Stratified medicine Lecture 2

Question 1

Define stratified medicine

Answer 1

The process for selecting patients for specific therapies using a biomarker

Biomarker = a measured indicator of a disease process

Question 2

What are the features of a good biomarker

Answer 2

1. Sensitive - i.e. high true positive rate (if they have cancer the test says they have)
2. Specific - i.e. low false positive rate (if they haven’t got the cancer the test doesn’t say they have)
3. Reproducible
4. Only good for the disease being examined
5. Cheap

You can measure how good a biomarker is by looking at its sensitivity and specificity

Question 3

What types of biomarker are there

Answer 3

• Complex i.e. multi-gene
• Simple - single mutation i.e. KRAS
• Predictive - predict response to therapy
• Prognostic - predicts how patient will survive or how disease will progress

Question 4

Describe predictive biomarker used in oesophageal cancer

Answer 4

• OR3A4 methylation status is an accurate tissue marker of neoplastic progression of non-dysplastic Barret’s oesophagus
• Thus it is a good predictive biomarker
• Helps determine who needs endoscopic screening