Comprehensive Genomic Profiling Alters Clinical Diagnoses in a Significant Fraction of Tumors Suspicious of Sarcoma

PURPOSE

Tumor classification is a key component in personalized cancer care. For soft tissue and bone tumors, this classification is currently based primarily on morphology assessment and immunohistochemical staining. However, these standard-of-care methods can pose challenges for pathologists. We therefore assessed how whole-genome and whole-transcriptome sequencing (WGTS) impacted tumor classification and clinical management when interpreted together with histomorphology.

EXPERIMENTAL DESIGN

We prospectively evaluated WGTS in routine diagnostics of 200 soft tissue and bone tumors suspicious for malignancy, including DNA and RNA isolation from the tumor, and DNA isolation from a peripheral blood sample or any non-tumor tissue.

RESULTS

Based on specific genomic alterations or absence of presumed findings, WGTS resulted in reclassification of 7% (13/197) of the histopathological diagnoses. Four cases were downgraded from low-grade sarcomas to benign lesions, and two cases were reclassified as metastatic malignant melanomas. Fusion genes associated with specific tumor entities were found in 30 samples. For malignant soft tissue and bone tumors, we identified treatment relevant variants in 15% of cases. Germline pathogenic variants associated to a hereditary cancer syndrome were found in 22 participants (11%).

CONCLUSION

We conclude that WGTS provides an important dimension of data which aids in the classification of soft tissue and bone tumors, correcting a significant fraction of clinical diagnoses, and identifies molecular targets relevant for precision medicine. However, genetic findings need to be evaluated in their morphopathological context, just as germline findings need to be evaluated in the context of patient phenotype and family history.

Surgical outcome after thyroidectomy due to Graves' disease and Lugol iodine treatment: a retrospective register-based cohort study

PURPOSE

This study aimed to investigate the relationship between Lugol iodine treatment in a rescue setting and surgical outcomes in Graves' disease patients.

METHODS

The retrospective register-based cohort study included 813 patients who had undergone primary total thyroidectomy with a primary diagnosis of Graves' disease (ICD-code E05.0) at Karolinska University Hospital in Stockholm, Sweden, between January 2008 and December 2015. Of 813 patients, 33 (4.1%) were given Lugol iodine before surgery and the remaining, the non-Lugol group, did not. The study's primary outcomes were post-operative calcium treatment day 1, calcium and vitamin D supplements at discharge and follow-up. Secondary outcomes were laryngeal nerve damage and bleeding (defined as re-operation).

RESULTS

Differences were found between the Lugol and non-Lugol groups in the treatment of calcium day 1 (45.5% vs 26.7%, p = 0.018), at discharge (36.4% vs. 16.2%, p = 0.002) and vitamin D supplements at discharge (36.4% vs. 19.1%, p = 0.015) as surrogate variables for hypocalcemia post-operatively. No differences could be seen at 4-6 weeks and six-months follow-up. There were no differences between the Lugol and non-Lugol groups in terms of operation time, laryngeal nerve damage, and bleeding.

CONCLUSION

Patients in our cohort undergoing thyroidectomy due to Graves' disease pre-operatively treated with Lugol iodine as a rescue therapy had a higher risk of experiencing short term post-operative hypocalcemia.

Surgical strategy in lithium-associated hyperparathyroidism: A population-based study

BACKGROUND

The extent of parathyroidectomy (PTX) recommendation in patients with lithium-associated hyperparathyroidism (LAH) remains controversial. The primary objectives of this study were to analyze extent of surgery, complications, and long-term outcomes.

METHODS

A population-based study, including all primary hyperparathyroidism (PHPT) patients who underwent PTX in Sweden between 2008 and 2017. Data on exhibited lithium prescriptions, morbidity, surgical approach, and outcomes were collected from relevant national registers and the Scandinavian Quality Register of Thyroid, Parathyroid, and Adrenal Surgery. Patients with lithium exposure before PTX were defined as having LAH. Descriptive summary statistics and regression models were used to evaluate differences in comorbidities, surgical approach, and outcomes between LAH and PHPT not exposed to lithium (non-LAH).

RESULTS

Lithium exposure was significantly more common among PHPT (n = 202, 2.3%) than in controls (n = 416, 0.5%); OR 5.0 (95% CI 4.2-5.9). The risk of LAH correlated to the length of lithium exposure. In the LAH-group, the surgical procedures were more extensive and associated with a higher risk of postoperative bleeding, wound infections, persistent hypercalcemia, and hypocalcemia that remained after adjustment for the higher percentage of multiglandular disease. However, the cumulative risk of re-admission for PHPT was similar the first years after PTX and primarily elevated for patients with >5 years duration of lithium exposure prior to surgery.

CONCLUSIONS

The findings support the perception of LAH as a complex entity. We recommend a functionally oriented approach, aimed to obtain and maintain normocalcemia for as long as possible, minimizing the risk of permanent hypoparathyroidism, and accepting some risk of recurrence.

Regional variations in the management of primary hyperparathyroidism in Sweden: population-based case-control study

BACKGROUND

Substantial disparities in the utilization of parathyroidectomy for primary hyperparathyroidism have been reported. This study aimed to analyse regional variations in parathyroidectomy incidence with respect to the patient's disease burden and socioeconomic status.

METHODS

A population-based case-control study included all patients with primary hyperparathyroidism who underwent parathyroidectomy in Sweden between 2008 and 2017 and 10 matched controls. Data on demographic and socioeconomic variables, co-morbidities and drug prescriptions were collected from relevant national registers. Conditional logistic regression was used to analyse predictors of parathyroidectomy.

RESULTS

A total of 8626 patients with primary hyperparathyroidism (77% women) underwent parathyroidectomy during the study interval. The annual incidence of parathyroidectomy was 9.0 per 100 000 persons. The annual age-adjusted regional incidences of parathyroidectomy varied between 3.3 and 16.9 operations per 100 000 inhabitants. Except for a small underrepresentation of patients with lower education, no effect of socioeconomic variables was observed. Compared with matched controls, the parathyroidectomy group had increased odds ratios of having developed classical symptoms of primary hyperparathyroidism and being prescribed medication against cardiovascular disorders and psychiatric illness at the time of parathyroidectomy. Increased risks of kidney stones and osteoporosis were observed 5 years before parathyroidectomy. Patients with primary hyperparathyroidism selected for parathyroidectomy from regions with a low incidence of operations had a higher prevalence of kidney stones, osteoporosis and hypertension, as well as larger adenomas and higher calcium levels at the time of parathyroidectomy compared with patients in high-incidence regions.

