Week 5 - Leukemias, Lymphoma & Cancer Immunity

Question 1

What is Cancer?

Answer 1

Arises from uncontrolled proliferation and spread of transformed cells

Question 2

What are the 6 genetic traits of Cancer

Answer 2

• Self-sufficiency
• Insensitivity to anti-growth signals
• Evading apoptosis
• Limitless replicative potential
• Sustained angiogenesis
• Tissue evasion and metasteses

Question 3

What causes series of acquired genetic mutations

Answer 3

• random somatic mutations
• environmental factors
• errors in DNA recomb
• inherited alleles

Question 4

Trait 1 - Self Sufficiency -> Explain how this happens

Answer 4

• Proto-oncogenes (normal genes) get converted into oncogenes via mutation
• Oncogenes generally cause self sufficiency from growth signals

Question 5

What is the c-myc oncogene?

Answer 5

= transcription factor normally associated with turning on genes associated with cell division
- when expression of it is altered, it can result in unrestricted growth of the cell

Question 6

Trait 2 - Insensitivity to Antigrowth Signals -> Explain how this occurs

Answer 6

• within normal cells, multiple anti-proliferative signals operate to maintain homeostasis -> mutations lead to not working properly -> e.g p53 gene is affected

Question 7

Trait 3 - Evading Apoptosis -> explain how this occurs

Answer 7

Apoptosis is a major way to remove cells with an oncogenic mutation however cancerous cells can acquire resistance to this apoptosis

Mutations in any of the genes in the diagram can lead to evading apoptosis

Question 8

Trait 4 - Acquisition of Limitless Proliferative Capacity -> explain how ti occurs

Answer 8

Senescence = cells reach a limit to the number of times they divide
- mechanism of senescence is chromosomal instability caused by erosion of telomeres -> can be overcome by dysregulation of enzyme telomerase

Question 9

What is Leukemia?

Answer 9

= a malignant proliferation of bone marrow-derived cells whose mature forms are normally found in blood or bone marrow

Question 10

What are some complications of Leukemia?

Answer 10

• bone marrow failure
• anaemia
• bleeding
• infection

Question 11

What are Lymphomas?

Answer 11

= tumours of non-circulating lymphoid cells generally in the lymph nodes

Question 12

What are Myelomas?

Answer 12

= Malignancy of plasma cells forming lesions in the bone marrow

Question 13

Are Malignancies more common in B cells or T cells?

Answer 13

B cells bc are constantly playing/mutating their genomes so more likely to mess up

Question 14

What are symptoms of Acute Lymphoblastic Leukemia? is it curable?

Answer 14

fever, lethargy, bleeding, anorexia, hepatosplenomegaly, lymphadenopathy

curable

Question 15

Acute Lymphoblastic Leukemia cells

Answer 15

Question 16

Chronic Lymphocytic Leukemia cells

Answer 16

Question 17

What are symptoms of Chronic Lymphocytic Leukemia? is it curable?

Answer 17

fever, lethargy, bleeding, anorexia, hepatosplenomegaly, lymphadenopathy

not curable but treatable

Question 18

Does the immune system react against tumours?

Answer 18

yes

Question 18

What are treatments for immune cell tumours?

Answer 18

• surgery
• chemotherapy
• prophylactic antibiotics
• bone marrow transplants

Question 19

How does immune system respond to tumours?

Answer 19

• Dendritic cells endocytose tumour antigen -> migrate into draining lymph nodes -> initiate T cell
• Activated CTLs migrate back to tumour site to kill tumour cells

Question 20

Tumour Antigens summary

Answer 20

Question 21

How do tumours evade immune system?

Answer 21

• Antigen loss
• Class 1 MHC deficient tumour cell
• Prod. of immunosuppressive proteins or expression of inhibitory cell surface proteins