🧬 Tumour Immunology & Antigens – Ultimate Flashcards (16)

1. What are the "Emerging Hallmarks" of cancer related to immunology?

Evading Immune Destruction: Cancer cells find ways to evade or suppress the immune system.

Reprogramming Energy Metabolism: Cancer cells change how they use energy to support rapid growth².

what is the difference between a "Hot" and "Cold" tumour?

Hot Tumours: Contain many infiltrating immune cells; patients generally have better survival rates as they respond more effectively to immunotherapy.

Cold Tumours: Lack significant immune cell infiltration and are harder to treat.

What is meant by the phrase "Tumours are wounds that do not heal"?

Postulated by Dvorak (1986), this suggests that tumours exploit the body's normal wound-healing response (recruiting neutrophils and macrophages) to promote their own growth⁵.

What is the primary evidence for an immune response to tumours?

• Lymphocyte Infiltrates: The presence of immune cells in the tumour often correlates with a better prognosis.

• Immunosuppression Risk: A higher incidence of tumours in immunosuppressed individuals. 7

• Spontaneous Regression: Rare cases where tumours disappear without treatment.

What is the difference between TSA and TAA?

• Tumour Specific Antigens (TSA): Unique to cancer cells and not found on normal cells (e.g., mutated p53)

• Tumour Associated Antigens (TAA): Also found on normal cells but are expressed at much higher levels in cancer (e.g., Tyrosinase in melanoma)

How do tumour cells "escape" the immune system?

• Down-regulating MHC Class I: If they stop expressing MHC I, they become "invisible" to CD8+ T-cells

• Antigen Shedding: Releasing antigens into the blood to distract the immune system.

• Production of Inhibitory Factors: Creating a suppressive microenvironment

What are "Oncofetal Antigens"?

Proteins normally expressed only during fetal development that are "re-expressed" by cancer cells (e.g., CEA in colorectal cancer and Alpha-fetoprotein in liver cancer)

What are "Viral Antigens" in cancer?

Antigens produced by oncogenic viruses that trigger an immune response. Examples include HPV (Cervical cancer), EBV (Burkitt’s lymphoma), and HBV (Hepatocellular carcinoma)

What is the role of Mutated Oncogenes like ras and p53?

Mutations in these genes can create new, "non-self" epitopes that can be processed and presented to induce cellular and humoral immune responses

What is "Aberrant Expression" of normal proteins?

When a normal protein like Tyrosinase is produced in quantities high enough to be recognized by T-cells, despite being a "self" protein

How are Mucins used as diagnostic tools?

Abnormal forms of surface carbohydrates/mucins like CA-125 (Ovarian) and MUC-1 (Breast) are used as biochemical tumour markers in the lab

What are the challenges in creating Cancer Vaccines?

Choosing the right antigen and adjuvant, generating long-term memory, and overcoming the aging immune system or tumour-induced immunosuppression.

What are "Undefined Antigens" in vaccines?

Using whole irradiated cell lines or tumour lysates as a vaccine to present a broad range of known and unknown antigens to the immune system

What is the "Immunosurveillance" theory?

The idea that the immune system constantly "scans" the body to identify and destroy transformed (cancerous) cells before they form a detectable tumour

1. What is the goal of Cancer Immunotherapy?

To stimulate or "educate" the patient's own immune system to recognise and eliminate cancer cells, either alone or alongside surgery and chemotherapy