Genetic Testing · Thyroid Nodules
mir-THYpe Molecular Testing for Thyroid Nodules
A microRNA and gene-mutation classifier used to help clarify whether an indeterminate thyroid nodule is more likely benign or suspicious for cancer — used at PACSO to support surgical decision-making alongside standard cytology.
What is mir-THYpe?
Around 20–30% of thyroid fine-needle aspiration (FNA) biopsies come back “indeterminate” (Bethesda category III or IV) — not clearly benign or malignant on cytology alone. Historically, many patients in this category were referred for diagnostic surgery simply to get a definitive answer, even though most indeterminate nodules turn out to be benign.
mir-THYpe analyses the existing FNA sample for a microRNA expression signature together with BRAF V600E and TERT promoter mutation status, using a validated algorithm to classify the nodule as molecular “positive” (higher risk, favouring surgery) or “negative” (lower risk, favouring continued monitoring). It is intended to be used alongside — not instead of — your surgeon’s clinical judgement.
How the test works
No new biopsy is required — the test runs on the sample already taken during your FNA.
Existing sample used
The test uses the FNA slide already collected during your biopsy — no repeat needle procedure.
Sample sent to the lab
Your sample is sent to Onkos Diagnósticos Moleculares, the specialist laboratory in Brazil that performs mir-THYpe.
Molecular analysis
The lab profiles microRNA expression and screens for BRAF V600E and TERT promoter mutations.
Result reviewed with you
Your PACSO surgeon reviews the result with you and discusses what it means for next steps.
Clinical performance
Figures below are from a real-world, prospective, multicentre validation study of the mir-THYpe classifier (Santos et al., eBioMedicine / The Lancet, 2022; 435 patients, 440 Bethesda III/IV nodules).
of all surgeries in the study population were avoided using the test result to guide decisions.
of surgeries considered potentially unnecessary (i.e. for nodules that proved benign) were prevented.
92.3%
of clinical decisions in the study were directly supported by the test result.
When is this test recommended?
- Your FNA cytology result is Bethesda category III (AUS/FLUS) or IV (follicular/Hürthle cell neoplasm) — the “indeterminate” categories.
- Selected Bethesda V (suspicious for malignancy) cases, at your surgeon’s discretion.
- You and your surgeon are weighing surgery against continued monitoring and want additional information to guide that decision.
Benefits over cytology alone
- Uses the FNA sample you’ve already given — no repeat needle biopsy.
- Can help avoid diagnostic surgery for nodules that are very likely benign.
- Where surgery is indicated, helps inform how extensive it needs to be.
- Validated in a large, real-world multicentre study (see above).
South African availability & procedure
PACSO has a special arrangement with Onkos (Brazil) to perform this test. Once a patient is referred to or discussed with PACSO, and permission is granted to access the relevant radiology and pathology results for the thyroid nodule, the case is reviewed by our expert team.
If the team is satisfied that mir-THYpe would be an appropriate option for the patient, the cytology slides are requested from the pathology lab where the cytology was originally reported. An expert head-and-neck pathologist then assesses the slides to confirm they contain an adequate number of cells and that the Bethesda classification is suitable for further testing.
Once this central review is complete, the slides are couriered to Brazil for the mir-THYpe test. Final results are typically available two to three weeks after arrival.
Cost considerations
- Unfortunately, none of the medical aids in South Africa will cover the test, even though it will save them money in avoiding unnecessary surgery.
- The cost is ~US$1,000
- Once the specimen arrives in Brazil, you will receive an email with a payment link and you can settle the fee with your credit card.
Alternatives to consider
mir-THYpe is one option among several ways to approach an indeterminate nodule — your surgeon can talk through which fits your situation.
Repeat FNA / continued monitoring
Ultrasound surveillance with a repeat biopsy if the nodule changes, without molecular testing.
Diagnostic lobectomy
Surgical removal of the nodule/lobe to obtain a definitive histological diagnosis directly.
Other molecular classifiers
Tests such as Afirma GSC (Veracyte, USA) or ThyroSeq use different methods and are available in some markets.
Questions to ask your doctor
- Is my nodule a good candidate for mir-THYpe, or would another approach be more appropriate?
- Which mir-THYpe panel would be used for my sample, and why?
- What does a “positive” or “negative” result actually change about my treatment plan?