Neoplasia

Question 1

What is neoplasia?

Answer 1

Disease of multicellular organisms resulting in uncontrolled cell growth which continues in the absence of a stimulus. Neoplastic cells invade the tissue and kill the host.

Question 2

Describe some features of benign tumours

Answer 2

Well circumsised
Resemble the tissue of origin
Slow growing

Question 3

What are the 2 types of carincomas?

Answer 3

Carcinoma = epithelial malignancy

Invasive - neoplastic cells invade throug the epithelium to the basement membrane
Non invasive - neoplastic cells are confined to the basement membrane

Question 4

What is dysplasia?

Answer 4

Normall cellular changes ( changes in size/shape/appearance/no)
Predispose to neoplasia in the future if all dysplastic cells invade the entire epithelium

Dysplastic cells gain mutations -> neoplastic cells/carcinoma may be invasive or non invasive

Question 5

Compare features of benign vs malignant tumours

Answer 5

Benign:

• Slow expansive growth
• Do not metastasise
• Normal nuclear: cytoplasmic ratio
• Normal chromatin
• Low mitotic count
• Encapsulated
• Uniform cell shape and size

Malignant

• Fast rapid growth
• Metastasise
• Non encapsulated
• Pleomorphic cells
• Higher mitotic count
• Hyperchromatic + dark stain DNA
• Increased nuclear: cytoplasmic ratio

Question 6

What are some examples of malignant transformation?

Answer 6

• Avoid apoptosis and immune destruction
• Non responsive to growth signals
• Angiogenesis
• Uncontrolled cell division
• Metastases
• Imortal ( limitless replication)

Question 7

What is angiogenesis?

Answer 7

The growth of new blood vessels from the host vasculature

Question 8

How does angiogenesis result in metastatic spread?

Answer 8

Small tumours without their own blood supply are limited in their growth.

Pro angiogenic factors act on the host vasculature
Tumour forms own blood supply
Tumours recieves own nutrients and oxygens allowing it to expand and grow and spread further

Question 9

What is metastasis?

Answer 9

The spread of a tumour from its site of origin to a distant site

Question 10

Describe the metastatic cascade

Answer 10

Angiogenesis
Tumour cells down regulate adhesion molecules e.g MMP genes

Tumour cells break of from the primary tumour

Tumour cells penetrate blood vessels + lymphatics in INTRAVASATION

Tumour cells survive in the blood as CTC

Tumour cells escape blood vessels/lymphatics in extravasation

Colonisation + angiogenesis at a new site. Tumour cells arrest in a capillary bed and invade through the epithelium

Question 11

What are some examples of tumour spread?

Answer 11

Blood vessels
Lymphatics: Permeation + embolisation
Direct extension
Movement within body cavities