CONCLUSION

The considerable variation in parathyroidectomy seems more likely associated with different clinical thresholds for detection of primary hyperparathyroidism and referral to surgery than socioeconomic disparities.

Transplantation and Noninvasive Longitudinal In Vivo Imaging of Parathyroid Cells: A Proof-of-Concept Study

The parathyroid cell is a vital regulator of extracellular calcium levels, operating through the secretion of parathyroid hormone (PTH). Despite its importance, the regulation of PTH secretion remains complex and not fully understood, representing a unique interplay between extracellular and intracellular calcium, and hormone secretion. One significant challenge in parathyroid research has been the difficulty in maintaining cells ex vivo for in-depth cellular investigations. To address this issue, we introduce a novel platform for parathyroid cell transplantation and noninvasive in vivo imaging using the anterior chamber of the eye as a transplantation site. We found that parathyroid adenoma tissue transplanted into the mouse eye engrafted onto the iris, became vascularized, and retained cellular composition. Transplanted animals exhibited elevated PTH levels, indicating a functional graft. With in vivo confocal microscopy, we were able to repetitively monitor parathyroid graft morphology and vascularization. In summary, there is a pressing need for new methods to study complex cellular processes in parathyroid cells. Our study provides a novel approach for noninvasive in vivo investigations that can be applied to understand parathyroid physiology and pathology under physiological and pathological conditions. This innovative strategy can deepen our knowledge on parathyroid function and disease.

Ca2+-activated K+ channels modulate membrane potential in the human parathyroid cell: Possible role in exocytosis

The relationships between parathyroid hormone (PTH) secretion and parathyroid cell membrane potential, including the identities and roles of K+ channels that regulate and/or modulate membrane potential are not well defined. Here we have used Western blot/immunohistochemistry as well as patch-clamp and perifusion techniques to identify and localize specific K+ channels in parathyroid cells and to investigate their roles in the control of membrane potential and PTH secretion. We also re-investigated the relationship between membrane potential and exocytosis. We showed that in single human parathyroid cells K+ current is dependent on at least two types of Ca2+-activated K+ channels: a small-conductance Ca2+-activated K+ channel (KSK) and a large-conductance voltage and Ca2+-activated K+ channel (KBK). These channels were sensitive to specific peptide blocking toxins including apamin, charybdotoxin, and iberiotoxin. These channels confer sensitivity of the membrane potential in single cells to high extracellular K+, TEA, and peptide toxins. Blocking of KBK potently inhibited K+ channel current, and KBK was shown to be expressed in the plasma membrane of parathyroid cells. In addition, when using the capacitance technique as an indicator of exocytosis, clamping the parathyroid cell at -60 mV prevented exocytosis, whereas holding the membrane potential at 0 mV facilitated it. Taken together, the results show that human parathyroid cells have functional KBK and KSK channels but the data presented herein suggest that KBK/KSK channels likely contribute to the maintenance of the membrane potential, and that membrane potential, per se, modulates exocytosis independently of [Ca2+]i.

Kept in the Closet: Structural Stigma and the Timing of Sexual Minority Developmental Milestones Across 28 European Countries

Structural stigma's role in lesbian, gay, and bisexual (LGB) people's attainment of identity development milestones remains unknown. In a sample of 111,498 LGB people (ages 15 to 65+) living across 28 European countries, associations were investigated between structural stigma measured using an objective index of discriminatory country-level laws and policies affecting LGB people and the timing and pacing of LGB self-awareness, coming out, and closet duration, and subgroup differences in these associations. On average, self-awareness occurred at age 14.8 years old (SD = 5.1), coming out occurred at 18.5 years old (SD = 5.7), and the closet was 3.9 years long (SD = 4.9); thereby highlighting adolescence as a key period for sexual identity development and disclosure. Greater structural stigma was associated with higher odds of never coming out, later age of coming out, and longer closet duration. Gender identity, transgender identity, and sexual identity moderated associations between structural stigma and these developmental milestones. Reducing structural stigma can plausibly promote sexual identity development among LGB populations, especially during adolescence when identity related milestones are often attained.

Altered expression of the IGF2‑H19 locus and mitochondrial respiratory complexes in adrenocortical carcinoma

Abnormalities of the insulin-like growth factor 2 (IGF2)-H19 locus with the overexpression of IGF2 are frequent findings in adrenocortical carcinoma (ACC). The present study assessed the expression of RNAs and microRNAs (miRNAs/miRs) from the IGF2-H19 locus using PCR-based methods in ACC and adrenocortical adenoma (ACA). The results were associated with proteomics data. IGF2 was overexpressed in ACC, and its expression correlated with that of miR-483-3p and miR-483-5p hosted by IGF2. The downregulated expression of H19 in ACC compared to ACA correlated with miR-675 expression hosted by H19. Several proteins exhibited an inverse correlation in expression and were predicted as targets of miR-483-3p, miR-483-5p or miR-675. Subsets of these proteins were differentially expressed between ACC and ACA. These included several proteins involved in mitochondrial metabolism. Among the mitochondrial respiratory complexes, complex I and IV were significantly decreased in ACC compared to ACA. The protein expression of NADH:ubiquinone oxidoreductase subunit C1 (NDUFC1), a subunit of mitochondrial respiratory complex I, was further validated as being lower in ACC compared to ACA and normal adrenals. The silencing of miR-483-5p increased NDUFC1 protein expression and reduced both oxygen consumption and glycolysis rates. On the whole, the findings of the present study reveal the dysregulation of the IGF2-H19 locus and mitochondrial respiration in ACC. These findings may provide a basis for the further understanding of the pathogenesis of ACC and may have potential values for diagnostics and treatment.

