Synopsis
Explain how acquired and inherited genomic alterations drive malignant behaviour, distinguish driver from passenger findings, and interpret tumour and germline results without overstating certainty.
- Cancer develops through accumulated alterations that confer selective growth, survival, invasion or immune-evasion advantages; no single universal mutation explains every tumour.
- Oncogenes usually act through gain of function, so one activated allele can promote signalling; examples include RAS pathway activation and ERBB2 amplification.
- Tumour-suppressor genes restrain proliferation, repair DNA or trigger cell death; loss of both functional copies commonly removes that restraint, although mechanisms vary.
Investigation priorities
Establish lineage and direct focused molecular testing.
Management branches
A cancer diagnosis may need classification, inherited-risk assessment or a treatment biomarker.
- Confirm histological diagnosis, tumour site, stage, available material and the precise decision that a molecular result would change.
- Choose an assay whose validated scope covers the required variant types, and record whether testing is somatic, germline or paired.