OnCo
ideasIdea

Attack the backup copy when a tumour has lost the original gene

Tumours often lose one of a pair of near-identical genes. They then depend entirely on the remaining copy, which a drug can block, killing only the cancer.

SMARCA4-mutant cancers depend on SMARCA2; MTAP-deleted cancers depend on PRMT5 in a methylthioadenosine-dependent manner; other paralog pairs (for example ARID1A/ARID1B, ENO1/ENO2) show the same logic. Paralog dependencies are the most systematic way to exploit tumour-suppressor loss, which is otherwise undruggable. Selective SMARCA2 degraders and MTA-cooperative PRMT5 inhibitors have reached the clinic.

Hypothesis
A genome-wide paralog dependency map across 500 cell lines yields at least ten new pairs where loss-of-function in the tumour creates a greater than five-fold selective dependency confirmed in vivo.
Rationale
Tumour suppressor loss is more common than oncogene activation but has almost no direct therapies; paralog buffering converts loss into a positive drug target, exactly as PARP inhibition did for BRCA loss.
What would test it
Dual-guide CRISPR paralog screens in a large line panel with matched genotype annotation; validate the top hits in isogenic pairs and PDX models before chemistry investment.
Maturity
early clinical
Who has to act
research
Cost to try
Medium ($1M to $50M)
Years to first evidence
5
Bottlenecks it attacks
  • The undruggable drivers · The proteins that drive most cancers, such as MYC, mutant p53 and most RAS variants, still have no good drug.

Connected

8top

Pages like this

not linked directly; found by shared links