TERT Promoter Mutations Are an Independent Predictor of Distant Metastasis in Middle Eastern Papillary Thyroid Microcarcinoma

Development and validation of an interpretable machine learning model for predicting the risk of distant metastasis in papillary thyroid cancer: a multicenter study

Background

The survival rate of patients with distant metastasis (DM) of papillary thyroid carcinoma (PTC) is significantly reduced. It is of great significance to find an effective method for early prediction of the risk of DM for formulating individualized diagnosis and treatment plans and improving prognosis. Previous studies have significant limitations, and it is still necessary to develop new models for predicting the risk of DM of PTC. We aimed to develop and validate interpretable machine learning (ML) models for early prediction of DM in patients with PTC using a multicenter cohort.

Methods

We collected data on patients with PTC who were admitted between June 2013 and May 2023. Data from 1430 patients at Yunnan Cancer Hospital (YCH) served as the training and internal validation set, while data from 434 patients at the First Affiliated Hospital of Kunming Medical University (KMU 1st AH) was used as the external test set. Nine ML methods such as random forest (RF) were used to construct the model. Model prediction performance was compared using evaluation indicators such as the area under the receiver operating characteristic curve (AUC). The SHapley Additive exPlanation (SHAP) method was used to rank the feature importance and explain the final model.

Findings

Among the nine ML models, the RF model performed the best. The RF model accurately predicted the risk of DM in patients with PTC in both the internal validation of the training set [AUC: 0.913, 95% confidence interval (CI) (0.9075-0.9185)] and the external test set [AUC: 0.8996, 95% CI (0.8483-0.9509)]. The calibration curve showed high agreement between the predicted and observed risks. In the sensitivity analysis focusing on DM sites of PTC, the RF model exhibited outstanding performance in predicting "lung-only metastasis" showing high AUC, specificity, sensitivity, F1 score, and a low Brier score. SHAP analysis identified variables that contributed to the model predictions. An online calculator based on the RF model was developed and made available for clinicians at https://predictingdistantmetastasis.shinyapps.io/shiny1/. 11 variables were included in the final RF model: age of the patient with PTC, whether the tumor size is > 2 cm, whether the tumor size is ≤ 1 cm, lymphocyte (LYM) count, monocyte (MONO) count, monocyte/lymphocyte ratio (MLR), thyroglobulin (TG) level, thyroid peroxidase antibody (TPOAb) level, whether the T stage is T1/2, whether the T stage is T3/4, and whether the N stage is N0.

Interpretation

On the basis of large-sample and multicenter data, we developed and validated an explainable ML model for predicting the risk of DM in patients with PTC. The model helps clinicians to identify high-risk patients early and provides a basis for individualized patient treatment plans.

Funding

This work was supported by the National Natural Science Foundation of China (No. 81960426, 82360345 and 82001986), the Outstanding Youth Science Foundation of Yunnan Basic Research Project (No. 202401AY070001-316), Yunnan Province Applied and Basic Research Foundation (No. 202401AT070008), and Ten Thousand Talent Plans for Young Top-notch Talents of Yunnan Province.

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

BACKGROUND

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.

MATERIAL AND METHODS

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®.

RESULTS

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®.

CONCLUSIONS

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

Mortality rate and causes of death in papillary thyroid microcarcinoma

PURPOSE

Papillary thyroid microcarcinoma (PTMC) has an excellent prognosis; however, some PTMCs exhibit poor outcomes. Cancer-specific death from PTMC has been rarely reported, so we aimed to evaluate mortality rates and causes of death in patients who died with PTMC.

METHODS

We retrospectively reviewed 8969 PTMC patients treated at Samsung Medical Center from 1994 to 2017. Mortality rate and causes of death in PTMC patients were evaluated and compared with those of 7873 patients with papillary thyroid carcinoma (PTC) > 1 cm. In addition, we reviewed previous publications reporting cancer-specific deaths from PTMC.