Structural stigma and 7-year improvement in life satisfaction: A repeated cross-sectional study of sexual minority individuals across 28 countries

Background

Structural stigma toward sexual minority individuals varies widely across countries and is associated with psychosocial health outcomes. Yet, the association of changes in country-level structural stigma over time, as has recently characterized many European countries, with such outcomes is largely unknown. The current study examined the association between change in structural stigma from 2012 to 2019 across European Union countries and change in life satisfaction among sexual minority individuals during the same period. Secondary analyses examined whether changes in structural stigma differentially benefitted some subgroups of sexual minority individuals more than others.

Methods

The current study analyzed data from sexual minority respondents (2012: n = 82,668; 2019: n = 96,576) living in 28 European countries.

Results

Adjusted multilevel models showed that life satisfaction had improved among sexual minority individuals in all countries between 2012 and 2019 (β = 0.32, 95% CI: 0.29, 0.35), but the improvement was stronger among those living in higher stigma countries compared to those living in lower stigma countries. Changes also varied by relationship status; the strongest improvement in life satisfaction as a function of improvement in structural stigma was found among sexual minority individuals in a relationship.

Conclusions

Although life satisfaction has increased during the past decade among sexual minority individuals living in Europe, significant variation in this change exists across countries as a function of country-level structural stigma and individual sociodemographic characteristics. The findings support the relevance of structural stigma for sexual minority individuals’ life satisfaction and call for further research to understand the differential impact of structural stigma across sexual minority subgroups.

Structural stigma and sexual minority men’s depression and suicidality: A multi-level examination of mechanisms and mobility across 48 countries

Background

Sexual minority men are at greater risk of depression and suicidality than heterosexuals. Stigma, the most frequently hypothesized risk factor for this disparity, operates across socioecological levels-structural (e.g., laws), interpersonal (e.g., discrimination), and individual (e.g., self-stigma). However, there is limited data on whether changes in structural stigma, such as when a stigmatized person moves to a lower stigma context, affect mental health, and on the mechanisms underlying this association

Methods

The current study uses data from the 2017/18 European Men-who-have-sex-with-men Internet Survey (n = 123,428), which assessed mental health and psychosocial mediators. We linked these data to an objective indicator of structural stigma related to sexual orientation in respondents’ countries of origin (N = 178) and receiving (N = 48) countries

Results

Among respondents who moved from higher-to-lower structural stigma countries (n = 11,831), longer exposure to the lower structural stigma environments of their receiving countries was associated with a significantly: 1) lower risk of depression and suicidality; 2) lower odds of concealment, internalized homonegativity, and social isolation; and 3) smaller indirect effect of structural stigma on mental health through these mediators.

Conclusions

This study provides evidence that structural stigma is associated with the mental health of sexual minority men, both through proximal experiences and as a function of length of exposure to structurally diverse contexts, at least for those who move higher-to-lower structural stigma contexts. Findings suggest the importance of routinely assessing life-course structural influences on mental health and deploying interventions to address those influences.

Inward and outward currents of native and cloned K(ATP) channels (Kir6.2/SUR1) share single-channel kinetic properties

Background

Methods

Results

Conclusions

•

Outward K(ATP) channel currents are not grouped in bursts regardless of membrane potential.

•

No differences in the number of kinetic states could be seen for single channels between native K(ATP) channels, Kir6.2ΔC26 alone and co-expressed with SUR1 for outward currents.

•

K(ATP) channel open time for outward currents corresponds to burst duration for inward currents.

The role of neoadjuvant imatinib in gastrointestinal stromal tumor (GIST) patients - 20 years of experience from a tertial referral center

Surgery is the cornerstone of gastrointestinal stromal tumor (GIST) treatment, and adjuvant therapy with imatinib has improved survival for high‐risk tumors. The use of imatinib preoperatively has been increasing, but efficacy and impact on patient outcomes have not been formally investigated. This is a retrospective study from a single‐center cohort of patients diagnosed with GIST and treated with neoadjuvant imatinib at Karolinska University Hospital in Stockholm, Sweden over a 20‐year period. Eighty‐four patients diagnosed with GIST and treated with neoadjuvant imatinib were identified and included. Tumors were located throughout the whole gastrointestinal tract but most frequently in the stomach (n = 29; 35%) and the small intestine (n = 30; 36%), followed by the rectum (n = 12; 14%) and the gastroesophageal junction (n = 10; 12%). The tumors were large (mean 10.5 cm) and decreased after treatment (mean 7.6 cm). Main indications for neoadjuvant imatinib were tumor size or anatomical location. None of the patients with stomach tumors and four patients with tumors near the gastroesophageal junction underwent gastrectomy. Three patients with tumors in the small intestine underwent pancreaticoduodenectomy, whereas seven patients with rectal tumors underwent rectal amputation. After surgery, 94% (n = 79) of the tumors had R0‐resection. About one‐fourth experienced local relapse or distant metastasis. In conclusion, neoadjuvant imatinib can reduce tumor size and prevent high morbidity due to more extensive surgery, or at least reduce the extent of the surgery, especially for tumors in the stomach or small intestine.

Seasonal variation in calcium treatment after thyroidectomy as surrogate for post-operative hypocalcemia: a retrospective register-based national cohort study

Background

Hypocalcemia is one of the most common complications of thyroidectomy, and vitamin D deficiency has been found to be an independent risk factor. Sweden is located north of the 55th latitude, resulting in a significant seasonal variation in sun exposure, thereby large variation in the naturally occurring levels of vitamin D. This study aimed to determine if there is a correlation between season of surgery and post-thyroidectomy hypocalcemia.

Methods

We conducted a retrospective register-based observation study on patients who had undergone total thyroidectomy during 2008–2015. In total, 7125 patients operated in Swedish facilities were identified via the Scandinavian Quality Register for Thyroid, Parathyroid, and Adrenal Surgery (SQRTPA). Patients operated during February–April were included in the dark group and patients operated during August–October were included in the bright group. Further stratification was made on the indication for surgery. The primary outcome was post-operative calcium treatment due to hypocalcemia, defined as having received calcium orally or intravenously before discharge.

Results

The risk of receiving post-operative calcium treatment was significantly lower in the bright group (29.7%) compared to the dark group (35.1%), with a relative risk of 0.846 (P < 0.001). This correlation held true if the indication for surgery was goiter or thyrotoxicosis. For malignancy, there was no significant difference between the groups.

