Inflammation and Carcinogenesis

Question 1

What are the hallmarks of cancer-related inflammation?

Answer 1

➢ Inflammatory cells and inflammatory mediators (e.g,
chemokines, cytokines and prostaglandins) present in
tumour tissues.
➢ Tissue remodelling is similar to that seen in chronic
inflammatory responses.
➢ Angiogenesis is similar to that seen in tissue repair
(required for the survival of cells within tumours of a
certain size & tumour metastasis).
➢ Inflammatory cells and mediators are present in the
microenvironment.

Question 2

How does inflammation lead to cancer?

Answer 2

1. When the cancer cells are struggling to gather nutrients and O2 they release cytokines which stimulate immune cells to infiltrate the tumour.
2. Release of these cytokines stimulates angiogenesis - providing nutrients and O2.
3. Incoming inflammatory cells also hit the developing tumour with free radicals that further damage cellular DNA.
   4.

Question 3

How can inflammation encourage metastasis?

Answer 3

Inflammation can also initiate tumour spread (metastasis) by stimulating enzyme production that help tumour cells eat through the molecules tethering them to their surroundings.

Question 4

What is the main infectious agent that causes cancer of the nasopharynx?

Answer 4

Epstein-Barr virus

Question 5

What is the main infectious agent that causes cancer of the bladder?

Answer 5

Schistosoma haematobium

Question 6

What is the normal gastric carcinogenesis pathway?

Answer 6

Normal gastric epithelium
Superficial gastritis
Atrophic gastritis
Intestinal metaplasia
Dysplasia
Gastric adenocarcinoma

Question 7

What does gastric intestinal neoplasia precede and what usually triggers it?

Answer 7

GIM considered to be a pre-neoplastic gastric lesion.

Usually triggered by chronic helicobacter pylori infection.

Question 8

What is the main virulence factor produced by H.pylori?

Answer 8

CagA (cytotoxin associated gene A)

Question 9

Bacterial epithelial interaction may be crucial in the development of cancer for what reasons?

Answer 9

1. Stimulation of epithelial (Toll-Like) receptors and consequent inhibition of apoptosis.
2. DNA-damaging (genotoxic) effects.