Home
HelpTest ID HISME Histone H3 Trimethyl K27 Immunostain, Technical Component Only
Ordering Guidance
This test includes only technical performance of the stain (no pathologist interpretation is performed). If diagnostic consultation by a pathologist is required order PATHC / Pathology Consultation.
Shipping Instructions
Attach the green "Attention Pathology" address label (T498) and the pink Immunostain Technical Only label included in the kit to the outside of the transport container.
Specimen Required
Supplies: Immunostain Technical Only Envelope (T693)
Specimen Type: Tissue
Container/Tube: Immunostain Technical Only Envelope
Preferred: 2 Unstained positively charged glass slide (25- x 75- x 1-mm) per test ordered; sections 4-microns thick
Acceptable: Formalin-fixed, paraffin-embedded tissue block
Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.
Secondary ID
72127Useful For
Diagnosis of malignant peripheral nerve sheath tumors and diffuse midline gliomas H3 K27M-mutant
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IHTOI | IHC Initial, Tech Only | No | No |
| IHTOA | IHC Additional, Tech Only | No | No |
Testing Algorithm
For the initial technical component only immunohistochemical (IHC) stain performed, the appropriate bill-only test ID will be reflexed and charged (IHTOI). For each additional technical component only IHC stain performed, an additional bill-only test ID will be reflexed and charged (IHTOA).
Method Name
Immunohistochemistry (IHC)
Reporting Name
Histone3 K27me3 IHC, Tech OnlySpecimen Type
TECHONLYSpecimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| TECHONLY | Ambient (preferred) | |
| Refrigerated | ||
Clinical Information
Histone H3 trimethyl-K27 is a bivalent epigenetic regulator that silences or represses the gene. Evaluation of H3 trimethyl-K27 immunohistochemical expression is a helpful biomarker in the diagnosis of diffuse midline gliomas H3 K27M-mutant, which most frequently occur in children and with less frequency in adults. These tumors typically occur along the midline and include intrinsic pontine gliomas (DIPG), thalamic, and spinal cord diffuse gliomas. H3 K27M mutations lead to global reduction in H3 trimethyl-K27 and result in H3 trimethyl-K27 loss of expression.
Histologic mimics can be distinguishable from malignant peripheral nerve sheath tumors that show H3 trimethyl-K27 loss of expression.
Cautions
Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen dependent. Best practice is for paraffin sections to be cut within 6 weeks.
Day(s) Performed
Monday through Friday
Report Available
1 to 3 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
88342-TC, primary
88341-TC, if additional IHC