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Difference between revisions of "Talk:Lynch syndrome"
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COLON, RESECTION: | COLON, RESECTION: | ||
- ADENOCARCINOMA. | - ADENOCARCINOMA. | ||
- TUMOUR HAS BEEN EXAMINED FOR THE MISMATCH REPAIR GENE PRODUCTS. | |||
MLH1: ABNORMAL, FOCAL MINIMAL STAINING IN THE TUMOUR COMPARED TO BENIGN BACKGROUND CELLS. | |||
MSH2: NORMAL NUCLEAR STAINING. | |||
MSH6: NORMAL NUCLEAR STAINING. | |||
PMS2: ABNORMAL, ABSENT NUCLEAR STAINING, SEE COMMENT. | |||
COMMENT: | |||
Abnormal immunohistochemical staining is highly correlated (>99%) with tumours that | |||
show high-frequency microsatellite instability (MSI-H) and this tumour should be | |||
consider to have microsatellite instability (MSI-H). | |||
The MLH1 staining is abnormal; it is very week and focal in the lesion, when compared | |||
to the background tissues. PMS2 is completely absent. | |||
The expression of PMS2 is lost in tumours with abnormal MLH1 expression. As the MLH1 | |||
is decreased but not completely absent, this individual's PMS2 status cannot be determined | |||
by immunohistochemistry, and the individual could be considered for furthe investigation | |||
of MLH1 status. | |||
Abnormal MLH1 expression can be seen in sporadic tumours (associated with MLH1 | |||
hypermethylation) as well as in association with Lynch syndrome (LS), also known as | |||
hereditary non-polyposis colon cancer (HNPCC). Features associated with LS include young | |||
age of onset, strong family history of cancer (especially endometrial, urothelial, other | |||
gastrointestinal), and multiple primary LS cancers in one individual. If this patient | |||
has these characteristics suggestive of LS, a referral to a genetic counsellor | |||
is suggested. | |||
</pre> | </pre> | ||