Genetic mutations, molecular markers and future directions in research

Cross-Talk between Inflammatory Mediators and the Epithelial Mesenchymal Transition Process in the Development of Thyroid Carcinoma

There is strong association between inflammatory processes and their main metabolic mediators, such as leptin, adiponectin secretion, and low/high-density lipoproteins, with the cancer risk and aggressive behavior of solid tumors. In this scenario, cancer cells (CCs) and cancer stem cells (CSCs) have important roles. These cellular populations, which come from differentiated cells and progenitor stem cells, have increased metabolic requirements when it comes to maintaining or expanding the tumors, and they serve as links to some inflammatory mediators. Although the molecular mechanisms that are involved in these associations remain unclear, the two following cellular pathways have been suggested: 1) the mesenchymal-epithelial transition (MET) process, which permits the differentiation of adult stem cells throughout the acquisition of cell polarity and the adhesion to epithelia, as well to new cellular lineages (CSCs); and, 2) a reverse process, termed the epithelial-mesenchymal transition (EMT), where, in pathophysiological conditions (tissue injury, inflammatory process, and oxidative stress), the differentiated cells can acquire a multipotent stem cell-like phenotype. The molecular mechanisms that regulate both EMT and MET are complex and poorly understood. Especially, in the thyroid gland, little is known regarding MET/EMT and the role of CCs or CSCs, providing an exciting, new area of knowledge to be investigated. This article reviews the progress to date in research on the role of inflammatory mediators and metabolic reprogramming during the carcinogenesis process of the thyroid gland and the EMT pathways.

Restoration of p53 using the novel MDM2-p53 antagonist APG115 suppresses dedifferentiated papillary thyroid cancer cells

Dedifferentiated papillary thyroid cancer (DePTC) is characterized by aggressive growth, recurrence, distant metastasis, and resistance to radioactive iodine (RAI) therapy. DePTC is also accompanied by poor prognosis and high early-mortality. Nevertheless, most DePTC cells show intact p53 downstream functionality. In cells with wild-type p53, the murine double minute2 (MDM2) protein interacts with p53 and abrogates its activity. Inhibition of the MDM2-p53 interaction restores p53 activity and leads to cell cycle arrest and apoptosis. Restoring p53 function by inhibiting its interaction with p53 suppressors such as MDM2 is thus a promising therapeutic strategy for the treatment of DePTC. The novel MDM2-p53 interaction antagonist APG115 is an analogue of SAR405838, and is being tested in a phase I clinical trial. In this study, we evaluated the efficacy of APG115 as a single-agent to treat DePTC. APG115 diminished the viability of p53 wild-type DePTC cells and induced cell cycle arrest and apoptosis. In a human xenograft mouse model, APG115 elicited robust tumor regression and cell apoptosis. These data demonstrate that further research is warranted to determine whether APG115 can be used to effectively treat DePTC patients.

Role of hemithyroidectomy in differentiated thyroid cancer

PURPOSE OF REVIEW

The incidence of differentiated thyroid cancer (DTC), especially among small tumors, is increasing worldwide, despite the fact that the mortality rate from thyroid cancer remains stable. Total thyroidectomy with or without radioiodine therapy is actually the standard treatment. In the last 2 decades, several studies have shown that lobectomy could be an alternative to total thyroidectomy in low-risk DTC without compromising overall survival. The aim of this article was to assess the role of conservative surgery (hemithyroidectomy) in DTC reviewing the literature data.

RECENT FINDINGS

Recent advances in diagnostic techniques allow treatment to be tailored to patients' needs. The latest consensus guidelines suggest that patients with high-risk tumors should undergo total thyroidectomy, whereas patients with small, low-risk, node-negative DTC may be candidates for conservative surgery. Careful risk evaluation and stratification makes it possible to individualize treatment, avoid overtreatment and guarantee a good long-term prognosis with low recurrence risk. Excellent prognosis of DTC would require large sample sizes and long-term follow-up for prospective trials comparing the outcomes of total thyroidectomy vs. lobectomy; however, there are several remarkable retrospective studies.

SUMMARY

Based on current clinical data, a conservative surgery might be appropriate for patients with low-risk DTC.

Multikinase inhibitors use in differentiated thyroid carcinoma

Thyroid cancer is the most common endocrine malignancy, and its incidence is increasing. Standard therapy for most patients with localized differentiated thyroid cancer (DTC) includes surgery, radioactive iodine, and thyroid hormone replacement. A minority of thyroid cancer patients requires systemic therapy for metastatic disease. Patients with metastatic DTC do not usually benefit from traditional cytotoxic chemotherapy. In this review, we describe newly developed small-molecule tyrosine kinase inhibitors (TKIs) that are being actively tested and used in the management of advanced thyroid cancer. The use of TKIs as a form of molecular targeted therapy is evolving based on understanding of the pathways involved in DTC. Disrupting tumor vascular supply by targeting vascular endothelial growth factor receptor signaling is the most commonly used approach to treat advanced/metastatic DTC. Other mechanisms include targeting BRAF, MAPK/ERK kinase, or mammalian target of rapamycin signaling. Although TKIs appear to have superior efficacy compared to cytotoxic chemotherapy, they can cause substantial adverse effects; symptomatic management of adverse effects, dose adjustment, or cessation of therapy may be required.

Frequent chromosomal aberrations and candidate genes in head and neck squamous cell carcinoma

The knowledge of the biology of head and neck squamous cell carcinoma (HNSCC) has had relatively little impact on the improvement in oncologic outcome up to date. However, the identification of oncogenes and tumor suppressor genes (TSGs) involved in cancer progression contributes to the understanding of the molecular pathways involved in oncogenesis and could contribute to individual risk assessment and provide tools for improvement of treatment and targets for therapy based on the alterations in these pathways. The aim of this article is to review the chromosomal aberrations commonly found in HNSCC, to identify the genes in these chromosomal regions suggested to act as (candidate) oncogenes or TSGs, and to discuss the molecular mechanisms modulating their expression.

Prognostic biomarkers in thyroid cancer

Thyroid carcinomas represent a challenging problem from the prognostic standpoint. Despite an overall good prognosis of the most frequent endocrine malignancy, 10-15 % of papillary thyroid carcinomas (PTCs) turn refractory to radioactive iodine therapy. The increased incidence of thyroid cancer has led to the search for solid prognostic biomarkers that predict the behaviour of these tumours. Clinical and histopathological prognostic factors remain the only safe elements to be used for diagnosis and prognosis of patients with thyroid tumours. Despite the huge amount of genetic information of thyroid tumours, very few new markers revealed diagnostic or prognostic value per se. BRAF mutation can have some value if associated to other clinico-pathological parameters, or in the particular setting of iodine refractory tumours. Others can prove interesting in the future as predictive biomarkers of therapeutic response, but more studies are needed to confirm these potential biomarkers.