Thyroid Fine Needle Aspiration Biopsies in Children: Study of Cytological-Histological Correlation and Immunostaining with Thyroid Peroxidase Monoclonal Antibodies

A potential biomarker hsa-miR-200a-5p distinguishing between benign thyroid tumors with papillary hyperplasia and papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common endocrine cancer with a significantly increase of the incidence recently. Several cytokines, such as thyroid peroxidase (TPO), cluster of differentiation 56 (CD56), Galectin-3, mesothelial cell (MC), cytokeratin 19 (CK19) and BRAF (B-raf) were recommended to be tested by immunohistochemistry (IHC) for a definitive diagnosis, but were still limited in clinical use because of their relative lower sensitivity and specificity. MicroRNA (miRNA), as a new molecular biomarkers, however, has not been reported yet so far. To address this, hsa-miR-200a-5p, a miRNA, was selected and detected in PTC patients by in situ hybrization with benign thyroid tumor with papillary hyperplasia as a control, and the differential expression of hsa-miR-200a-5p between fresh PTC tissues and control was detected by qRT-PCR. Expressive levels of cytokines of TPO, CD56, Galectin-3, MC, CK19 and B-raf were also detected by immunohistochemistry. The correlation was analyzed by SPSS software using Spearman methods. As expected, the hsa-miR-200a-5p expressive level was significantly increased in PTC patients, compared to that of control, and was consistent with that of TPO, CD56, Galectin-3, MC, CK19 and B-raf. In addition, expression of hsa-miR-200a-5p showed negative correlation to that of TPO (rs = - 0.734; **: P < 0.01) and CD56 (rs = - 0.570; **: P < 0.01), but positive correlation to that of Galectin-3 (rs = 0.601; **: P < 0.01), MC (rs = 0.508; **: P < 0.01), CK19 (rs = 0.712; **: P < 0.01) and B-raf (rs = 0.378; **: P < 0.01). PTC and papillary benign thyroid papillary hyperplasia are difficult to distinguish in morphology, so requiring immunohistochemistry to further differentiate the diagnosis, however, for the existing clinical common diagnostic marker for immunohistochemistry, the sensitivity and accuracy are low, it is easy to miss diagnosis. Therefore, there is an urgent need for a rapid and sensitive molecular marker. So miR-200a-5p can be used to assist in the diagnosis of PTC at the molecular level, and as a biomarker, can be effectively used to distinguish between PTC and benign thyroid tumor with papillary hyperplasia.

Cytomorphological and molecular genetic findings in pediatric thyroid fine-needle aspiration

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology is largely based on data from adult studies. Although thyroid nodules in children are rare, the rate of malignancy is high. The authors' aim was to analyze the cytomorphology and mutational profiles in pediatric thyroid fine-needle aspirations (FNAs).

METHODS

Thyroid FNAs from patients 21 years old or younger were identified from the authors' pathology archive, categorized using the Bethesda System for Reporting Thyroid Cytopathology, and correlated with histological and molecular follow-up.

RESULTS

A total of 179 samples from 142 patients were identified, including 96 cases (54%) with histological follow-up and 66 cases (37%) with molecular data. The diagnoses included 21 (12%) unsatisfactory, 82 (46%) negative, 43 (24%) atypia or follicular lesion of undetermined significance, 19 (11%) suspicious for follicular neoplasm, 6 (3%) suspicious for malignancy, and 8 (4%) positive for malignancy. The rate of malignancy in each category was 0%, 7%, 28%, 58%, 100%, and 100%, respectively. Of the 66 FNAs with molecular data, there were 11 (17%) positive for mutations. All mutation-positive FNAs were papillary thyroid carcinomas (PTCs) on resection. The overall sensitivity and specificity in this population were 80% and 100%, respectively.

CONCLUSIONS

This study demonstrates that thyroid FNA in children is a sensitive and highly specific tool. There was a 17% positivity rate for a genetic mutation, which correlated with malignancy in all cases. In comparison to adults, there was a higher prevalence of RET/PTC mutations and lower prevalence of BRAF mutations, which may in part explain the less aggressive nature of PTCs reported in children.

Update on the molecular signature of differentiated thyroid cancer: clinical implications and potential opportunities

With the development and maturation of new technologies, there has been a steady incorporation of powerful new tools into the evaluation and management of thyroid nodules and thyroid cancer. An increasing number of reports on oncogene testing and molecular screening in fine-needle aspiration biopsy samples have been published. However, there remains a paucity of data and consensus on combining both conventional and molecular technologies to determine the diagnosis and/or prognosis of disease. All patients with differentiated thyroid cancer stand to benefit from the identification and incorporation of reliable molecular markers into clinical practice. Identification of reliable markers would allow for stratification of treatment, affording the medical and surgical teams an ability to individually tailor evaluation and treatment, applying aggressive therapy and monitoring only when clinically warranted. For the majority of patients with thyroid cancer, the incorporation of a validated, multifaceted molecular profiling system may not improve survival; however, there is great opportunity for these efforts to decrease the morbidity associated with our current approach.

TSH compensates thyroid-specific IGF-I receptor knockout and causes papillary thyroid hyperplasia

Although TSH stimulates all aspects of thyroid physiology IGF-I signaling through a tyrosine kinase-containing transmembrane receptor exhibits a permissive impact on TSH action. To better understand the importance of the IGF-I receptor in the thyroid in vivo, we inactivated the Igf1r with a Tg promoter-driven Cre-lox system in mice. We studied male and female mice with thyroidal wild-type, Igf1r(+/-), and Igf1r(-/-) genotypes. Targeted Igf1r inactivation did transiently reduce thyroid hormone levels and significantly increased TSH levels in both heterozygous and homozygous mice without affecting thyroid weight. Histological analysis of thyroid tissue with Igf1r inactivation revealed hyperplasia and heterogeneous follicle structure. From 4 months of age, we detected papillary thyroid architecture in heterozygous and homozygous mice. We also noted increased body weight of male mice with a homozygous thyroidal null mutation in the Igf1r locus, compared with wild-type mice, respectively. A decrease of mRNA and protein for thyroid peroxidase and increased mRNA and protein for IGF-II receptor but no significant mRNA changes for the insulin receptor, the TSH receptor, and the sodium-iodide-symporter in both Igf1r(+/-) and Igf1r(-/-) mice were detected. Our results suggest that the strong increase of TSH benefits papillary thyroid hyperplasia and completely compensates the loss of IGF-I receptor signaling at the level of thyroid hormones without significant increase in thyroid weight. This could indicate that the IGF-I receptor signaling is less essential for thyroid hormone synthesis but maintains homeostasis and normal thyroid morphogenesis.