RESULTS

Among the 8969 PTMC patients, 107 (1.2%) patients died. Only two (0.02%) patients have died of PTMC, which was less than the cancer-specific deaths from PTC > 1 cm (0.71%). Among the deceased PTMC patients, 63 (58.9%) died of other malignancies, three (2.8%) died of cardiovascular diseases, and five (4.7%) died of other diseases. Compared with PTC > 1 cm, cancer-specific deaths was less (1.9% vs. 15.1%, P < 0.001), and deaths from other malignancies were higher in deceased PTMC patients (58.9% vs. 30.5%, P < 0.001). According to 18 studies, PTMC-specific mortality rates ranged from 0.05% to 14.3%, and 336 cancer-specific deaths (0.43%) occurred among 78,770 PTMC patients.

CONCLUSION

The cancer-specific mortality rate of PTMC patients was extremely low (0.02%). More than half of deceased PTMC patients died of other malignancies, which was significantly more than those with PTC > 1 cm. These results support that active surveillance can be selected as a therapeutic option for PTMC.

PLK1 and FoxM1 expressions positively correlate in papillary thyroid carcinoma and their combined inhibition results in synergistic anti-tumor effects

Polo-like kinase 1 (PLK1; also known as serine/threonine-protein kinase PLK1) serves as a central player in cell proliferation, exerting critical regulatory roles in mitotic processes and cell survival. We conducted an analysis of PLK1 protein expression in a large cohort of samples from papillary thyroid carcinoma (PTC) patients and examined its functional significance in PTC cell lines, both in vitro and in vivo. PLK1 overexpression was noted in 54.2% of all PTC and was significantly associated with aggressive clinicopathological parameters; it was also found to be an independent prognostic marker for shorter recurrence-free survival. Given the significant association between PLK1 and forkhead box protein M1 (FoxM1), and their concomitant overexpression in a large proportion of PTC samples, we explored their correlation and their combined inhibitions in PTC in vitro and in vivo. Inhibition of PLK1 expression indeed suppressed cell proliferation, leading to cell cycle arrest and apoptosis in PTC cell lines. Significantly, the downregulation of PLK1 reduced the self-renewal capability of spheroids formed from PTC cells. Immunoprecipitation analysis shows that PLK1 binds to FoxM1 and vice versa in vitro. Mechanistically, PLK1 knockdown suppresses FoxM1 expression, whereas inhibition of FoxM1 does not affect PLK1 expression, which suggests that PLK1 acts through the FoxM1 pathway. The combined treatment of a PLK1 inhibitor (volasertib) and a FoxM1 inhibitor (thiostrepton) demonstrated a synergistic effect in reducing PTC cell growth in vitro and delaying tumor growth in vivo. This study highlights the important role of PLK1 in PTC tumorigenesis and prognosis. It also highlights the synergistic therapeutic potential of dual-targeting PLK1 and FoxM1 in PTC, unveiling a potential innovative therapeutic strategy for managing aggressive forms of PTC.

Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution

Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.

Loss of CDH16 expression is a strong independent predictor for lymph node metastasis in Middle Eastern papillary thyroid cancer

Papillary Thyroid Cancer (PTC) is the most common type of thyroid cancer. The membrane-associated glycoprotein cadherin-16 (CDH16) plays a significant role in the embryonal development of thyroid follicles and cell adhesion. Previous studies have indicated a substantial downregulation of CDH16 in PTC. However, its role in Middle Eastern PTC has not been elucidated. We analyzed a tissue microarray comprising 1606 PTC and 240 normal thyroid tissues using immunohistochemistry to assess CDH16 expression and determine its clinico-pathological associations. We also conducted BRAF and TERT mutations analyses through Sanger sequencing. Disease-free survival (DFS) was assessed using Kaplan-Meier curves. CDH16 immunostaining was seen in 100% of normal thyroid tissues but only in 9.4% of PTC tissues (p < 0.0001). The loss of CDH16 expression was associated with aggressive PTC characteristics including bilaterality, multifocality, extrathyroidal extension, tall cell variant, lymph node metastasis (LNM) and distant metastasis. Additionally a correlation between loss of CDH16 expression and BRAF and TERT mutations was identified. Intriguingly, upon conducting multivariate logistic regression analysis, CDH16 was determined to be an independent predictor for LNM (Odds ratio = 2.46; 95% confidence interval = 1.60-3.79; p < 0.0001). Furthermore, CDH16 loss was associated with a shorter DFS (p = 0.0015). However, when we further subdivided CDH16 negative patients based on the co-existence of TERT and/or BRAF mutations, we found that patients with both CDH16 negative expression and TERT mutation exhibited the shortest DFS (p < 0.0001). In conclusion, our results suggest that CDH16 protein expression could serve as a valuable diagnostic tool for PTC. Furthermore, these findings demonstrate that the loss of CDH16 expression is an independent predictor of LNM and may contribute to the aggressiveness of PTC. Therefore, downregulation of CDH16 in PTC might be a potential target for designing novel therapeutic strategies to treat PTC.

