SUMMARY, EXPLANATION AND LIMITATIONS:
The repair of mismatch DNA is essential to maintaining the integrity of genetic information over time. Defects on the MMR (mismatched repair) system are involved in tumorous progression of sporadic human neoplasms, familial or hereditary in nature. In yeasts, proteins are denominated MutS homologous 2 (MSH2), MutL homologous (MLH) and PMS1, which is also homologous to MutL. MSH2 is considered to be involved in mismatched nucleotides initial recognition during MMR process. MSH2 binds to DNA altered duplex and later it binds to a complex formed by MSH1 and PMS1 heterodimer, the whole complex facilitates the DNA final reparation. Those mechanisms are also proposed for MMR in human. DNA mismatched reparation genes are involved in the development of a group of colorectal, gastric, and sporadic endometrial tumors. Microsatellites instability (MSI) or expression loss has been detected in 13-44% of gastric neoplasms, in 10-15% of colorectal neoplasms and in 17-23% of sporadic endometrial neoplasms. In these cases, MSI phenotype is consistent with a MMR gene somatic defect. MLH1 is transcriptionally inhibited in 90% of sporadic cancers, although in a minority of cases it shows a MLH1 or MSH2 inactivation due to a somatic mutation.
Staining pattern: Mainly nuclear, light cytoplasmic stain can be observed.
Positive control: Tissue sample from tonsil or colon.
This antibody is designed for the specific localization of human MSH-2 using IHC techniques in formalin-fixed, paraffin-embedded tissue sections.
Microsatellite instability or the absence of expression of proteins involved in DNA reparation (MLH-1 and MSH-2) are attributed a prognostic value in colorectal sporadic, gastric and endometrial neoplasms.