MLH1 by IHC

Alphabetical Test listing

MLH1 by IHC-12376 - Technical only, 12379 - Technical & interpretation

  
MLH1 by IHC
  
12376 - Technical only, 12379 - Technical & interpretation
  
LAB12376
LAB12379
  
Microsatellite instability marker
  
  • All IHC stains will include a positive control tissue
  
  • Used in a panel to identify patients at high risk for having hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome
  • IHC analysis is helpful for identifying the gene(s) responsible for the defective DNA mismatch repair within the tumor; the majority of MSI-H tumors show a loss of expression of at least 1 of the 4 mismatch repair genes
  • MSI-H phenotype or loss of protein expression by IHC within a tumor does not distinguish between somatic and germline mutations. Genetic testing of the gene indicated by IHC analysis can help to distinguish between these 2 possibilities
  
Tissue
  

Submit a formalin-fixed, paraffin-embedded (FFPE) tissue block

  

FFPE tissue block

  

FFPE tissue section mounted on a charged, unstained slide

  

Ambient (preferred)

  
  • Unlabeled/mislabeled block
  • Insufficient tissue
  • Slides broken beyond repair
  
AHL - Immunohistochemistry
  
Mo - Fr
  
1 - 2 days
  

Immunohistochemical staining and microscopic examination

  

If requested, an interpretive report will be provided

  

Specifications

  • Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an autosomal dominant hereditary cancer syndrome associated with germline mutations in the mismatch repair genes: MLH1, MSH2, MSH6, and PMS2
  • Patients with HNPCC have an increased risk of developing colorectal and endometrial cancer


Staining pattern

  • Nuclear staining of internal control lymphocytes, and MLH1 intact tumor cells
  • Absence of staining for MLH1 in tumor nuclei indicates loss of protein expression for this marker

References

  1. Burgart LJ: Testing for defective DNA mismatch repair in colorectal carcinoma. A practical guide. Arch Pathol Lab Med 2005;129:1385-1389.
  
88342 - 1st stain
88341 - each additional stain
  
10/30/2017
  
10/19/2018
  
01/12/2024