Conclusion

In this cohort, total thyroidectomy performed during August–October was associated with a lower rate of calcium treatment given post-operatively when compared to total thyroidectomy performed during February–April. This would indicate a decreased risk of post-operative hypocalcemia if surgery was carried out after the brighter season.

Neuropsychiatric Comorbidity in Primary Hyperparathyroidism Before and After Parathyroidectomy: A Population Study

Background

Primary hyperparathyroidism (PHPT) is often accompanied by neuropsychiatric symptoms. This study aimed to map out psychiatric comorbidity as reflected by medical treatment for psychiatric symptoms.

Methods

A retrospective case–control analysis and a prospective cohort analysis of psychotropic drug utilization before and after PTX. A total of 8279 PHPT patients treated with parathyroidectomy in Sweden between July 1, 2008 and December 31, 2017 compared to a matched control cohort from the total population (n = 82,790). Information on filled prescriptions was collected from the Swedish Prescribed Drug Register (SDR). Socioeconomic data and diagnoses were added by linkage to national patient and population registers. Regression analyses were used to calculate relative drug utilization (OR) within 3 years prior to PTX and relative incidence of drug treatment (RR) within 3 years postoperatively.

Results

Utilization of antidepressant, anxiolytic and sleep medication was more comprehensive in PHPT patients compared with the controls prior to PTX. The most common were benzodiazepines [OR 1.40 (95% CI: 1.31–1.50)] and selective serotonin reuptake inhibitors [SSRI; OR 1.38 (95% CI: 1.30–1.47)]. Postoperatively, the excess prescription rate for anxiolytic benzodiazepines decreased within three years from a 30 to 19% excess and for benzodiazepines for sleep from 31 to 14%. No corresponding decrease in excess prescription rate was observed for SSRI.

Conclusion

PHPT is associated with increased utilization of antidepressive medications and benzodiazepines before PTX. This study implies that psychiatric symptoms should be considered in PHPT patients and continuous medication should be reevaluated after PTX.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00268-022-06485-1.

Imatinib Regulates miR-483-3p and Mitochondrial Respiratory Complexes in Gastrointestinal Stromal Tumors

Metabolic adaptation to increased oxidative phosphorylation (OXPHOS) has been found in gastrointestinal stromal tumor (GIST) upon imatinib treatment. However, the underlying mechanism of imatinib-induced OXPHOS is unknown. Discovering molecules that mediate imatinib-induced OXPHOS may lead to the development of therapeutic strategies synergizing the efficacy of imatinib. In this study, we explored the role of microRNAs in regulating OXPHOS in GIST upon imatinib treatment. Using a microarray approach, we found that miR-483-3p was one of the most downregulated miRNAs in imatinib-treated tumors compared to untreated tumors. Using an extended series of GIST samples, we further validated the downregulation of miR-483-3p in imatinib-treated GIST samples by RT-qPCR. Using both gain- and loss-of-function experiments, we showed that miR-483-3p could regulate mitochondrial respiratory Complex II expression, suggesting its role in OXPHOS regulation. Functionally, miR-483-3p overexpression could rescue imatinib-induced cell death. These findings provide the molecular link for imatinib-induced OXPHOS expression and the biological role of miR-483-3p in regulating cell viability upon imatinib treatment.

Characteristics, Treatment, Outcomes, and Survival in Neuroendocrine G1 and G2 Pancreatic Tumors: Experiences From a Single Tertiary Referral Center

Purpose

Neuroendocrine tumors of the pancreas (Pan-NETs) are usually hormonally inactive with a capacity to metastasize. Since Pan-NETs are rare, more knowledge is needed.

Methods

We reviewed all patients' medical files with Pan-NET treated at a tertiary center (2006-2019). Grade 1 (G1) and grade 2 (G2) tumors were compared. The latter group was subdivided arbitrarily based on proliferation index into G2a (3-9.9%) and G2b (10-19.9%).

Results

We found 137 patients (76 females, 61 males; G1 n=66, G2 n=42), the median age at diagnosis 61 years (interquartile range (IQR) 50-71), and tumor size 2 cm (1.3-5 cm). The initial surgery was performed in 101 patients. The remaining (n=36) were followed conservatively. Metastatic disease was evident in 22 patients (16%) at diagnosis while new lesions developed in 13 out of 22 patients (59%). In patients without previous metastatic disease, progressive disease was discovered in 29% of G1 vs. 55% of G2 patients (P=0.009), 47% of G2a vs. 75% of G2b patients (NS). Survival was poorer in patients with metastasis at diagnosis vs. those with local disease (P<0.001). During follow-up of 74 months, Pan-NET related death was found in 10 patients. Survival was not different between G1 vs. G2 or G2a vs. G2b, or if tumors were functional. Size ≤2 cm was associated with a better outcome (P=0.004). During the follow-up of small tumors (≤2 cm, n=36) two were resected.

Conclusion

In small non-functional Pan-NETs, active surveillance is reasonable. Progressive disease was more common in G2, but survival was similar in G1, G2 and between G2 subgroups. Survival was poorer in patients with metastasis at diagnosis.

Direct interaction of the ATP-sensitive K+ channel by the tyrosine kinase inhibitors imatinib, sunitinib and nilotinib

The ATP-regulated K⁺ channel (K_ATP) plays an essential role in the control of many physiological processes, and contains a ATP-binding site. Tyrosine kinase inhibitors (TKI) are commonly used drugs, that primarily target ATP-binding sites in tyrosine kinases. Herein, we used the patch-clamp technique to examine the effects of three clinically established TKIs on K_ATP channel activity in isolated membrane patches, using a pancreatic β-cell line as a K_ATP channel source. In excised inside-out patches, the activity of the K_ATP channel was dose-dependently inhibited by imatinib with half-maximal concentration of approximately 9.4 μM. The blocking effect of imatinib was slow and reversible. No effect of imatinib was observed on either the large (K_BK) or the small (K_SK) conductance, Ca²⁺-regulated K⁺ channel. In the presence of ATP/ADP (ratio 1) addition of imatinib increased channel activity approximately 1.5-fold. Sunitinib and nilotinib were also found to decrease K_ATP channel activity. These findings are compatible with the view that TKIs, designed to interact at the ATP-binding pocket on the tyrosine receptor, also interact at the ATP-binding site on the K_ATP channel. Possibly, this might explain some of the side effects seen with TKIs.

