TERT promoter mutations in thyroid cancer: growing evidence for a predictor of poor outcome

TERT promoter mutations and additional molecular alterations in thyroid fine-needle aspiration specimens: A multi-institutional study with histopathologic follow-up

OBJECTIVES

TERT promoter mutations are not infrequently encountered in thyroid carcinomas; however, it is unclear if additional molecular alterations may play a role in determining tumor behavior.

METHODS

Fine-needle aspiration (FNA) specimens from 32 patients with TERT promoter mutations detected by ThyroSeq v3 from 4 institutions were included in the study. FNA diagnoses, molecular results, and surgical follow-up were retrospectively reviewed and analyzed.

RESULTS

There were 5 benign and 27 malignant neoplasms, including 7 high-grade thyroid carcinomas (HGCs) on histopathologic follow-up. Of 4 cases with an isolated TERT mutation, 3 (75%) cases were malignant. Of 17 cases harboring a co-occurring TERT mutation with 1 additional molecular alteration, 13 (76%) displayed malignancy on histopathologic follow-up. All 11 cases with TERT mutations plus 2 or more additional molecular alterations were malignant on follow-up. Furthermore, HGC was not seen in cases with an isolated TERT mutation, while 80% of cases harboring TERT mutations plus 3 additional molecular alterations showed HGC.

CONCLUSIONS

TERT promoter mutations are commonly associated with malignancy, particularly HGCs, when multiple co-occurring molecular alterations are present. However, TERT promoter mutations may occasionally be detected in benign thyroid neoplasms when encountered in isolation or with fewer than 2 additional molecular alterations.

A retrospective analysis of molecular testing in cytologically indeterminate thyroid nodules with histologic correlation: Experience at a heterogenous multihospital system

INTRODUCTION

Thyroid malignancy is one of the most common types of cancer in developed nations. Currently, fine-needle aspiration cytology (FNAC) is the most practical screening test for thyroid nodules. However, cytologically indeterminate samples comprise approximately 15%-30% of cases. These include cases classified as atypia of undetermined significance (AUS), follicular neoplasm (FN), and suspicious for malignancy (SFM). Indeterminate cases can be sent for molecular testing for more definitive classification to help guide management and prevent overtreatment of benign thyroid nodules. We conducted a retrospective review on molecular testing of indeterminate thyroid FNAC and reviewed subsequent histologic diagnoses in resection specimens to assess how molecular testing supported a diagnosis and its effect on clinical management of patients at our institution.

METHODS

A retrospective chart review was performed on all thyroid FNAC specimens, corresponding molecular testing, and subsequent surgical resection specimens over a 6-year period.

RESULTS

A total of 10,253 thyroid FNAC were performed in our hospital system during our study period, of which 10% (n = 1102/10,253) had indeterminate FNAC results. Molecular testing was performed in 16% (n = 178/1102) of indeterminate cytology cases. Genetic alterations were identified in 39% (n = 69/178) of the cases sent for molecular testing. The majority of cytologically indeterminate cases sent for molecular testing were follicular-patterned lesions and their corresponding resection specimens revealed mostly low grade follicular derived neoplasms (i.e., follicular adenoma, non-invasive follicular thyroid neoplasm with papillary-like nuclear features, and follicular variant of papillary thyroid carcinoma). Of the cases with identified genetic alterations, 75% (n = 52/69) were treated surgically. In cases with no genetic alterations identified, only 18% (n = 20/109) were treated surgically.

DISCUSSION/CONCLUSION

Molecular testing on cytologically indeterminate thyroid nodules can help provide a more accurate risk of malignancy assessment in patients with lesions that are difficult to diagnosis based solely on FNAC morphology. The types of genetic alterations identified in the resected thyroid lesions were consistent with what has been previously described in the literature. Additionally, we found that in the patients with indeterminate thyroid FNAC with adjunct molecular testing, more than half did not undergo surgical resection. This finding emphasizes the value of adding molecular testing in patients, particularly when attempting to reduce unnecessary surgical intervention.

Anaplastic thyroid cancer: Pathogenesis, prognostic factors and genetic landscape (Review)

Anaplastic thyroid cancer (ATC) is a rare and aggressive form of thyroid malignancy, presenting significant challenges in diagnosis and treatment. The rarity of this cancer and its aggressive nature make an accurate diagnosis difficult, requiring a multidisciplinary approach and various imaging techniques. Treatment involves a personalized multimodal approach, including surgery, adjuvant therapies and risk stratification. Prognostic factors such as age, tumor characteristics and genetic alterations play a crucial role in determining patient outcomes. Despite advancements, gaps remain in understanding the underlying mechanisms of the disease and establishing standardized treatment guidelines. Further research, collaborative efforts and multicenter studies are necessary to improve diagnostic accuracy, develop targeted therapies and biomarkers, and enhance the long-term management. The present review provides a comprehensive overview of ATC, discussing its clinical manifestations, diagnostic approaches, treatment options, prognostic factors and genetic landscape.

Transcription Factor Profiling Identifies Spatially Heterogenous Mediators of Follicular Thyroid Cancer Invasion

While minimally invasive follicular thyroid cancer (miFTC) generally has low risk of recurrence or death, encapsulated angioinvasive (eaFTC) or widely invasive (wiFTC) histological subtypes display significantly worse prognosis. Drivers of invasion are incompletely understood. Therefore, tissue samples including miFTC, eaFTC, and wiFTC tumors, as well as histologically normal thyroid adjacent to benign follicular adenomas, were selected from a cohort (n = 21) of thyroid tumor patients, and the gene expression of selected transcription factors was characterized with quantitative PCR. Invasion-relevant spatial expression patterns of selected transcription factors were subsequently characterized with immunohistochemistry. E2F1 was over-expressed in all 3 subtypes (p<0.01). SP1 was differentially expressed in eaFTC and wiFTC compared with normal (p=0.01 and 0.04, respectively). TCF7L2 was significantly upregulated in wiFTC specifically (p<0.05). While these findings were mRNA specific, immunohistochemistry of additional cancer-associated transcription factors revealed differential expression along the tumor invasive front relative to the central tumor, and histone acetylation modulators emerged as putative invasion markers. These findings may have significant implications for the interpretation of bulk gene expression analysis of thyroid tumor samples or for the development of targeted therapeutics for this rare but aggressive thyroid cancer variant.