Thyroid cancer molecular signaling pathways and use of targeted therapy

Carcinoma de tiroides: Descripción de 634 pacientes atendidos en el Hospital Universitario San Ignacio, Bogotá, D.C., Colombia

Introducción. La incidencia del carcinoma de tiroides ha aumentado a nivel mundial, probablemente relacionado con el sobre diagnóstico de nódulos tiroideos asintomáticos. La alta sobrevida del carcinoma diferenciado de tiroides ha permitido posibilidades de manejo quirúrgico menos radicales, o inclusive, la vigilancia activa de tumores seleccionados. Existen reportes de características clínico-patológicas del carcinoma de tiroides de nuestro país distintas a las reportadas en la literatura internacional. Métodos. Estudio observacional descriptivo de una cohorte retrospectiva de pacientes con carcinoma de tiroides atendidos en un hospital universitario entre 2015 y 2020. Resultados. Se identificaron 634 pacientes, el 83,4 % de sexo femenino. La tiroidectomía total con vaciamiento central fue el procedimiento más realizado (86,7 %). De 613 carcinomas diferenciados de tiroides, el 94,2 % corresponden al tipo papilar, seguido por el carcinoma de células de Hürtle (1,6 %); el 26,2 % presentaron subtipos histológicos agresivos y el 28,4 % compromiso tumoral bilateral. En los vaciamientos centrales se encontró 58,7 % de enfermedad metastásica; que fue de 49 % en los pacientes con microcarcinomas papilares (19 %). De las 68 lesiones del nervio laríngeo recurrente, 47 % fueron por secciones oncológicas. Discusión. En nuestra serie, la proporción de pacientes con carcinoma papilar de tiroides y de sus variantes histológicas agresivas, así como el compromiso tumoral bilateral es mayor a lo reportado en la literatura científica. Conclusión. El comportamiento biológico del carcinoma de tiroides es variable y puede tener características diferentes entre regiones; el manejo en nuestro medio debería considerar las características propias de nuestra población.

Heat shock proteins HSP90, HSP70 and GRP78 expression in medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma management consists mainly of surgical resection and is largely chemoresistant. There is ongoing effort to discover novel therapies for medullary thyroid carcinoma. Increased levels of heat shock proteins have been associated with multiple cancers and are being studied as potential therapeutic targets. The purpose of this study was to determine the expression levels of heat shock proteins 90 and 70 and of glucose related protein 78 in medullary thyroid carcinoma tissues compared with normal thyroid tissues.

METHODS

20 tissue specimens of medullary thyroid carcinoma and 10 specimens of thyroids without malignancy were analyzed by immunohistochemistry.

RESULTS

Medullary thyroid carcinoma specimens showed 27% higher expression level of heat shock protein 90 immunostaining, and a 43% higher expression level of heat shock protein 70 immunostaining versus normal controls. These differences, however, were not statistically significant. A significantly higher expression level was noted for glucose related protein 78 in the medullary thyroid carcinoma specimens than in the controls.

CONCLUSION

This study indicates increased expression levels of heat shock proteins 90 and 70 and glucose related protein 78 levels in medullary thyroid carcinoma. These findings, though preliminary imply that these proteins may have a role in medullary thyroid carcinoma's tumor biology and may have and future therapeutic options. Larger cohorts are needed to corroborate these results.

Prognostic factors and follow-up of patients with differentiated thyroid carcinoma with false negative or nondiagnostic FNAC before surgery. Comparison with a control group

Since the clinical implementation of fine needle aspiration cytology (FNAC) to diagnose thyroid carcinoma, few patients remain misdiagnosed and little is known about their clinical outcomes. An observational retrospective study was carried out to analyse prognostic factors and follow-up of patients with differentiated thyroid carcinoma (DTC) not disclosed by FNAC before surgery, compared to a control group. From October 2003 to July 2010, 308 patients underwent surgery as treatment for nodular goitre and 53 had DTC. Cases were 12 subjects with DTC and benign (n = 7) or nondiagnostic (n = 5) FNAC. Controls were 39 subjects with DTC and suspicious (n = 19) or malignant (n = 20) FNAC. Prognostic factors, recurrence and survival rates were compared. Cases had longer time from FNAC to surgery than the control group (86.8 ± 74.1 vs. 16.4 ± 23.8 weeks; P < 0.001), higher prevalence of follicular carcinoma (33.3 vs. 2.6%; P = 0.009), and of two-time total thyroidectomy (75 vs. 30.8%; P = 0.016). Average follow-up was 42.7 ± 25.3 months (2-86 months). There were no deaths. Disease-free survival for cases was 66.9 ± 5.8 months, and for controls 78.7 ± 3.9 months (P: ns). In patients with DTC, the result of the FNAC performed before surgery was not an independent predictor of recurrences or mortality in the first 7 years of follow-up. Thus, false negative or nondiagnostic FNAC in a patient with DTC does not seem to be a primary prognostic factor, but it may reveal other adverse prognostic factors such as longer time to therapy and higher prevalence of follicular carcinoma that may influence long-term outcomes.

