Project description:Although fine needle aspiration (FNA) cytology is helpful in determining whether thyroid nodules are benign or malignant, this distinction remains challenging in follicular neoplasms. Identification of genomic alterations in cytological specimens that distinguish between benign and malignant follicular tumors would have great clinical value. This study identified chromosomal imbalances in a set of 126 thyroid frozen follicular lesions characterized by histopathology, using aCGH, FISH, and DNA ploidy determination. An evaluation algorithm was developed based on a panel of three FISH experiments to better distinguish between follicular adenomas and carcinomas of the thyroid. This algorithm detects structural abnormalities that were observed in about half of the follicular thyroid carcinomas. These molecular markers may be therefore useful as an adjunct for making a differential diagnosis of follicular adenoma versus follicular carcinoma using cytological material obtained by FNA. Further information on the values in the comment columns: [FISH_1p_Loss : Status for abnormality found in terms of copy number variation for chr1p by FISH], [FISH_22_Loss : Status for abnormality found in terms of copy number variation for chr22 by FISH], [FISH_X_Gain : Status for abnormality found in terms of copy number variation for chrX by FISH], [FISH_Global : Status for abnormality found in terms of copy number variation for at least one of these (chr1p, chr22, chrX) by FISH], [DNA_Index : Measured by flow cytometry], [KRAS_Mutation : Mutation status for KRAS, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [HRAS_Mutation : Mutation status for HRAS, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [NRAS_Mutation : Mutation status for NRAS, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [BRAF_Mutation : Mutation status for BRAF, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [CTNNB1_Mutation : Mutation status for CTNNB1, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [PIK3CA_Mutation : Mutation status for PIK3CA, obtained from Sanger sequencing. wt for wild-type, mut for mutant], [PAX8-PPARg_Fusion : Status for the PAX8-PPARG gene fusion, obtained from qRT-PCR. pos for presence of fusion, neg for absence], [RET-PTC_Fusion : Status for the RET-PTC gene fusion, obtained from qRT-PCR. pos for presence of fusion, neg for absence], [Mutation_Status : Global mutation status, combining results from HRAS, NRAS mutation status, and PAX8-PPARG fusion status], [Tumor_Size_cm : Tumor size in centimeters], [pT : Classes defined according to the size of the tumors (for more information, check AJCC classification)], [pN : Classes defined according to the number of nodes involved or not (for more information, check AJCC classification)], [pM : Classes defined according to the presence or absence of distant metastases (for more information, check AJCC classification)], [Carcinoma_Histo_Type : Histological type for carcinoma. MIF for minimally invasive, WIF for widely invasive], [Adenoma_Histo_Type : Histological type for adenoma. MIC for microvesicular, MAC for macrovesicular, BOTH for both], [Follow-up_month : Patient follow-up in months], [Alive_status : Patient alive status. yes for alive patient, no for deceased patient], [Metastasis_status : Presence of metastasis during the follow-up. yes for positive, no for negative, possible when uncertainty remains].
Project description:Thyroid cancer is common, yet the sequence of alterations that promote tumor formation are incompletely understood. Here we describe a novel model of thyroid carcinoma in zebrafish that reveals temporal changes due to BRAFV600E. Through the use of real-time in vivo imaging we observe disruption in thyroid follicle structure that occurs early in thyroid development. Combinatorial treatment using BRAF and MEK inhibitors reversed the developmental effects induced by BRAFV600E. Adult zebrafish expressing BRAFV600E in thyrocytes developed invasive carcinoma. We identified a gene expression signature from zebrafish thyroid cancer that is predictive of disease free survival in patients with papillary thyroid cancer. Gene expression studies nominated TWIST2 as a key effector downstream of BRAF. Using CRISPR/Cas9 to genetically inactivate a TWIST2 orthologue, we suppressed the effects of BRAFV600E and restored thyroid morphology and hormone synthesis. These data suggest that expression of TWIST2 plays a role in an early step of BRAFV600E-mediated transformation. Overall design: 3 embryo tg-TOM (tg:TdTomato), 3 embryo tg-BRAFV600E-TOM, 3 adult tg-TOM and 5 adult tg-BRAFV600E-TOM biological replicates were sequenced. Strains with tg:TdTomato express the TdTomato fluorophore under control of the zebrafish thyroglobulin promoter (tg).
Project description:Exposure to ionizing radiation during childhood markedly increases the risk of developing papillary thyroid cancer. We identified non-overlapping somatic driver mutations in all 26 cases of post-Chernobyl thyroid cancers we studied through candidate gene assays and next generation RNA-sequencing. We found that 22/26 harbored fusion oncogenes arising primarily through intrachromosomal rearrangements. Altogether 23/26 of the oncogenic drivers identified in this cohort aberrantly activate MAPK signaling, including the two novel somatic rearrangements ETV6-NTRK3 and AGK-BRAF. Two other tumors harbored distinct fusions leading to overexpression of the nuclear receptor PPARγ. A lower prevalence of fusion oncogenes was found in a cohort of pediatric thyroid cancers from children from the same geographical regions that were not exposed to radiation. Radiation-induced thyroid cancers are a paradigm of tumorigenesis driven by fusion oncogenes that activate MAPK signaling or, less frequently, a PPARγ-driven transcriptional program. Examination of transcriptome profiles and genetic somatic changes in thyroid cancer.
