Microsatellite Instability

ORDER CODE: TMSI

ORDERING

SPECIMEN

PROCESSING

RESULTS

Test Code

SHC TEST CODE LPCH TEST CODE
LABTMSI LAB3008

Synonyms

MSI

Clinical Utility

Microsatellite instability (MSI) is detected in 90% of colon cancers that are part of the Hereditary Non-Polyposis Colorectal Carcinoma  (HNPCC) syndrome, and in 15% of sporadic colorectal carcinomas. It is the consequence of germline mutation(s) in or somatic inactivation of mismatch repair genes, such as MLH1, MSH2, MSH6, or PMS2. Due to their repetitive sequence composition, microsatellite sequences are especially vulnerable. This assay is based on multiplex PCR amplification of 5 microsatellites: BAT-25, BAT-26, MONO-27, NR-21, and NR-24. If there is a difference in the length of a certain microsatellite in the patient’s normal and tumor samples, the microsatellite is considered unstable. If two microsatellite loci (of 5) are unstable, the tumor is designated microsatellite instability high (MSI-H). If only one locus is unstable, the tumor is considered microsatellite instability low (MSI-L), and if no loci are unstable, the tumor is designated microsatellite stable (MSS).

CPT Code

81301
Preferred Specimen(s)
FFPE tissue, tumor and normal
Container Type
FFPE block for tissue

Volume

REQUESTED VOLUME MINIMUM VOLUME(PEDIATRIC)
Varies Varies

Specimen Stability

Special Handling

Sample should be kept at refrigerator temperatures and arrive in lab within 48 hours of collection. Ship on ice.

Department

Molecular Pathology

Standard Run Time(s)

Weekly

Turnaround Time

ROUTINE STAT
7-14 days 7-14 days

Methodology

PCR / Fragment Analysis

Test Code

SHC TEST CODE LPCH TEST CODE
LABTMSI LAB3008

Synonyms

MSI

Clinical Utility

Microsatellite instability (MSI) is detected in 90% of colon cancers that are part of the Hereditary Non-Polyposis Colorectal Carcinoma  (HNPCC) syndrome, and in 15% of sporadic colorectal carcinomas. It is the consequence of germline mutation(s) in or somatic inactivation of mismatch repair genes, such as MLH1, MSH2, MSH6, or PMS2. Due to their repetitive sequence composition, microsatellite sequences are especially vulnerable. This assay is based on multiplex PCR amplification of 5 microsatellites: BAT-25, BAT-26, MONO-27, NR-21, and NR-24. If there is a difference in the length of a certain microsatellite in the patient’s normal and tumor samples, the microsatellite is considered unstable. If two microsatellite loci (of 5) are unstable, the tumor is designated microsatellite instability high (MSI-H). If only one locus is unstable, the tumor is considered microsatellite instability low (MSI-L), and if no loci are unstable, the tumor is designated microsatellite stable (MSS).

CPT Code

81301

close ORDERING
Preferred Specimen(s)
FFPE tissue, tumor and normal
Container Type
FFPE block for tissue

Volume

REQUESTED VOLUME MINIMUM VOLUME(PEDIATRIC)
Varies Varies

Specimen Stability

Special Handling

Sample should be kept at refrigerator temperatures and arrive in lab within 48 hours of collection. Ship on ice.


close SPECIMEN

Department

Molecular Pathology

Standard Run Time(s)

Weekly

Turnaround Time

ROUTINE STAT
7-14 days 7-14 days

close PROCESSING

Methodology

PCR / Fragment Analysis

close RESULTS