Cancer study guide (SP 25)

Module 1: Why Do Cells Become Cancerous?

What is Cancer?

• Definition: Cancer is a cellular disease characterized by uncontrolled cell division, which disrupts physiological functions.

• Causes: Genetic mutations, environmental factors, and lifestyle choices can all contribute to the development of cancer.

• Naming: Cancer is typically named after the organ or type of cell in which it originates.

• Odds of Getting Cancer: Statistics indicate varying risks depending on genetics, environment, and lifestyle, with some estimates suggesting a 1 in 3 chance for developing cancer in a lifetime.

How Does a Cell Normally Work?

• Cells are the smallest unit of life, fulfilling requirements such as energy production, metabolism, and reproduction.

• Specialization: Cells are specialized; for example, muscle cells differ from nerve cells in structure and function.

DNA and Gene Expression

• DNA: The molecule that carries genetic information essential for cell function and heredity.

• Gene Expression: Involves transcription (DNA to mRNA) and translation (mRNA to protein), determining how cells function and divide.

How Do Cells Divide?

• Cell Cycle: Includes phases (G1, S, G2, M) and checkpoints that regulate proper cell division.

• Checkpoints: Critical points in the cell cycle where the cell checks for DNA damage, proper size, and adequate nutrient availability, preventing unhealthy division.

Why Do Cells Stop Dividing Correctly?

• Mutations: Changes in DNA that can affect protein synthesis; they may be neutral, harmful, or beneficial.

• Tumor-suppressor Genes: Genes that regulate cell division and prevent cancerous growth.

• Proto-oncogenes: Normal genes that can become oncogenes due to mutations, leading to cancer development.

Module 2: How Does Cancer Affect My Body?

Characteristics of Cancer

• Uncontrolled cell division is a major characteristic.

• Mutations lead to discrepancies in DNA which can result in abnormal cell behavior.

• Tumors: An unspecialized mass of cells resulting from uncontrolled division.

• Angiogenesis: The process of new blood vessel formation to supply nutrients to tumors.

Metastasis

• Definition: The spread of cancer from its primary site to other parts of the body.

• Characteristics: Malignant tumors can metastasize through angiogenesis and by digesting surrounding tissues.

Stages of Cancer

• Staging: Cancer is classified from stage 0 (in situ) to stage 4 (advanced).

• Criteria: Factors include tumor size, lymph node involvement, and metastasis presence.

How Does Cancer Cause Death?

• Homeostasis Disruption: Cancer inhibits the body’s ability to maintain homeostasis, leading to systemic failures.

• Negative Feedback Mechanisms: These mechanisms are affected by cancer, enhancing the risk of life-threatening complications.

Module 3: How is Cancer Treated?

Cancer Diagnosis

• Genetic Testing: Individuals may be tested for genetic predisposition to cancer.

• PCR/DNA Sequencing: Techniques used to analyze genetic material for mutations.

• Microarrays: Used to detect the expression levels of multiple genes simultaneously.

• Blood Tests: Detect biomarkers that indicate the presence of cancer.

• Imaging Scans: Distinguish between screening (e.g., mammograms) and diagnostic (e.g., CT, PET, MRI) procedures.

• Biopsy: A procedure to extract tissue samples for examination.

Chemotherapy

• Mechanism: Targets the cell cycle to inhibit cell division, affecting all rapidly dividing cells.

• Side Effects: Common side effects arise due to damage to healthy cells, resulting in nausea, hair loss, etc.

Radiation Therapy

• Definition: The use of high-energy waves to damage DNA in targeted cancer cells.

• Types: External and internal radiation therapy; it can also be ineffective for metastatic cancer.

Future of Cancer Treatment

• Immunotherapy: Employs the immune system to fight cancer, including the use of vaccines to improve immune response.

• Gene Editing: Emerging techniques may allow precise corrections of mutations at the DNA level.