Prediction of cognitive response to surgery in elderly patients with primary hyperparathyroidism

Background

Primary hyperparathyroidism (pHPT) can be associated with potentially reversible cognitive impairment, which is occasionally mistaken for natural ageing and dementia. The aim was to evaluate short-term medical normalization of hypercalcaemia in surgical decision-making for elderly patients with mild cognitive deficiency.

Methods

Patients with pHPT were included in a prospective observational study. A test panel including the Montreal Cognitive Assessment (MoCA) and validated tools for estimation of psychological status (Hospital Anxiety and Depression Scale, HADS), and muscle strength (timed-stands test, TST) was applied at baseline, after 4 weeks of calcimimetic treatment, and after parathyroidectomy. Mild cognitive impairment was defined by a MoCA score below 26. A longitudinal increase in MoCA score of at least 2 points 6 months after surgery was considered clinically meaningful.

Results

Of 110 patients who underwent testing, 35 aged 50 years or more were identified to have mild cognitive dysfunction, including 19 who were aged at least 70 years (median MoCA score 23, i.q.r. 21–24). Calcimimetic treatment resulted in normalization of calcium levels, and improvements in MoCA and HADS scores, and TST time. Normal MoCA scores (at least 26) were reached in 17 patients by 6 months after surgery, of whom 10 were aged 70 years or older. Long-term increase in MoCA score correlated with the decrease in ionized calcium concentration (r = –0.536, P = 0.022). Baseline calcium concentration and improvement in MoCA with calcimimetic treatment were identified as independent predictors of favourable outcome after parathyroidectomy.

Conclusion

Medical normalization of hypercalcaemia can aid in predicting outcome after parathyroidectomy.

Lifecourse-varying exposure to structural stigma, minority stress reactions, and mental health among sexual minority male migrants

Background

Increasing evidence suggests that structural stigma (e.g., discriminatory laws, policies, and population attitudes) can give rise to minority stress reactions (i.e., rejection sensitivity, internalized homophobia, and identity concealment) to compromise sexual minorities' mental health. Yet, many sexual minorities encounter divergent structural-stigma contexts over the life course, with potentially important implications for their experience of minority stress reactions and mental health. We take advantage of sexual minority male migrants' lifecourse-varying exposures to structural stigma contexts to examine this possibility.

Methods

A sample of 247 sexual minority men who had migrated from 71 countries to the low-structural-stigma context of Sweden completed a survey regarding migration experiences, minority stress reactions, and mental health. This survey was linked to objective indices of structural stigma present in these men's countries of origin, diverse in terms of structural stigma.

Results

Country-of-origin structural stigma was significantly associated with poor mental health and this association was mediated by rejection sensitivity and internalized homophobia, but only among those who arrived to Sweden at an older age and more recently.

Conclusions

Prolonged exposure to high levels of structural stigma can give rise to stressful cognitive, affective, and behavioral patterns to jeopardize sexual minority men's mental health; yet, these consequences of structural stigma may wane with increased duration of exposure to more supportive structural contexts.

Sarcoma of the breast: breast cancer history as etiologic and prognostic factor-A population-based case-control study

Purpose

Sarcomas of the breast account for about 1% of all breast malignancies. The aim of this national survey was to explore etiologic and prognostic factors.

Methods

Utilizing national Swedish registers, all patients registered with mesenchymal tumors in the breast during the period 1993–2013 (n = 344) were identified and compared to up to ten age and gender matched controls. Cancer history was retrieved for cases and controls. Conditional Poisson regression models were used for calculation of odds ratios.

Results

Previous breast cancer was overrepresented among patients with angiosarcoma. The highest risk occurred ≥ 5 years after treatment for breast cancer (OR 73.9, 95% confidence interval, CI, 25.4–215; P < 0.001). An increase in incidence of angiosarcoma was observed during the study period (1.10, 95% CI 1.05–1.16; P < 0.001). The overall incidence of breast sarcoma increased from 1.52 to 2.04 cases per million per year. Angiosarcoma of the breast was associated with a significant excess mortality compared to age-matched controls (HR 4.65, 95% CI 3.01–7.19; P < 0.001).

Conclusions

Angiosarcoma increased in incidence and displayed a more severe clinical course, with significantly shorter survival. The strong association between a history of breast cancer 5 years or more prior to the diagnosis of angiosarcoma points to radiotherapy as a contributing factor.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05802-3) contains supplementary material, which is available to authorized users.

A Single Parathyroid Hormone Measurement Two Hours after a Thyroidectomy Reliably Predicts Permanent Hypoparathyroidism

INTRODUCTION

Hypoparathyroidism is the most common complication following thyroidectomy, and various algorithms for early detection have been suggested. The aim of this study was to evaluate the predictive value of measuring the parathyroid hormone level 2 h after thyroidectomy and whether determination of the perioperative decline in parathyroid hormone added diagnostic value.

METHODS

Patients subjected to thyroidectomy for benign thyroid disorders were analyzed in (1) a retrospective register-based study (366 consecutive patients treated during 2015-2016) and (2) a prospective observational study (39 patients treated during 2018). Optimal cut-off values for postoperative parathyroid hormone and perioperative decline (%) in parathyroid hormone were determined by receiver operating characteristics and area under the curve. Sensitivity, specificity, positive and negative predictive values were calculated using cross tabulation.

RESULTS

The prevalence of hypoparathyroidism the first day after thyroidectomy was higher among patients treated for hyperthyroidism (30% vs 20%; P = 0.03). The optimal cut-off level for postoperative parathyroid hormone was 1.1 pmol/L (area under the curve = 0.887, 95% confidence interval: 0.839-0.934; positive predictive value: 88%, negative predictive value: 93%) for the entire cohort. When the groups were analyzed separately, the optimal cut-off was 1.05 for the non-hyperfunctioning group and 1.55 pmol/L for the group with hyperthyroidism. Twelve months after thyroidectomy, 3% were defined as having permanent hypoparathyroidism. Measurement of parathyroid hormone decline added diagnostic value for one patient with preoperative parathyroid-hormone-elevation associated with vitamin D deficiency.