Project description:Genes and pathways that allow cells to cope with oncogene-induced stress represent selective cancer therapeutic targets that remain largely undiscovered. In this study, we identify a RhoJ signaling pathway that is a selective therapeutic target for BRAF mutant cells. RhoJ deletion in BRAF mutant melanocytes modulates the expression of the pro-apoptotic protein BAD as well as genes involved in cellular metabolism, impairing nevus formation, cellular transformation, and metastasis. Short-term treatment of nascent melanoma tumors with PAK inhibitors that block RhoJ signaling halts the growth of BRAF mutant melanoma tumors in vivo and induces apoptosis in melanoma cells in vitro via a BAD-dependent mechanism. As up to 50% of BRAF mutant human melanomas express high levels of RhoJ, these studies nominate the RhoJ-BAD signaling network as a therapeutic vulnerability for fledgling BRAF mutant human tumors. Overall design: 5 Braf CA/+; Pten fl/+; Cre +; RhoJ +/+ melanoma tumors from mice were compared to 5 Braf CA/+; Pten fl/+; Cre +; RhoJ -/- melanoma tumors. Standard RNA isolation progocols were used.
Project description:The first clinical trial testing the combination of targeted therapy with a BRAF inhibitor vemurafenib and immunotherapy with a CTLA-4 antibody ipilimumab was terminated early due to significant liver toxicities, possibly due to paradoxical activation of the MAPK pathway by BRAF inhibitors in tumors with wild type BRAF. MEK inhibitors can potentiate the MAPK inhibition in tumor, while potentially alleviating the unwanted paradoxical MAPK activation. With a mouse model of syngeneic BRAFV600E driven melanoma (SM1), we tested whether the addition of the MEK inhibitor trametinib would enhance the immunosensitization effects of the BRAF inhibitor dabrafenib. Combination of dabrafenib and trametinib with pmel-1 adoptive cell transfer (ACT) showed complete tumor regression. Bioluminescent imaging and tumor infiltrating lymphocyte (TIL) phenotyping showed increased effector infiltration to tumors with dabrafenib, trametinib or dabrafenib plus trametinib with pmel-1 ACT combination. Intracellular IFN gamma staining of the TILs and in vivo cytotoxicity studies showed trametinib was not detrimental to the effector functions in vivo. Dabrafenib increased tumor associated macrophages and T regulatory cells (Tregs) in the tumors, which can be overcome by addition of trametinib. Microarray analysis revealed increased melanoma antigen, MHC expression, and global immune-related gene upregulation with the triple combination therapy. Given the up-regulation of PD-L1 seen with dabrafenib and/or trametinib combined with antigen specific ACT, we tested the triple combination of dabrafenib, trametinib with anti-PD1 therapy, and observed superior anti-tumor effect to SM1 tumors. Our findings support the testing of these combinations in patients with BRAFV600E mutant metastatic melanoma. SM1 tumors were implanted into C57BL/6 mice. Mice were treated by ACT of pmel-1 splenocytes or C57BL/6 splenocytes as control. Pmel-1 treated mice were additionally treated with either vehicle, dabrafenib, trametinib, or combination of both drugs and control mice were treated with vehicle or combination of both drugs.
Project description:Multiple BRAF inhibitor resistance mechanisms have been described, however their relative frequency, clinical correlates, and effect on subsequent therapy have not been assessed in patients with metastatic melanoma. Excised progressing BRAFV600 mutant melanoma metastases (Prog) from patients treated with dabrafenib (n=22) or vemurafenib (n=8) were analyzed for known resistance mechanisms. Oncogenic signaling in Prog and matched pre-treatment tumors was examined using gene expression analysis. Resistance mechanisms were correlated with clinicopathologic features and outcome. A resistance mechanism was identified in 21/38 (55%) Prog samples from 30 patients; BRAF splice variants (n=12, 32%), N-RAS mutations (n=3, 8%), BRAF amplification (n=3, 8%), MEK1/2 mutations (n=3, 8%) and an AKT1 mutation (n=1, 3%). Four Progs tumours displayed multiple resistance mechanisms, and four patients with multiple Progs demonstrated inter-tumoral heterogeneity of resistance mechanisms. Six (21%) of 29 Progs showed loss of MAPK activity by gene expression analysis. These MAPK-inhibited Progs had unknown resistance mechanisms, and these patients had a shorter progression-free survival than patients with MAPK re-activated Progs. There were no responses to subsequent targeted therapy, even when the identified mechanism of resistance was predicted to be responsive. Heterogeneity of resistance mechanisms was common between patients, within patients and within individual tumors. The MAPK pathway remained inhibited in a subset of resistant tumors with unknown mechanisms of resistance, and the outcomes of patients with these tumors are poor. The use of sequential targeted therapies based on the molecular characteristics of a single progressing biopsy is unlikely to provide improved clinical outcomes. Total RNA was obtained from fresh-frozen melanoma tumour samples from patients before commencing treatment with dabrafenib or vemurafenib and at time of tumour progression.