Table of Contents
Postmeiotic segregation increased 2 (PMS2) is part of the DNA mismatch repair (MMR) pathway, which is utilized by normal proliferating cells to repair mutations that may occur during DNA replication. PMS2 deficiency or loss of function results in an increased mutation rate and contributes to the development of sporadic colorectal carcinoma as well as hereditary non-polyposis colorectal carcinoma (HNPCC, also called Lynch syndrome). HNPCC accounts for 1-5% of colorectal cancers (1, 2). Antibodies to PMS2 are useful for identifying mismatch repair deficiencies in tumors of the gastrointestinal tract, including HNPCC and associated extracolonic cancers. PMS2 deficiency has also been reported in endometrial, ovarian, breast, esophageal, and ampullary carcinomas, and melanomas. PMS2 is dependent upon MLH1 for stable expression, thus at the protein level, both sporadic and hereditary colorectal cancers deficient in MLH1 generally exhibit concomitant loss of PMS2.
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type or one (1) unbaked, unstained slide cut at 4-5 microns for H&E staining (required) and two to three (2-3) positively charged unstained slides cut at 3-4 microns for each test/antibody ordered.
Storage and Transport
Use cold pack during transport of paraffin blocks and unstained slides. Cold pack should not be placed in direct contact with the specimen during shipping.
Specimen Rejection Criteria
All specimens must be submitted according to the test directory instructions. Before submitting specimen, please carefully review specimen requirements.
Listed below are possible causes for delays in specimen processing or possible specimen rejections or cancellations:
- No patient identification on requisition form
- No patient identification on specimen container or slides
- No referring provider
- No account information provided
- No test ordered on requisition
- No specimen source provided
- Inappropriate specimen type
- Insufficient volume for analysis
- Inappropriate specimen container
- Improper specimen transport
- Specimen leaked in transport
- Specimen submitted in incorrect or expired transport media
- Slides broken beyond repair on receipt
- Conflict between patient name on specimen and requisition form
- Specimen not properly preserved
- Sample containing a needle
A representative from Client Services will attempt to contact your office to resolve specimen problems. Additional documentation may be requested from your office to be returned by fax. In the event that resolution is not possible, the specimen may be returned to your office.
Turn Around Time (TAT)
88341, 88342, 88360