CONCLUSION

For patients with vitamin D sufficiency, the diagnostic accuracy of a single measurement of parathyroid hormone 2 h after thyroidectomy is an excellent indicator for predicting transient hypoparathyroidism.

Metastatic Anaplastic Thyroid Carcinoma in Complete Remission: Morphological, Molecular, and Clinical Work-Up of a Rare Case

Anaplastic thyroid carcinoma (ATC) exhibits an exceedingly poor prognosis, and the current treatment options are, for most cases, palliative by nature. Few reports of long-time survivors exist, although in these patients, tumors often were limited to the thyroid and/or regional lymph nodes. We describe a 64-year-old male who developed a rapidly growing mass in the left thyroid lobe. A fine-needle aspiration biopsy (FNAB) was consistent with ATC, and the patient underwent preoperative combined chemo- and radiotherapy followed by a hemithyroidectomy. The ensuing histopathological investigation was consistent with ATC adjoined by an oxyphilic well-differentiated lesion, likely a Hürthle cell carcinoma. Tumor margins were negative, and no extrathyroidal extension was noted. Focused next-generation sequencing analysis of the primary tumor tissue identified a TP53 gene mutation but could not identify any potential druggable targets. Additional Sanger sequencing detected a C228T TERT promoter mutation. The tumor was found to be microsatellite stable and displayed PDL1 expression in 80% of tumor cells. Following a CT scan 1 month postoperatively, metastatic deposits were suspected in the lung as well as in the left adrenal gland, of which FNAB verified the latter. Remarkably, upon radiological follow-up, the disease had gone into apparent complete remission. The patient is alive and well with no signs of residual disease after 12 months of follow-up. We here summarize the clinical, histological, and molecular data of this highly interesting patient case and review the literature for possible common denominators with other patients with disseminated ATC.

Untethered lives: Barriers to societal integration as predictors of the sexual orientation disparity in suicidality

Background

Despite increasing legal protections and supportive attitudes toward sexual minorities (e.g., those who identify as lesbian, gay, and bisexual [LGB]) in recent decades, suicidality remains more common among this population than among heterosexuals. While barriers to societal integration have been widely theorized as determinants of suicidality for the general population, they have not been comprehensively explored to explain the sexual orientation disparity in suicidality and/or compared to more established contributors.

Methods

Data come from the cross-sectional Swedish National Public Health Survey, which randomly collected data from individuals (16-84 years of age) annually from 2010 to 2015 (1,281 (2.2%) self-identified as LGB). Analyses examined sexual orientation differences in suicidality (i.e., past-12-month ideation and attempts), and explored the role of barriers to societal integration (i.e., not living with a partner or children, unemployment, and lack of societal trust) in explaining this disparity over-and-above more commonly explored psychological (e.g., depression, substance use) and interpersonal (e.g., discrimination, victimization, lack of social support) suicidality risk factors.

Results

Compared to heterosexuals, suicidal ideation and attempts were more common among both gay men/lesbians (AORideation: 2.51; AORattempts: 4.66), and bisexuals (AORideation: 3.76; AORattempts: 6.06). Barriers to societal integration mediated the association between sexual orientation and suicidality even in models adjusting for established risk factors for suicidality.

Conclusions

The disproportionate barriers to societal integration that LGB individuals experience seem important contributors to the elevated risk of suicidality among sexual minorities. Preventive interventions should consider innovative ways to foster societal integration within sexual minority populations and to adjust hetero-centric social institutions to better include sexual minorities.

Reduction in mental health treatment utilization among transgender individuals after gender-affirming surgeries: A total population study

Background

Despite professional recommendations to consider gender-affirming hormonal and surgical interventions for transgender individuals with gender dysphoria, the long-term effect of such interventions on mental health is largely unknown. This study aims to ascertain the prevalence of mood and anxiety disorder healthcare visits and antidepressant and anxiolytic prescriptions in 2015 as a function of gender dysphoria diagnosis and gender-affirming medical treatment in the entire Swedish population.

Methods

This study used the Swedish Total Population Register (n = 9,747,324), linked to the National Patient Register and Prescribed Drug Register. Among those who received a gender dysphoria diagnosis between 2005 and 2015 (n = 2,679), mental health treatment in 2015 was examined as a function of length of time since gender-affirming medical treatment. The main outcome measure was mood and anxiety disorder healthcare visits and antidepressant and anxiolytic prescriptions.

Results

Compared to the general population, individuals diagnosed with gender dysphoria were about six times as likely to have had a mood and anxiety disorder healthcare visit and more than three times as likely to have been prescribed antidepressants and anxiolytics. Years since initiating hormones was not significantly related to likelihood of mental health treatment (AOR: 1.01; 95% CI: 0.98, 1.03). However, increased time since last gender-affirming surgery was associated with reduced mental health treatment (AOR: 0.92; 95% CI: 0.87, 0.98).

Conclusions

In this first total population study of transgender individuals diagnosed with gender dysphoria, the longitudinal association between gender-affirming surgery and reduced likelihood of mental health treatment lends support to the decision to provide gender-affirming surgeries to transgender individuals who seek them.

Main messages: This study lends support to the decision to provide gender-affirming surgeries to transgender individuals who seek them.

The role of country-level structural stigma on sexual orientation disclosure and discrimination in health care settings among lesbian, gay, and bisexuals across Europe

Background

The national climate surrounding sexual minorities (i.e., those self-identifying as lesbian, gay, or bisexual [LGB]) varies greatly worldwide. Recent Cross-European studies have shown that country-level structural stigma is a strong determinant of sexual minority individuals health risk behaviors and mental health. The consequences of the significant country-level variation in structural stigma on sexual minorities’ experiences of health care discrimination and disclosure of sexual orientation to health care providers have not been previously investigated.

Methods

In 2012, 86 000 sexual minority individuals (aged 18 years and older) from all 28 European Union countries responded to questions concerning discrimination in health care settings and sexual orientation disclosure to health care providers (EU LGBT survey). Structural stigma was assessed using a combination of national laws and policies affecting sexual minorities and a measure of sexual minority acceptance among citizens of each country.

