Histone H3 Trimethyl K27 Immunostain, Technical Component Only

Casandra

Casandra Test Code MC89461Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID HISMECPT Codes 88341, 88342

Histone H3 Trimethyl K27 Immunostain, Technical Component Only

Clinical Use

Use

The Histone H3 Trimethyl K27 Immunostain is used for the diagnosis of malignant peripheral nerve sheath tumors and diffuse midline gliomas H3 K27M-mutant. Histone H3 trimethyl-K27 is a bivalent epigenetic regulator involved in gene silencing. Evaluation of its expression is particularly useful in diagnosing diffuse midline gliomas, which are more common in children and can also appear in adults, affecting regions like the pons, thalamus, and spinal cord. H3 K27M mutations are marked by global reduction of Histone H3 trimethyl-K27, aiding in distinguishing these tumors from other histologic mimics such as malignant peripheral nerve sheath tumors.

Special Instructions

This test is for the technical performance of the stain only and does not include pathologist interpretation. It should not be ordered alongside a PATHC / Pathology Consultation request, as those will result in cancellation of the IHC stains, which will instead be performed at the reviewing pathologist's discretion with possible additional charges. Specimens must be accompanied by specific labels (green "Attention Pathology" and pink Immunostain Technical Only).

Limitations

Interpretation must be performed by a qualified pathologist within the context of the patient's clinical history and other diagnostic tests. The test does not include pathologist interpretation. Paraffin sections are optimally cut within six weeks as age of sections can affect immunoreactivity. Unsuitable glass slides, due to surface chemistry alterations, can result in inconsistent staining.

Test Details

FDA Approved