cells to survive and proliferate instead of undergoing programmed cell death.
3. There are several types of cancer, including carcinomas (from epithelial cells), sarcomas (from connective tissues), leukemias (blood cancers), and lymphomas (cancers of the lymphatic system).
4. Epigenetic alterations, such as DNA methylation and histone modification, can affect gene expression without changing the underlying DNA sequence, playing a significant role in cancer progression.
5. Cancer treatment can include surgery, radiation therapy, chemotherapy, and targeted therapies that focus on specific molecular targets involved in tumor growth.

Review Questions

• How does apoptosis relate to cancer development and progression?
  • Apoptosis is a natural process where cells undergo programmed death to maintain healthy tissue. In cancer, this process is often disrupted, allowing abnormal cells to evade death and continue dividing uncontrollably. This failure to undergo apoptosis contributes significantly to tumor growth and survival, making it a critical factor in understanding how cancers develop and progress.
• Discuss the role of epigenetic alterations in the initiation and progression of cancer.
  • Epigenetic alterations refer to changes in gene expression that do not involve changes to the DNA sequence itself. These modifications can silence tumor suppressor genes or activate oncogenes, driving cancer initiation and progression. Understanding these alterations helps researchers identify potential therapeutic targets and develop strategies to reverse the effects of these changes in cancer cells.
• Evaluate how both genetic mutations and environmental factors contribute to the complex nature of cancer.
  • Cancer's complexity stems from a combination of genetic mutations and environmental influences. Genetic mutations may occur due to inherited predispositions or as a result of exposure to carcinogens like tobacco smoke or radiation. Environmental factors can trigger epigenetic changes that further promote tumor development. This interplay highlights the need for comprehensive approaches in cancer prevention, diagnosis, and treatment that consider both genetic susceptibility and lifestyle factors.

Related terms

tumor: An abnormal mass of tissue that forms when cells divide uncontrollably. Tumors can be benign (non-cancerous) or malignant (cancerous).

apoptosis: A form of programmed cell death that plays a critical role in maintaining tissue homeostasis by eliminating damaged or unnecessary cells.

carcinogen: Any substance or exposure that can lead to cancer development by causing genetic mutations or promoting tumor growth.