Results

Disclosure of sexual orientation to health care providers were much more common in low stigma coutries (e.g., the Netherlands, Sweden, UK) compared to high stigma coutries (e.g., Lithuania, Latvia, Slovakia). Experiences of discrimination in health care settings were more common among LGB indiviudals who were open about their sexual orientaiton and increased by degree of country-level structural stigma.

Conclusions

Disclosure of sexual orientation and experiences of discrimination in health care settings varies greatly among LGB individuals in Europe largely due to structural stigma surrounding sexual minorities.

Main messages

These findings highlight the importance of eliminating legislation, policies, and national attitudes that promote the unequal treatment of sexual minorities in currently unsupportive European countries.

Sexual orientation openness and depression symptoms: A population-based study

Background

Sexual minorities (e.g., lesbian, gay, and bisexual individuals) are at higher risk for depression than heterosexual individuals. Lack of openness about one’s sexual orientation is a suggested source of these disparities, but it has been linked to both positive and negative mental health. Few population-based studies have explored the association between openness and depression, and potential mediators and moderators of this association, including social support and sexual orientation-based victimization.

Methods

Swedish respondents to the 2014 wave of the European Health Interview Survey were used to identify a population-based sample of self-reported sexual minorities. All individuals reporting a nonheterosexual identity (and a matched sample of heterosexuals) were invited to participate in a follow-back study in 2016 (n = 320). A total of 191 (59.7%) individuals completed the survey, of whom 80 reported a gay, lesbian, bisexual, or other nonheterosexual identity.

Results

This first nationally representative survey of sexual orientation openness showed that only about one third of the sample reported being completely open. We found no evidence of a direct association between openness and depression or a mediating effect of social support or victimization on this association. However, social support moderated this relationship, such that greater openness was linked to higher depression among sexual minorities reporting low levels of social support.

Conclusions

Our study suggests that sexual orientation openness is not directly related to lower risk of depression among sexual minorities, but is instead dependent on access to social support. Sexual minorities might need social support for navigating the stress of open self-identification.

Short-term medical treatment of hypercalcaemia in primary hyperparathyroidism predicts symptomatic response after parathyroidectomy

Background

Primary hyperparathyroidism is often associated with non-disease-specific symptoms. The aim of this study was to evaluate whether normalization of hypercalcaemia with short-term medical treatment can be used to predict the effects of parathyroidectomy and guide in surgical decision-making.

Methods

This observational study included patients who received calcimimetic treatment for 4 weeks before parathyroidectomy (30–60 mg daily). A panel of tests was used to assess various aspects of quality of life (European Organisation and Treatment of Cancer QLQ-C30 core questionnaire, Hospital Anxiety and Depression Scale and Positive State of Mind questionnaire), cognitive function (Montreal Cognitive Assessment) and muscle strength (timed-stands test). The tests were carried out at baseline, after 4 weeks of calcimimetic treatment, and at 6 weeks and 6 months after parathyroidectomy. The predictive values of changes during calcimimetic treatment were determined for each test.

Results

The study included 110 patients of median age 62 years (91 women). Calcimimetic treatment resulted in normalization of calcium levels and improvements in quality-of-life parameters. The time spent on the timed-stands test was significantly shortened. Eleven of 38 participants with a baseline Montreal Cognitive Assessment score below 26, indicating mild cognitive impairment, reached scores of at least 26 during treatment with calcimimetic. Improvements during treatment with calcimimetic correlated well with postoperative outcomes (positive predictive values 74–96 per cent).

Conclusion

The method described in this study may be used to aid surgical decision-making for patients with primary hyperparathyroidism and non-disease-specific symptoms by predicting the effects of normalization of hypercalcaemia.

TERT Promoter Mutation Spatial Heterogeneity in a Metastatic Follicular Thyroid Carcinoma: Implications for Clinical Work-Up

Follicular thyroid carcinoma (FTC) is not routinely diagnosed by a preoperative fine needle aspiration biopsy (FNAB), and the final diagnosis relies on histopathological criteria visible upon microscopic examination of the excised tumor. Several markers have been proposed as helpful in the identification of follicular thyroid tumors with malignant potential and worse prognosis, of which the specific point mutations C250T and C228T in the Telomerase Reverse Transcriptase (TERT) promoter region seem to be particularly promising. We describe a patient presenting with a large pelvic mass, in which a core needle biopsy was consistent with follicular-patterned thyroid tissue positive for a Q61R NRAS mutation and the C228T TERT promoter mutation. Upon clinical investigation, a 60-mm lesion was detected in the right thyroid lobe. The ensuing FNAB was consistent with a follicular thyroid tumor, Bethesda IV, positive for the same NRAS mutation and both the C228T and C250T TERT promoter mutations. A total thyroidectomy was performed, and a widely invasive FTC was diagnosed. Tumor tissue samples from various parts of the primary lesion were investigated for TERT promoter mutations, displaying C228T in three samples and C250T in one. Interestingly, the C228T mutations showed a coupling to areas with high Ki-67 proliferation indexes. Our data indicate that TERT promoter mutations can exhibit spatial heterogeneity in FTCs, with implications for clinical management as well as providing insights into the molecular biology underlying the tumoral etiology.

Biochemical Inhibition of DOG1/TMEM16A Achieves Antitumoral Effects in Human Gastrointestinal Stromal Tumor Cells In Vitro

BACKGROUND/AIM

DOG1 is a calcium-activated chloride channel that has gained attention as a promising drug target due to its involvement in several processes essential for tumor development and progression. DOG1 is overexpressed in >95% of gastrointestinal stromal tumors (GIST). The aim was to determine DOG1 inhibition antitumoral effects on GIST.

MATERIALS AND METHODS

Human GIST (GIST-T1 and GIST882) cell lines were used to study the effect of DOG1 inhibitors on chloride currents, viability, colony formation, and cell cycle.

