Targeted Therapy and the Resistance That Follows It
A drug aimed at a driver works for as long as the driver is required and the target is unchanged. This stop works through the routes back: mutation of the target, bypass signalling, and selection of a clone that was already present.
What a learner can do afterwards
- Explain oncogene dependence and where the therapeutic window comes from
- Classify a stated resistance mechanism as on-target or bypass, and say what evidence separates them
- Argue from clonal structure why resistance can appear faster than mutation rates alone suggest
1 · Read
You start from strong dependence. Some tumours lean hard on one hyperactive driver pathway while healthy cells spread signaling across many inputs. Blocking that crutch can harm the cancer more than normal tissue, but benefit is conditional and healthy tissue can still suffer.
You sort relapse into two routes. On target resistance changes the drug binding pocket so the inhibitor no longer grips, while the pathway stays essential. Bypass resistance leaves the target blocked but switches growth to a parallel route the drug never aimed at.
You sequence a relapsed tumour. Fresh mutations in the drug target would point toward testing a next generation inhibitor. A newly active parallel receptor with the original target still suppressed argues bypass, which would point toward testing a second blockade; both are hypotheses to test, not orders.
You expect resistance that can outrun fresh mutation. A large tumour may already harbor rare variants, or new ones can arise during treatment, so selection has raw material either way.
You read the therapeutic window as a dose gap. It spans the dose that stalls the tumour to the dose that harms the patient, and strong dependence can widen it; the gap never promises safety.
You plan lasting control with combinations. You try to close escape routes early, guided by repeat sequencing of the relapsed tumour.
You explain the window by strong dependence, you classify relapse as on target or bypass from fresh sequencing, and you plan for clones that may pre exist or arise.
Original readings written in-repo; academy video links retained with unknown terms.
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
This opens up
Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.