Multi-omics profiling of papillary thyroid microcarcinoma reveals different somatic mutations and a unique transcriptomic signature

BACKGROUND

Papillary thyroid microcarcinoma (PTMC) incidence has significantly increased, and some cases still exhibit invasive traits. The entire molecular landscape of PTMC, which can offer hints for the etiology of cancer, is currently absent.

METHODS

We compared our findings with those for PTMC in the TCGA by analyzing the largest study at the current stage of whole exome sequencing and RNA-sequencing data from 64 patients with PTMC. Then, we systematically demonstrated the differences between the two PTMC subtypes based on multi-omics analyses. Additionally, we created a molecular prediction model for the PTMC subtypes and validated them among TCGA patients for individualized integrative assessment.

RESULTS

In addition to the presence of BRAF mutations and RET fusions in the TCGA cohort, we also discovered a new molecular signature named PTMC-inflammatory that implies a potential response to immune intervention, which is enriched with AFP mutations, IGH@-ext fusions, elevated immune-related genes, positive peroxidase antibody, and positive thyroglobulin antibody. Additionally, a molecular prediction model for the PTMC-inflammatory patients was created and validated among TCGA patients, while the prognosis for these patients is poor.

CONCLUSIONS

Our findings comprehensively define the clinical and molecular features of PTMC and may inspire new therapeutic hypotheses.

Brain metastases of papillary thyroid carcinoma origin are derived from aggressive histologic variants and demonstrate similar adverse morphology in the metastatic lesion

BACKGROUND

Distant metastases of papillary thyroid carcinoma are exceedingly rare. We analyzed all cases of brain metastases of papillary thyroid cancer at our institution and performed a literature review over the past ten years to identify histologic and molecular features of primary and metastatic tumors.

METHODS

Following institutional review board approval, the entire pathology archives at our institution were searched for cases of papillary thyroid carcinoma metastatic to brain. Patient demographics, histologic features of both primary and metastatic tumors, molecular information, and clinical outcomes were investigated.

RESULTS

We identified 8 cases of metastatic papillary thyroid carcinoma to brain. The average age at time of diagnosis of metastases was 56.3 years (range: 30-85). Average time from diagnosis of primary thyroid cancer to brain metastasis was 9.3 years (range: 0-24 years). All primary thyroid carcinomas demonstrated aggressive sub-types which were correspondingly seen in brain metastases. Next-generation sequencing revealed the most common mutations were identified in BRAFV600E, NRAS, and AKT1 with one tumor harboring a TERT promoter mutation. Six out of eight patients were deceased at the time of study with an average survival time of 2.3 years (range: 0.17-7 years) following diagnosis of brain metastasis.

CONCLUSIONS

Based on our study, it is highly unlikely that a low-risk variant of papillary thyroid carcinoma will metastasize to the brain. Therefore, careful and accurate reporting of the papillary thyroid carcinoma subtype in primary thyroid tumors is warranted. Certain molecular signatures are associated with more aggressive behavior and worse patient outcomes and next-generation sequencing should be performed on metastatic lesions.

BRAFV600E and TERT promoter C228T mutations on ThyroSeq v3 analysis of delayed skin metastasis from papillary thyroid cancer: a case report and literature review

BACKGROUND

Skin metastasis from papillary thyroid cancer (PTC) is a rare entity that can occur up to decades after treatment of the primary tumor. Here, we present a patient who developed skin metastasis 10 years after treatment of her primary tumor and describe the molecular findings of the metastatic lesion.