Emerging therapeutics for advanced thyroid malignancies: rationale and targeted approaches

INTRODUCTION

Thyroid cancer is an emerging public health concern. In the USA, its incidence has doubled in the past decade, making it the eighth most commonly diagnosed neoplasm in 2010. Despite this alarming increase, most thyroid cancer patients benefit from conventional approaches (surgery, radioiodine, radiotherapy, TSH suppression with levothyroxine) and are often cured. Nevertheless, a minority have aggressive tumors resistant to cytotoxic and other historical therapies; these patients sorely need new treatment options.

AREAS COVERED

Herein the biology and molecular characteristics of the common histological types of thyroid cancer are reviewed to provide context for subsequent discussion of recent developments and emerging therapeutics for advanced thyroid cancers.

EXPERT OPINION

Several kinase inhibitors, especially those targeting VEGFR and/or RET, have already demonstrated promising activity in differentiated and medullary thyroid cancers (DTC, MTC). Although of minimal benefit in DTC and MTC, cytotoxic chemotherapy with anti-microtubule agents and/or anthracyclines in combination with intensity-modulated radiation therapy appears to extend survival for patients with locoregionally confined anaplastic thyroid cancer (ATC), but to have only modest benefit in metastatic ATC. Further discovery and development of novel agents and combinations of agents will be critical to further progress in treating advanced thyroid cancers of all histotypes.

Standard and emerging therapies for metastatic differentiated thyroid cancer

Differentiated thyroid cancer accounts for >90% of cases of thyroid cancer, with most patients having an excellent prognosis. Distant metastases occur in 10%-15% of patients, decreasing the overall 10-year survival rate in this group to 40%. Radioactive iodine has been the mainstay of treatment for distant metastases, with good results when lesions retain the ability to take up iodine. For patients with metastatic disease resistant to radioactive iodine, treatment options are few and survival is poor. Chemotherapy and external beam radiotherapy have been used in these patients, but with disappointing results. In recent years, our understanding of the molecular pathways involved in thyroid cancer has increased and a number of molecular targets have been identified. These targets include the proto-oncogenes BRAF and RET, known to be common mutations in thyroid cancer; vascular endothelial growth factor receptor and platelet-derived growth factor receptor, associated with angiogenesis; and the sodium-iodide symporter, with the aim of restoring its expression and hence radioactive iodine uptake. There are now multiple trials of tyrosine kinase inhibitors, angiogenesis inhibitors, and other novel agents available to patients with metastatic thyroid cancer. This review discusses both traditional and novel treatments for metastatic differentiated thyroid cancer with a particular focus on emerging treatments for patients with radioactive iodine-refractory disease.

Partial remission of metastatic papillary thyroid carcinoma with sunitinib. Report of a case and review of the literature

Tyrosine kinase receptors have been implicated in thyroid cancer. Therefore, tyrosine kinase inhibitors may be used for the treatment of advanced metastatic thyroid carcinoma. The aim is to present a case of metastatic papillary thyroid carcinoma responding to the administration of sunitinib, a multi-targeted protein kinase inhibitor. A patient presented with metastatic papillary thyroid carcinoma and hyperthyroidism. After euthyroidism was achieved the patient was treated by the administration of therapeutic radioiodine (131)I, radiotherapy and sunitinib, a multi-targeted tyrosine kinase inhibitor. Thyroglobulin levels decreased from 9,594 to 6,816 ng/ml after 1 month, 6 months later being 2,776 ng/ml. The lesion in the pelvis was 12.5 × 9 cm before treatment decreasing thereafter and the patient improved clinically. The administration of sunitinib resulted in partial disease response in a patient with progressive metastatic papillary thyroid carcinoma. Protein kinase inhibitors may prove useful in the management of advanced metastatic papillary thyroid carcinoma.

Expression of opioid growth factor (OGF)-OGF receptor (OGFr) axis in human nonmedullary thyroid cancer

BACKGROUND

Although thyroid cancers are readily treatable with surgery and radioactive iodine, there are problems in managing recurring, as well as locally advanced, thyroid cancer. The opioid growth factor (OGF) and its receptor, OGF receptor (OGFr), form a tonically active, autocrine-paracrine loop that serves to inhibit cell proliferation in a wide variety of normal and abnormal cells and tissues. In the present study we examined the presence and distribution of OGF and OGFr in nonmedullary thyroid cancer, including papillary, follicular, and anaplastic, as well as thyroid tissue from patients with nonmalignant disease.

METHODS

Patient samples of thyroid cancers and goiter were collected at the time of resection and processed for immunohistochemistry of OGF and OGFr, as well as pharmacological binding assays for OGFr.

RESULTS

Both peptide and receptor were detected in the cytoplasm and nucleus of all nonmedullary thyroid cancers, as well as in goiter. Specific and saturable binding of OGFr was found in all thyroid samples.

CONCLUSIONS

The finding that a potent negative growth regulator and its receptor are present in nonmedullary thyroid cancers and thyroid tissues from patients with nonmalignant disease lead us to suggest that the OGF-OGFr axis serves as a regulator of cell proliferation in these tissues. Moreover, modulation of this biological system may be used to treat progression of nonmedullary thyroid neoplasias.