Gross deletion analysis of the HRPT2 gene is indicated for all patients negative for mutation, presenting with HPT-JT or familial isolated hyperparathyroidism, parathyroid carcinoma, or in patients with apparently sporadic parathyroid adenoma diagnosed at a young age, having a severe hypercalcemia.
BackgroundMolecular alterations of the MAPK pathway are frequently observed in papillary thyroid carcinomas (PTCs). It leads to a constitutive activation of the signalling pathway through an increase in MEK and ERK phosphorylation. ERK is negatively feedback-regulated by Dual Specificity Phosphatases (DUSPs), especially two ERK-specific DUSPs, DUSP5 (nuclear) and DUSP6 (cytosolic). These negative MAPK regulators may play a role in thyroid carcinogenesis.MethodsMAPK pathway activation was analyzed in 11 human thyroid cancer cell lines. Both phosphatases were studied in three PCCL3 rat thyroid cell lines that express doxycycline inducible PTC oncogenes (RET/PTC3, H-RASV12 or BRAFV600E). Expression levels of DUSP5 and DUSP6 were quantified in 39 human PTCs. The functional role of DUSP5 and DUSP6 was investigated through their silencing in two human BRAFV600E carcinoma cell lines.ResultsBRAFV600E human thyroid cancer cell lines expressed higher phospho-MEK levels but not higher phospho-ERK levels. DUSP5 and DUSP6 are specifically induced by the MEK-ERK pathway in the three PTC oncogenes inducible thyroid cell lines. This negative feedback loop explains the tight regulation of p-ERK levels. DUSP5 and DUSP6 mRNA are overexpressed in human PTCs, especially in BRAFV600E mutated PTCs. DUSP5 and/or DUSP6 siRNA inactivation did not affect proliferation in two BRAFV600E mutated cell lines, which may be explained by a compensatory increase in other phosphatases. In the light of this, we observed a marked DUSP6 upregulation upon DUSP5 inactivation. Despite this, DUSP5 and DUSP6 positively control cell migration and invasion.ConclusionsOur results are in favor of a stronger activation of the MAPK pathway in BRAFV600E PTCs. DUSP5 and DUSP6 have pro-tumorigenic properties in two BRAFV600E PTC cell line models.
Serum stimulation of mammalian cells induces, via the MAPK pathway, the nuclear protein DUSP5 (dual-specificity phosphatase 5), which specifically interacts with and inactivates the ERK1/2 MAP kinases. However, molecular mechanisms underlying DUSP5 induction are not well known. Here, we found that the DUSP5 mRNA induction depends on a transcriptional regulation by the MAPK pathway, without any modification of the mRNA stability. Two contiguous CArG boxes that bind serum response factor (SRF) were found in a 1 Kb promoter region, as well as several E twenty-six transcription factor family binding sites (EBS). These sites potentially bind Elk-1, a transcription factor activated by ERK1/2. Using wild type or mutated DUSP5 promoter reporters, we demonstrated that SRF plays a crucial role in serum induction of DUSP5 promoter activity, the proximal CArG box being important for SRF binding in vitro and in living cells. Moreover, in vitro and in vivo binding data of Elk-1 to the same promoter region further demonstrate a role for Elk-1 in the transcriptional regulation of DUSP5. SRF and Elk-1 form a ternary complex (Elk-1-SRF-DNA) on DUSP5 promoter, consequently providing a link to an important negative feedback tightly regulating phosphorylated ERK levels.
Most combined oral contraceptive pills contain ethinyl estradiol (EE) with progestins. In order to minimize the pill's cardiovascular risks, the concept of using 17β-estradiol (E2), the endogenous estradiol, arose in the 1970s. Many attempts to develop a pill containing 17β-E2 have failed as cycle control was low. The first pill containing 17β-E2 was launched in 2011. This monophasic pill contains 24 pills with 1.5 mg 17β-E2 and 2.5 mg nomegestrol acetate, and four placebo pills. Studies conducted in Europe and the USA demonstrate that its Pearl index is 0.38 and 1.13, respectively. It has less influence on hemostasis, fibrinolysis markers, lipids and carbohydrate metabolism than the combined oral contraceptive levonorgestrel/EE (150 g/30 g and 100 µg/20 µg). Withdrawal bleedings are shorter and lighter as compared with women using drospirenone/EE (3 mg/ 30 µg). The number of women without withdrawal bleeding is approximately 30% after 12 months. Even though its contraindications are identical to other combined oral contraceptives, this nomegestrol acetate/E2 pill should be considered to be of interest for many women.
Three years and eight months after vandetanib initiation, there was no sign of recurrence of hypercortisolism. This case illustrates the long-term effectiveness of vandetanib in maintaining the control of hypercortisolism in MTC-related CS.
Background
Primary hyperparathyroidism (HPT1) is the most frequent endocrinopathy in multiple endocrine neoplasia type 1 (MEN1). Its surgical management is challenging. We aimed to describe and compare the imaging findings of parathyroid ultrasound (US), sestaMIBI scintigraphy (sestaMIBI), and 18F‐fluorocholine (FCH) PET/CT in a series of MEN1 patients with HPT1.
Methods
Retrospective analysis of a cohort of MEN1 patients with HPT1 assessed by parathyroid US, sestaMIBI scintigraphy and SPECT/CT, and FCH‐PET/CT for potential surgery between 2015 and 2019.
Results
Twenty‐two patients with a confirmed diagnosis of MEN1 who presented with HPT1 and were assessed by the 3 imaging modalities were included. After imaging workups, 11 patients were operated on for the first time, 4 underwent a redo surgery, and 7 did not undergo an operation. The overall patient‐based positivity rate of imaging was 91% (20 of 22) for parathyroid US and 96% (21 of 22) for both sestaMIBI and FCH‐PET/CT. The 3 imaging modalities demonstrated negative findings in 1/22 patient who did not undergo surgery. Overall, 3 pathologic glands were not detected by any imaging technique. SestaMIBI and FCH‐PET/CT both resulted in the same 3 false‐positive results in ectopic areas with a significant uptake on two thymic carcinoid tumors and one inflammatory lymph node. FCH‐PET/CT provided more surgically relevant data than sestaMIBI in 4/11 patients with initial surgery and in 1/4 patient who underwent redo surgery.
Conclusions
Compared to sestaMIBI scintigraphy, FCH‐PET/CT provides additional information regarding the number of pathologic parathyroid glands and their localization in MEN1 patients with HPT1.
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