Gastrointestinal Cancers Flashcards
What is a primary tumour?
Arising directly from a cell in an organ
What is a secondary organ?
Spread from another organ, directly, or by other means
What are 6 hallmarks of cancer?
Sustaining proliferative signalling Evading growth suppressors Activating invasion and metastasis Enabling replicative immortality Inducing angiogenesis Resisting cell death
What is sustaining proliferative signalling
Ability to sustain chronic proliferation, fundamental trait of cancer cells. Cancer cells reregulate release of growth-promoting signals, enabling signals are conveyed by growth factors that bind cell-surface receptors (intracellular tyrosine kinase domains). The latter proceed to emit signals via branched intracellular signalling pathways that regulate progression through the cell cycle as well as cell growth
How do cancer cells sustain proliferative signalling?
- Self-synthesis of growth factor ligands, respond to via the expression of cognate receptors, resulting in autocrine proliferative stimulation.
- Alternatively, cancer cells may transmit signals to stimulate normal cells within the supporting tumour-associated stroma, which reciprocate by supplying cancer cells with growth factors.
- Receptor signalling deregulated by elevating levels of receptor proteins displayed at cancer cell surface; hyperresponsive to growth factor ligand. Structural alterations in the receptor molecules that facilitate ligand-independent firing.
How do cancer cells evade growth suppresors?
Defects in RB pathway permits cell proliferation. RB transduces growth-inhibitory signals, TP53 inputs from stress and abnormality sensors; degree of damage to genome is excessive, TP53 can halt cell-cycle progression. Sensation of irreparable damage can trigger apoptosis.
Which is a common tumour suppressor gene?
tp53
What are tumour suppressor genes?
Limit cell growth and proliferation.
Which proteases are involved in apoptosis?
Capsases
How do tumour cell circumvent apoptosis?
Loss of tp53 tumour suppressor gene
Which enzyme is responsible for adding telomere repeat segments to the end of telomeric DNA?
Telomerase
Which cancer is associated with squamous epithelial cells?
Squamous cell carcinoma (SCC)
Which cancer is associated with glandular epithelium?
Adenocarcinoma
Which cancer is associated with enteroendocrine cells?
Neuroendocrine tumours (NETs)
Which cancer is associated with intestinal cells of Cajal?
Gastrointestinal stromal tumours (GISTs)
Which cancer is associated with smooth muscle?
Leiomyoma/meiomyosarcoma
Which cancer is associated with adipose tissue?
Liposarcoma
Which organs are typically concerned in GI tumours?
Oesophagus Liver Pancreas Colon Gastric cancer stomach
Which cancer is the most common, in terms of incidence within the UK?
Breast cancer, followed by prostate and lung cancer
What is the fourth most prevalent diagnosed cancer in the UK?
Bowel cancer
Which cancers have the highest mortality?
Liver Pancreatic Oesophageal Stomach Gallbladder
Which criteria is employed for testing asymptomatic individuals for cancer?
Wilson & Jugner Criteria
Which cancer has the lowest survival rate?
Pacreatic cancer
Which surgical intervention helps to improve 5-year survival diagnoses?
Resectable intervention for cancer
Why is colorectal associated with a higher 5-year survival rate?
• The large bowel (colorectal) is mobile with a mesentery, these structures are thus isolated from other peritoneal organs, thus metastasises to other organs is less likely when compared peritoneal organs of the small bowel.
What are the 6 Wilson & Jugner criteria for cancer screening tools?
- The condition sought should be an important health problem
- There should be an accepted treatment for patients with recognised disease
- Facilities for diagnosis and treatment should be available
- There should be a recognisable latent or early symptomatic stage
- There should be a suitable test or examination
- The natural history of the condition, including development from latent to declared disease, should be adequately understood.
What is the screening tool for colorectal cancer?
- Faecal Immunochemical Test (FIT) - Detects haemoglobin in faeces, every 2 years for everyone aged 60-74.
- One-off sigmoidoscopy – Individuals aged >55 to remove polyps (reduces future risk of cancer).
What is the screening tool for oesophageal cancer?
Regular endoscopy