Referral of Colorectal Cases for Diagnostic Mismatch Repair IHC Testing
Mismatch repair (MMR) deficiency is seen in approximately 15% of colorectal cancers and can be a feature associated with sporadic colorectal cancer, or be caused by Lynch Syndrome.
The publication in 2014 of a revised dataset for reporting Colorectal Cancers by The Royal College of Pathologists (April 2014) and a National Institute for Health Research (NIHR) Health Technology Assessment (HTA) on strategies for testing for Lynch Syndrome (September 2014) requires the development of standardised IHC MMR testing in pre-specified groups of patients with colorectal cancer.
The Royal College of Pathologists dataset recommends MMR immunohistochemical (IHC) testing is considered a core item for patients under the age of 50 and in those adenocarcinomas, where assessment of prognosis is important, with morphological features of MMR deficiency.
More recently, NICE has published guidance which indicates that all new diagnoses of colorectal carcinoma, regardless of age, should be investigated either by IHC or MSI testing, with IHC being the preferred first-line method in the Manchester area.
The Immunohistochemistry Laboratory within the Adult Histopathology Department at Central Manchester University Hospitals NHS Foundation Trust has been performing MMR IHC testing for the consultants in Clinical Genetics for several years and it has been proposed that this laboratory will become the regional referral centre. The laboratory participates in the UK NEQAS ICC (HNPCC Module) accredited EQA scheme.
In order to ensure that the testing is performed correctly samples must conform to the criteria written out in the referral guidelines and a fully completed request form must accompany each sample. Please refer to the flow diagram to see how the samples will be handled once they arrive at Manchester Royal Infirmary. Please read the information provided on the following links for the material required for IHC testing and reporting and invoicing.
- Diagnostic MMR referral guidelines
- Diagnostic MMR referral request form
- Diagnostic MMR referral request flow diagram
Catherine Higgins, Advanced BMS IHC
0161 276 8786
Professor Ray McMahon, Consultant Histopathologist
0161 276 8815
Dr Lucy Foster, Consultant Histopathologist
0161 276 6954
(Last reviewed January 22nd 2018)