Gene Expression Profiling of Papillary Thyroid Carcinoma Identifies Transcripts Correlated with BRAF Mutational Status and Lymph Node Metastasis

Abstract

Purpose: To identify papillary thyroid carcinoma (PTC)^associated transcripts, we compared the gene expression profiles of three Serial Analysis of Gene Expression libraries generated from thyroid tumors and a normal thyroid tissue. Experimental Design: Selected transcripts were validated in a panel of 57 thyroid tumors using quantitative PCR (qPCR). An independent set of 71 paraffin-embedded sections was used for validation using immunohistochemical analysis. To determine if PTC-associated gene expression could predict lymph node involvement, a separate cohort of 130 primary PTC (54 metastatic and 76 nonmetastatic) was investigated. The BRAF V600E mutational status was compared with qPCR data to identify genes that might be regulated by abnormal BRAF/MEK/extracellular signalregulated kinase signaling. Results: We identified and validated new PTC-associated transcripts. Three genes (CST6, CXCL14, and DHRS3) are strongly associated with PTC. Immunohistochemical analysis of CXCL14 confirmed the qPCR data and showed protein expression in PTC epithelial cells.We also observed that CST6, CXCL14, DHRS3, and SPP1 were associated with PTC lymph node metastasis, with CST6, CXCL14, and SPP1 being positively correlated with metastasis and DHRS3 being negatively correlated. Finally, we found a strong correlation between CST6 and CXCL14 expression and BRAF V600E mutational status, suggesting that these genes may be induced subsequently to BRAF activation and therefore may be downstream in the BRAF/MEK/extracellular signal-regulated kinase signaling pathway. Conclusion: CST6, CXCL14, DHRS3, and SPP1 may play a role in PTC pathogenesis and progression and are possible molecular targets for PTC therapy.

Categorical meta-analysis of Osteopontin as a clinical cancer marker

“…The abundance of Osteopontin in liver cancer was independent of whether cirrhosis was present or not (20)(21)(22)(23). Neither did Osteopontin distinguish B-raf wildtype from B-raf mutant thyroid cancers (24). In multiple myeloma, by contrast, high Osteopontin expression inversely correlated with bone disease and was significantly up-regulated in patients with maf translocations, particularly in the fraction lacking bone disease (25).…”

An update on molecular biology of thyroid cancers

“…Following the activation of the MAPK pathway, secondary molecular events occur, such as hypomethylation and genome-wide hypermethylation, which augment the tumorigenic activity of this pathway [52]. In addition, upregulation of several oncogenic proteins, such as chemokines [53,54], nuclear factor B (NF-B) [55], vascular endothelial growth factor A (VEGFA) [56], matrix metalloproteinases (MMPs) [53,55,57], MET [58,59], vimentin [60], prokineticin 1 (PROK1; also known as EG VEGF) [61], prohibitin [62], hypoxia-inducible factor 1␣ (HIF1␣) [63], thrombospondin 1 (TSP1) [64], urokinase plasminogen activator (uPA) and its receptor (uPAR) [65,66] and transforming growth factor ␤1 (TGF␤1) [67,68] drive cancer cell growth, proliferation and survival, together with tumor angiogenesis, invasion and metastasis.…”

Seven-year follow-up of a juvenile female with papillary thyroid carcinoma with poor outcome, BRAF mutation and loss of expression of iodine-metabolizing genes

“…qPCR reactions were performed in triplicate, the threshold cycle (Ct) was obtained using Applied Biosystem software and was averaged (SD ≤1). Gene expression was normalized using the control gene ribosomal protein S8 as described before (9,12).…”

“…We have previously investigated BRAF mutational status in metastatic and non-metastatic papillary thyroid carcinomas (8,9). We have not only found an association between BRAF-mutation and a more aggressive phenotype but also identifi ed a new BRAF mutation in tree lymph node metastases from PTC (8).…”