30 mCi exploratory scan for two-step dosimetric 131I therapy in differentiated thyroid cancer patients: A novel approach and case report.

Differentiated thyroid cancer patients with significantly elevated or rapidly rising serum thyroglobulin (Tg) levels and negative diagnostic radioiodine scans (DxScan) often present a therapeutic dilemma in deciding whether or not to administer an 131I treatment. In this report, we describe a novel two-step approach of a 30 mCi 131I exploratory scan before a dosimetric 131I therapy to help "un-blind" the treating physician of the benefit/risk ratio of a further "blind" 131I treatment. A 51-year-old man presented with rising Tg levels, a negative DxScan, and a history of widely metastatic follicular thyroid cancer. He had undergone total thyroidectomy, remnant ablation with 3.8 GBq (103.5 mCi) of 131I, Gammaknife®, and treatment with 12.1 GBq (326 mCi) of 131I for multiple metastases. However, at 19 months after the treatments, his Tg levels continued to rise, and scans demonstrated no evidence of radioiodine-avid metastatic disease. In anticipation of a "blind" 131I treatment, the medical team and the patient opted for a 30 mCi exploratory scan. The total dosimetrically guided prescribed activity (DGPA) was decided based on the whole-body dosimetry. The patient was first given 30 mCi of 131I, and the exploratory scan was performed 22 h later, which demonstrated 131I uptake in the left lung, left humeral head, T10, and right proximal thigh muscle. Based on the positive exploratory scan, the remainder of the DGPA was administered within several hours after the scan. On the post-DGPA treatment scan performed at 5-7 days, the lesions seen on the ~ 22 h exploratory scan were confirmed, and an additional lesion was observed in the left kidney. The 30 mCi exploratory scan suggested the potential for a response in the radioiodine-avid lesions despite a negative diagnostic scan. This method allows 131I treatment to be administered to patients who may have a greater potential for a therapeutic response while avoiding unwarranted side effects in those patients with nonavid disease.

Detection of BRAFV600E in Liquid Biopsy from Patients with Papillary Thyroid Cancer Is Associated with Tumor Aggressiveness and Response to Therapy.

The detection of rare mutational targets in plasma (liquid biopsy) has emerged as a promising tool for the assessment of patients with cancer. We determined the presence of cell-free DNA containing the BRAFV600E mutations (cfBRAFV600E) in plasma samples from 57 patients with papillary thyroid cancer (PTC) with somatic BRAFV600E mutation-positive primary tumors using microfluidic digital PCR, and co-amplification at lower denaturation temperature (COLD) PCR. Mutant cfBRAFV600E alleles were detected in 24/57 (42.1%) of the examined patients. The presence of cfBRAFV600E was significantly associated with tumor size (p = 0.03), multifocal patterns of growth (p = 0.03), the presence of extrathyroidal gross extension (p = 0.02) and the presence of pulmonary micrometastases (p = 0.04). In patients with low-, intermediate- and high-risk PTCs, cfBRAFV600E was detected in 4/19 (21.0%), 8/22 (36.3%) and 12/16 (75.0%) of cases, respectively. Patients with detectable cfBRAFV600E were characterized by a 4.68 times higher likelihood of non-excellent response to therapy, as compared to patients without detectable cfBRAFV600E (OR (odds ratios), 4.68; 95% CI (confidence intervals)) 1.26-17.32; p = 0.02). In summary, the combination of digital polymerase chain reaction (dPCR) with COLD-PCR enables the detection of BRAFV600E in the liquid biopsy from patients with PTCs and could prove useful for the identification of patients with PTC at an increased risk for a structurally or biochemically incomplete or indeterminate response to treatment.

Microfluidic Droplet Digital PCR Is a Powerful Tool for Detection of BRAF and TERT Mutations in Papillary Thyroid Carcinomas.

We examined the utility of microfluidic digital PCR (dPCR) for detection of BRAF and TERT mutations in thyroid tumors. DNA extracted from 100 thyroid tumors (10 follicular adenomas, 10 follicular cancers, 5 medullary cancers, and 75 papillary thyroid cancer (PTC) were used for detection of BRAF and TERT mutations. Digital PCRs were performed using rare mutation SNP genotyping assays on QuantStudio 3D platform. In PTCs, BRAFV600E was detected by dPCR and Sanger sequencing in 42/75 (56%) and in 37/75 (49%), respectively. BRAFV600E was not detected in other tumors. The ratio of mutant/total BRAF alleles varied from 4.7% to 47.5%. These ratios were higher in classical PTCs (27.1%) as compared to follicular variant PTCs (9.4%) p = 0.001. In PTCs with and without metastases, the ratios of mutant/total BRAF alleles were 27.6% and 18.4%, respectively, (p = 0.03). In metastatic lesions percentages of mutant/total BRAF alleles were similar to those detected in primary tumors. TERTC228T and TERTC250T were found in two and one cases, respectively, and these tumors concomitantly harbored BRAFV600E. These tumors exhibited gross extra-thyroidal extension, metastases to lymph nodes, and pulmonary metastases (one case). Our results showed that dPCR allows quantitative assessment of druggable targets in PTCs and could be helpful in a molecular-based stratification of prognosis in patients with thyroid cancer.

Thyroxine-binding globulin deficiency due to a novel SERPINA7 mutation: Clinical characterization, analysis of X-chromosome inactivation pattern and protein structural modeling.

OBJECTIVE: Thyroxine-binding globulin (TBG) is the major human thyroid hormone transport protein, encoded by the SERPINA7 gene (Xq22.2). We aim to investigate the molecular basis of partial TBG deficiency (TBG-PD) in a female, by evaluating the X-chromosome inactivation pattern as well as the mutant protein structural modeling. DESIGN AND METHODS: Sequencing of the coding region of the SERPINA7 gene was performed in a female with a TBG-PD phenotype and her first-degree relatives. The proband presented with low serum levels of total T3 (TT3) and total T4 (TT4), serum TSH level of 5.4 µUI/mL (normal range, 0.35-5.5), and serum TBG level of 5.5 mg/L (normal range, 13.6-27.2). X-chromosome inactivation pattern was evaluated by methylation analysis of the androgen receptor gene (Xq11.2). Structural analysis of the SERPIN family was performed using Pymol and Areaimol, and PFSTATS for conservation analysis and family-wide investigation of equivalent positions in human homologs. Modeller was used for point mutation structural modeling. RESULTS: A novel missense SERPINA7 mutation (p.R35W; c.163C > T) was found in heterozygosity in the proband, and in hemizygosity in her affected siblings. The proband X-chromosome inactivation ratio was 20:80. The substitution of an arginine by a tryptophan is predicted to disrupt the protein surface and main electrostatic interactions. Tryptophans are extremely rare (0.1%) in this position. CONCLUSIONS: We report a new SERPINA7 variant associated with TBG-PD in three siblings. We named this variant TBG-Brasilia. The X-chromosome inactivation pattern may have accounted for the rare phenotypic expression in a female. The hydrophobic nature of the mutant is predicted to create an apolar patch at the surface, which results in protein aggregation and/or misfolding, potentially responsible for thyroid hormone transport defect.