Microsatellite Instability (MSI)

Add Clarity to DNA Mismatch Repair Markers

February-archives

Colon cancer stained with MLH-1 Antibody

MLH-1

• Aids in identifying gene most likely responsible for MSI

• MLH1 expression may correlate with survival

• Loss of function is almost always coupled with concurrent loss of PMS2

Buy MLH-1
Colon cancer stained with MSH2 antibody

MSH2

• MSH2 binds to a mismatched DNA duplex

• Joined by a heterodimer of MLH1 and PMSH

• Loss of function manifests as absent IHC expression of MSH2 & MSH6

Buy MSH2
Colon cancer stained with MSH6 antibody

MSH6

• MSH6 is a heterodimer of MSH2

• Predicts more MSH gene mutation than molecular method

• Isolated absence of protein suggests mutation in the MSH6 gene

Buy MSH6
Colon cancer stained with PMS2 antibody

PMS2

• PMS2 forms a heterodimer with MLH1

• Isolated absence of protein indicates mutation in the PMS2 gene

• Endometrial carcinoma linked to defects in MLH1/PMS2 genes

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References:
1. Bellizzi, AM & Frankel WL. Adv Anat Pathol 2009;16:405 2. Shia, J. J Mol Diagn 2008;10:293 3. Backes, FJ, et al. Gynecologic Oncol 2009;114:486