CASE PRESENTATION

A 44-year-old female with a history of PTC who underwent a total thyroidectomy and radioactive iodine (RAI) treatment 10 years ago presented with a 1.3-cm skin lesion along the prior thyroidectomy scar. A biopsy revealed metastatic PTC, and the patient underwent surgical excision of the lesion. ThyroSeq molecular testing showed the copresence of BRAF^V600E mutation and TERT promoter C228T mutation. The patient subsequently received one round of adjuvant RAI therapy.

CONCLUSIONS

A high index of suspicion is warranted in patients with a history of PTC who develop a skin lesion, even several years after remission of the primary disease. In patients with high-risk mutations, such as BRAF^V600E and TERT promoter C228T mutations, long-term surveillance of disease recurrence is particularly important.

A Significance of Concomitant BRAFV600E and TERT Mutations in Polish Patients with Papillary Thyroid Microcarcinoma: A Retrospective Cohort Study Based on 430 Cases

Background: The incidence of papillary thyroid cancer is increasing worldwide due to more frequent pathological detection of papillary thyroid microcarcinomas (PTMC), which are cancers measuring 1 cm or less in diameter. In rare cases, the course of PTMC can be aggressive, with an increased risk of recurrence/persistent disease. The aim of this study of Polish patients diagnosed with PTMC was to assess the impact of concomitant B-type Raf kinas-activating mutation in codon 600 of exon 15 (BRAF^V600E) and telomerase reverse transcriptase (TERT) hotspot mutations on clinicopathological features, response to treatment, potential recurrence, and the final outcome. Methods: A retrospective analysis of the 430 PTMC cases diagnosed during 2001-2020 at a single center was performed. All PTMC cases were assessed histopathologically, and analyses of BRAF^V600E and TERT promoter were performed based on DNA isolated from tumor blocks. Results: There were 29/430 (6.7% [confidence interval: 4.6-9.5]) patients in whom the TERT^C228T and/or TERT^C250T mutations coexisted with the BRAF^V600E mutation. A statistical comparison between PTMC cases with concomitant BRAF^V600E and TERT hotspot mutations and those without any of those mutations revealed no significant differences between the two groups with respect to risk stratification, response to primary treatment, clinical course, or final disease status. Conclusion: Regardless of the molecular background of PTMC, the overall response to therapy is excellent, and long-term disease-free survival rates can be achieved by most patients.

Risk Factors for Cervical Lymph Node Metastasis in Middle Eastern Papillary Thyroid Microcarcinoma

Papillary thyroid microcarcinoma (PTMC) typically has an indolent course and excellent prognosis. Nonetheless, a subset of PTMC carries a risk of lymph node metastasis (LNM) and local recurrence. PTC from the Middle Eastern population is unique with respect to demographic and clinico-pathological characteristics as compared to other ethnicities of the world. The risk factors of LNM in PTMC patients of Middle Eastern ethnicity have not been fully explored. The present study aims to investigate the influencing factors of LNM in Middle Eastern PTMC patients and its predictive impact on patient’s outcome. A total of 226 confirmed PTMC cases were selected in this retrospective study. The correlation between clinico-pathological, as well as molecular, characteristics and LNM was evaluated. Multivariate analysis was performed by logistic regression and Cox proportional hazards models. Among the 226 patients, the rate of LNM was 43.8% (99/226). Bilaterality, multifocality, gross extrathyroidal extension (ETE), and intermediate-to-high American Thyroid Association (ATA) risk tumors were significantly associated with LNM in PTMC. Multivariate logistic regression analysis showed that bilaterality and gross ETE were independent predictive factors for LNM in PTMC. The recurrence-free survival (RFS) was shorter in PTMC with LNM compared to those without LNM (p = 0.0051) and was significant on multivariate analysis. In conclusion, our study showed that bilaterality and gross ETE were independent influencing factors of LNM in Saudi patients with PTMC. LNM was also associated with shorter RFS. The identification of risk factors for LNM in patients of Middle Eastern ethnicity could help the individualization of clinical management for PTMC patients.