What a test can show
Germline sequencing and CNV analysis; tumour MMR proteins/MSI and MLH1 promoter methylation are often assessed first or in parallel.
Monogenic conditions
MLH1Lynch syndrome
Pathogenic germline variants impair mismatch repair and raise risks of colorectal, endometrial and several other cancers.
RELATIONSHIP VALIDITYHigh: established causality
ACTIONABILITYHigh after confirmation
SOURCE CHECKLinks and claim boundaries are editorially checked; external expert review is stated only with named disclosure
Practical meaning
A correct sequence of tumour and germline tests helps distinguish a sporadic tumour from an inherited syndrome.
Where knowledge ends
Tumour loss of MLH1/PMS2 is not synonymous with Lynch syndrome; sporadic MLH1 promoter hypermethylation is possible.
SOURCES AND VERSION
Verifiable, not ‘trust us’.
Updated: 14 August 2026. Any clinical interpretation requires the exact variant, testing method, family information and medical context.