Year 1: Behaviour of Tumours

Question 1

What is carcinogenesis?

Answer 1

• a multi-step process that usually requires several mutations to initiate cancer

Question 2

What can a stem cell become to become a cancer stem cell?

Answer 2

• normal progenitor cell -> mutated progenitor cell -> cancer stem cell
• normal stem cell -> mutated stem cell -> cancer stem cell
• normal differentiated cell -> mutated differentiated cell -> cancer stem cell
• cancer stem cells then form a tumour mass

Question 3

Why do patients die from cancer?

Answer 3

• spreads to multiple organ sites
• metastatic disease in vital sites
• intracranial tumours/big burden
• immunosuppression
• organ failure
• haemorrhage
• late second malignancies

Question 4

What does tumour growth rate depend on?

Answer 4

• doubling time of tumour cells (lengthens as tumour grows)
• fraction of tumour cells in replicative pool (tumour stem cells)
• rate at which tumour is shed or lost (apoptosis, maturation)
• extent of differentiation of tumour

Question 5

How are cancer cells not under normal growth controls?

Answer 5

• immortal
• high cell division
• centre of tumour does not receive sufficient food and oxygen
• ischemic necrosis
• shedding/loss of tumour cells
• dead cells = apoptotic figures

Question 6

What are the different stages of differentiation of a tumour?

Answer 6

• well differentiation (mature cells)
• poorly/undifferentiated (primitive cells, aggressive growth, rate of growth of malignancy proportionate to differentiation)
• benign tumour well differentiated

Question 7

What are the steps of metastasis?

Answer 7

• vascularisation of tumour
• cells detach from primary tumour
• basement membrane degraded and invade into ECM
• intravasation on nearby blood vessels
• tumour cells circulate in vascular system
• some cells adhere to walls of blood vessels
• extravasation and migration to local tissue
• secondary tumour can form

Question 8

What is the significance of nodal metastasis?

Answer 8

• prognosis = important component of TNM staging system
• therapeutic = adjuvant therapy required, extent of nodal involvement, risk of recurrence
• sentinel node biopsy = radioactive tracer and dye to establish cancer presence
• radial mastectomy to remove breast lymph nodes

Question 9

What does tumour staging involve?

Answer 9

• size of tumour
• extent of growth/spread
• number system or TNM

Question 10

What is the TNM method of staging?

Answer 10

• T - size of cancer and how far it has spread into local tissue
• N - has it spread to lymph nodes and to what extent, 0-3, 3 greatest
• M - has it metastasised, 0 or 1

Question 11

What are paraneoplastic syndromes?

Answer 11

• not caused by direct invasion or metastasis of tumour
• accompany malignant disease
• vary in impact and presentation
• arise from tumour secretion of hormones, peptides, cytokines
• can be endocrine, neurologic, dermatologic and rheumatologic or haematologic

Question 12

What are some examples of paraneoplastic syndromes?

Answer 12

• hormone: ACTH -> cushing
• peptides: C peptide -> hypoglycaemia
• cytokines: IL-6 -> thrombocytosis
• antibody from B cell: anti AChR -> myasthenia gravis