# TERT RNAscope analysis of sub-centimetric papillary thyroid carcinomas and synchronous lymph node metastases

## TL;DR

This study examines the role of TERT RNA in small thyroid cancers and their lymph node metastases, finding no TERT expression in metastases.

## Contribution

The study provides new evidence that TERT expression is not involved in early lymph node metastasis in small papillary thyroid carcinomas.

## Key findings

- TERT RNA expression was not detected in lymph node metastases using RNAScope®.
- Primary tumors and metastases showed low Ki-67 proliferation indices and wild-type p53 status.
- Morphological patterns were heterogeneous in both primary tumors and metastases.

## Abstract

Sub-centrimetric papillary thyroid carcinomas usually have a good prognosis with a cancer specific survival of > 99%, however in up to 65% of patients, lymph node metastases can be observed. Molecular alterations in BRAF, TERT and TP53 are associated with worse clinicopathological outcome in patients with papillary thyroid carcinoma.

Twenty-two cases of papillary thyroid carcinomas measuring ≤ 1 cm with synchronous lymph node metastases were examined regarding morphological patterns and immunohistochemical status of p53, Ki-67, and BRAF V600E status. TERT RNA expression in lymph node metastases were evaluated by RNAScope®.

Morphological patterns were heterogeneous in both primary tumors and lymph node metastases. Proliferation indices measured by Ki-67 were low. Both primary and lymph node metastases were wild type for p53 by immunohistochemical analysis. No lymph node metastasis showed TERT expression by RNAScope®.

Our data indicate that TERT expression is not involved in the development early lymph node metastasis in patients with sub-centimetric PTC.

The online version contains supplementary material available at 10.1186/s13044-024-00195-7.