Shifted termination assay (STA) fragment analysis to detect BRAF V600 mutations in papillary thyroid carcinomas

The changing characteristics and molecular profiles of papillary thyroid carcinoma over time: a systematic review

BACKGROUND

The genetic alterations of papillary thyroid carcinoma (PTC) have been reported to change over the past few decades. We performed this systematic review to further examine the trends and modifications of patient demographic, clinicopathological features and molecular profiles of PTC over time.

METHODS

A literature search was performed within six electronic databases to identify relevant articles. The inclusion criteria were published studies investigating BRAF mutations, RET/PTC rearrangements or RAS mutations in PTCs or classical PTCs. Two teams of reviewers independently screened titles and abstracts of all articles. Full texts of potential articles were read and extracted data were listed and stratified into an excel file according to country, city, institution, and surgical time period. Student t test and Pearson Chi-square were used to analyze the trends of demographic and clinicopathological features of PTC patients and the prevalence of each genetic alteration in individual institutions.

RESULTS

From 3139 articles, we included 16 articles for final analysis. Our results showed an increasing trend of BRAF and a decreasing trend of RET/PTC prevalence over time in PTCs and classical PTCs, accompanied by an older age of PTC patients, an increase in proportion of PTMC and less aggressive behaviours of tumours.

CONCLUSIONS

The demographic and clinicopathological characteristics and molecular profile of PTCs have been changing over the past few decades. These modifications suggest changes in etiologies and risk factors of thyroid cancer that influence the tumorigenesis of PTCs.

A novel approach for the detection and genetic analysis of live melanoma circulating tumor cells

Background

Circulating tumor cell (CTC) detection and genetic analysis may complement currently available disease assessments in patients with melanoma to improve risk stratification and monitoring. We therefore sought to establish the feasibility of a telomerase-based assay for detecting and isolating live melanoma CTCs.

Methods

The telomerase-based CTC assay utilizes an adenoviral vector that, in the presence of elevated human telomerase activity, drives the amplification of green fluorescent protein. Tumor cells are then identified via an image processing system. The protocol was tested on melanoma cells in culture or spiked into control blood, and on samples from patients with metastatic melanoma. Genetic analysis of the isolated melanoma CTCs was then performed for BRAF mutation status.

Results

The adenoviral vector was effective for all melanoma cell lines tested with sensitivity of 88.7% (95%CI 85.6-90.4%) and specificity of 99.9% (95%CI 99.8-99.9%). In a pilot trial of patients with metastatic disease, CTCs were identified in 9 of 10 patients, with a mean of 6.0 CTCs/mL. At a cutoff of 1.1 CTCs/mL, the telomerase-based assay exhibits test performance of 90.0% sensitivity and 91.7% specificity. BRAF mutation analysis of melanoma cells isolated from culture or spiked control blood, or from pilot patient samples was found to match the known BRAF mutation status of the cell lines and primary tumors.

Conclusions

To our knowledge, this is the first report of a telomerase-based assay effective for detecting and isolating live melanoma CTCs. These promising findings support further studies, including towards integrating into the management of patients with melanoma receiving multimodality therapy.

Past, current and future approaches to querying MAPK pathway activation: status and clinical implications

MAPK pathway activation related to cancer development has drawn a great deal of attention in the field of personalized medicine in recent years. Many different approaches and assays have been developed to query the activation of this pathway and to develop life-saving treatments. The goal of this review article is threefold. First, to provide a brief overview of the many mutation assays that have been used to detect MAPK pathway activation, and to compare pros and cons of these assay platforms. Second, to focus on one custom-designed multiplexing mutation assay that is currently used to support an ongoing clinical trial and to show the novel features of this assay and its relevance in addressing unmet clinical needs. Third, to provide future perspectives of these MAPK pathway gene mutation detection efforts and to suggest how what we have learned from past and current approaches should guide future developments.

Analysis of BRAF(V600E) mutation and DNA methylation improves the diagnostics of thyroid fine needle aspiration biopsies

BACKGROUND

Thyroid nodules with indeterminate cytological features on fine needle aspiration biopsy specimens (FNABs) have a ~20% risk of thyroid cancer. BRAF(V600E) mutation and DNA methylation are useful markers to distinguish malignant thyroid neoplasm from benign. The aim of this study was to determine whether combined detection of BRAF(V600E) mutation and methylation markers on FNABs could improve the diagnostic accuracy of thyroid cancer.

METHODS

Using pyrosequencing and quantitative methylation-specific PCR (Q-MSP) methods, FNABs from 79 and 38 patients with thyroid nodules in training and test groups, respectively, were analyzed for BRAF(V600E) mutation and gene methylation.

RESULTS

BRAF(V600E) mutation was found in 30/42 (71.4%) and 14/20 (70%) FNABs in training and test groups, respectively. All BRAF(V600E)-positive samples were histologically diagnosed as papillary thyroid cancer (PTC) after thyroidectomy. As expected, BRAF mutation was not found in all benign nodules. Moreover, we demonstrated that the five genes, including CALCA, DAPK1, TIMP3, RAR-beta and RASSF1A, were aberrantly methylated in FNABs. Of them, methylation level of DAPK1 in PTCs was significantly higher than that in benign samples (P <0.0001). Conversely, methylation level of RASSF1A in PTCs was significantly lower than that in benign samples (P =0.003). Notably, compared with BRAF mutation testing alone, combined detection of BRAF mutation and methylation markers increased the diagnostic sensitivity and accuracy of PTC with excellent specificity.

CONCLUSION

Our data have demonstrated that combine analysis of BRAF mutation and DNA methylation markers on FNABs may be a useful strategy to facilitate the diagnosis of malignant thyroid neoplasm, particularly PTC.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6080878071149177.