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HelpTest Code PTENC PTEN (SP218), Semi-Quantitative Immunohistochemistry, Manual
Shipping Instructions
Attach the green "Attention Pathology" address label (T498) to the outside of the transport container before putting into the courier mailer.
Necessary Information
A pathology/diagnostic report and a brief history are required.
Specimen Required
Specimen Type: Tissue
Supplies: Pathology Packaging Kit (T554)
Submit:
Formalin-fixed, paraffin-embedded tissue block
OR
3 Unstained glass, "positively charged" slides with 4-microns formalin-fixed, paraffin-embedded tissue
Additional Information: One slide will be stained with hematoxylin and eosin and returned.
Forms
If not ordering electronically, complete, print, and send a Immunohistochemical (IHC)/In Situ Hybridization (ISH) Stains Request (T763) with the specimen.
Useful For
Aiding in detecting PTEN-deficient invasive prostate adenocarcinoma
Method Name
Immunohistochemistry (IHC)
Reporting Name
PTEN (SP218), SemiQuant IHC, ManualSpecimen Type
SpecialSpecimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Special | Ambient (preferred) | |
| Refrigerated | ||
Reject Due To
| Decalcified paraffin embedded tissue | Reject |
| Wet/frozen tissue | Reject |
| Cytology smears | Reject |
| Noncharged slides | Reject |
| ProbeOn slides | Reject |
| Snowcoat slides | Reject |
| Nonformalin fixed tissue, including CytoLyt, SurePath, alcohol-formalin-acetic acid (AFA), 95% ethanol, PREFER and zinc formalin fixatives | Reject |
| Nonparaffin embedded tissue | Reject |
| Broken or cracked unstained slides | Reject |
Clinical Information
The PTEN (SP218) RxDx Assay is indicated as a companion diagnostic to detect and select PTEN-deficient invasive prostate carcinoma patients who may potentially benefit from a combination treatment with capivasertib (TRUQAP).
Clinical cutoff for PTEN loss is greater than or equal to 90% of viable malignant cells with no specific cytoplasmic expression.
Reference Values
An interpretive report will be provided.
Interpretation
The PTEN protein is localized in the cytoplasm and nucleus, and is an essential enzyme expressed in several non-neoplastic tissues. The PTEN (SP218) RxDx Assay is indicated as a companion diagnostic to aid in identifying patients who may be eligible for treatment with TRUQAP (capivasertib). Clinical cutoff for PTEN loss is greater than or equal to 90% of viable malignant cells with no specific cytoplasmic expression. Nuclear expression in viable malignant cells should be disregarded.(1)
Cautions
This test has been validated for non-decalcified paraffin-embedded tissue specimens fixed in 10% neutral buffered formalin at Mayo Clinic in Rochester, Minnesota. Specimens are recommended to be placed in formalin within 1 hour of acquisition and fixed between 6 hours and 72 hours. This assay has not been validated on tissue or cellblocks subjected to alternative fixatives or decalcification.
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.
The charge of glass slides can be affected by environmental factors and subsequently may alter slide staining. Sending unsuitable glass slides can result in inconsistent staining due to poor slide surface chemistry.
Best practices for storage of positively charged slides:
-Minimize time slides are stored after being unpackaged
-Limit exposure to high humidity and heat
-Minimize exposure to plastics
Broken or cracked unstained slides are not compatible with the instrumentation used in our performing laboratories and will be rejected. Additional material may be requested.
Clinical Reference
1. Ventana PTEN (SP218) RxDx Assay Data Sheet. Roche Diagnostics; 1019742US, 02/01/2026
2. Jamaspishvili T, Berman DM, Ross AE, et al. Clinical implications of PTEN loss in prostate cancer. Nat Rev Urol. 2018;15(4):222-234
3. Shah RB, Shore KT, Yoon J, Mendrinos S, McKenney JK, Tian W. PTEN loss in prostatic adenocarcinoma correlates with specific adverse histologic features (intraductal carcinoma, cribriform gleason pattern 4 and stromogenic carcinoma). Prostate. 2019;79(11):1267-1273
4. Fizazi K, Clarke NW, De Santis M, et al. Capivasertib plus abiraterone in PTEN-deficient metastatic hormone-sensitive prostate cancer: CAPItello-281 phase III study. Ann Oncol. 2026;37(1):53-68. doi:10.1016/j.annonc.2025.10.004
Method Description
Immunohistochemical staining and detection of PTEN (SP218) is performed in formalin-fixed, paraffin-embedded tissue sections using the VENTANA PTEN (SP218) RxDx Assay. The 4-micron tissue sections are deparaffinized, subjected to heat-induced antigen retrieval and peroxidase inhibitor, incubated with a rabbit monoclonal antibody (SP218), and visualized using a proprietary kit detection system. Sections are counterstained with hematoxylin and post counterstained with bluing. Stained slides are examined microscopically by the consulting anatomic pathologist.(Package insert: VENTANA PTEN [SP218] RxDx Assay. Ventana Medical Systems, Inc; 1019742US, 02/01/2026)
Day(s) Performed
Monday through Friday
Report Available
5 to 7 daysSpecimen Retention Time
Until reportedPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88360
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PTENC | PTEN (SP218), SemiQuant IHC, Manual | 81706-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 624278 | Interpretation | 59465-5 |
| 624287 | Participated in the Interpretation | No LOINC Needed |
| 624288 | Report electronically signed by | 19139-5 |
| 624289 | Material Received | 81178-6 |
| 624290 | Disclaimer | 62364-5 |
| 624291 | Case Number | 80398-1 |