RESULTS

CaCC_inh-A01 decreased chloride currents. CaCC_inh-A01 and T16_inh-A01 reduced GIST cell viability and CaCC_inh-A01 affected cell cycle distribution leading to G₁ cell-cycle arrest. CaCC_inh-A01 also increased the sub-G₁ phase population, indicative of apoptosis, in GIST882. CaCC_inh-A01 strongly reduced the colony forming ability of the cells, whereas T16_inh-A01 did not.

CONCLUSION

DOG1 inhibition has antitumoral effects in GIST cells in vitro, and could potentially serve as a target for GIST therapy.

Abstract 1260: Inhibition of DOG1, or TMEM16A, results in antitumoral effects in gastrointestinal stromal tumors (GIST) in vitro

DOG1/TMEM16A, over-expressed in &gt;95% of all GISTs, is a calcium-activated chloride channel that has gained attention as a promising drug target due to its involvement in several tumor-physiological processes. Two well-established human GIST cell lines (GIST-T1 and GIST882) were used to study DOG1 inhibitors effect on viability, colony formation, and cell cycle. In this study, we show that specific DOG1/TMEM16A-inhibitors (T16inh-A01 and CaCCinh-A01) decrease chloride currents, and reduces cell viability in GIST cells. However, only CaCCinh-A01 changes the distribution of the cell cycle in GIST cells, putting them into G1 cell cycle arrest, and increases sub-G1 phase population in GIST882 cells. CaCCinh-A01 strongly reduces the colony forming ability of the cells, whereas limited effect by T16inh-A01. Conclusions: DOG1/TMEM16A inhibition has antitumoral effects in GIST cells in vitro, and could potentially serve as a target for GIST therapy. CaCCinh-A01 seems to be the more potent inhibitor, presumably due to its effect not only on chloride currents but also on DOG1/TMEM16A expression.

Citation Format: Robin Fröbom, Erik Berglund, Robert Bränström. Inhibition of DOG1, or TMEM16A, results in antitumoral effects in gastrointestinal stromal tumors (GIST) in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1260.

Clear Cell Variant of a Follicular Thyroid Tumor With Uncertain Malignant Potential: A Case Report

Follicular neoplasms of the thyroid gland are most often characterized by follicular-patterned thyrocytes with a neutrally stained cytoplasm, while a minority of cases present with oncocytic differentiation (Hürthle cell tumors). Exceedingly rare variants with a clear cell phenotype have also been reported, both as clear cell follicular thyroid adenomas (ccFTAs) and clear cell follicular carcinomas (ccFTCs). We present a patient with a 30-mm lesion in the thyroid isthmus in which the preoperative cytology proposed a follicular tumor. On postoperative histopathological evaluation, the tumor surprisingly displayed uniform clear-cell differentiation. No nuclear features suggestive of papillary thyroid carcinoma were observed, and differential diagnoses such as medullary thyroid carcinoma, metastatic renal cell, and parathyroid carcinoma were ruled out. The histological investigation revealed intracapsular collections of tumor cells displaying a debatable relation to the surrounding capsule and blood vessels, and the final diagnosis was a follicular tumor of uncertain malignant potential (FT-UMP) as defined by the WHO 2017 classification. As subsets of FT-UMPs with TERT promoter mutations do recur as advanced malignant tumors, a sequencing analysis was undertaken but could not identify TERT promoter mutations at position C228 or C250. To our knowledge, no previous literature has described a clear cell phenotype in an FT-UMP. We therefore advocate that endocrine pathologists should be aware of this entity in addition to ccFTAs and ccFTCs.

Wide Surgical Margin Improves the Outcome for Patients with Gastrointestinal Stromal Tumors (GISTs)

Background

Surgical resection is still the main treatment for gastrointestinal stromal tumor (GIST), and R0 excision, regardless of surgical margins, is considered sufficient.

Methods

A cohort of 79 consecutive GIST cases treated at the Karolinska University Hospital, who were without metastasis at diagnosis and who had not received any pre-or postoperative treatment with tyrosine kinase inhibitors, was included. Surgical margins were evaluated at the time of surgery and classified as wide, marginal or intralesional. Time to local/peritoneal recurrence, distant metastasis, and survival were recorded. Cox regression analysis was used to investigate the association between surgical margin, and recurrence and survival.

Results

Local/peritoneal recurrence was diagnosed in 2/39 cases with wide margins, in 7/22 cases with marginal margins, and in 13/18 cases with intralesional surgery. Compared to wide margins this gives a hazard ratio of 6.8 (confidence interval 1.4–32.7) for marginal margins and 13.5 (3–61) for intralesional margins. In multivariate analysis, adjusting for size, site, and mitotic index, surgical margin remained an independent significant predictor of risk for recurrence. When classifying patients according to R0/R1 surgery, patients with R0 surgery showed longer time to peritoneal recurrence and better recurrence-free and disease-specific survival as compared to those with R1 resection. However, when excluding patients operated with wide surgical margin, no significant difference was observed.

Conclusion

Wide surgical margins are of significant prognostic importance, supporting the strategy of en bloc resection with good margin and careful handling of the tumor to avoid damaging the peritoneal surface in surgical resection of GIST.

Electronic supplementary material

The online version of this article (10.1007/s00268-018-4498-9) contains supplementary material, which is available to authorized users.

miR-125a-5p regulation increases phosphorylation of FAK that contributes to imatinib resistance in gastrointestinal stromal tumors

The use of imatinib mesylate has greatly improved the clinical outcome for gastrointestinal stromal tumor (GIST) patients. However, imatinib resistance is still a major clinical challenge, and the molecular mechanisms are not fully understood. We have previously shown that miR-125a-5p and its mRNA target PTPN18 modulate imatinib response in GIST cells. Herein, we evaluated phosphorylated FAK (pFAK) as a candidate downstream target of PTPN18 and the possible association of this regulation with imatinib resistance in GIST. FAK and pFAK expressions were evaluated in GIST882 cells transfected with short hairpin RNA or short interfering RNA targeting PTPN18 or miR-125a-5p mimic, imatinib-resistant GIST882R subclones and clinical samples using Western blot analyses. FAK phosphorylation was blocked using the FAK inhibitor 14 (FAKi) and the effects on cell viability and apoptosis were evaluated using WST-1 assay and cleaved PARP expression. Clinical associations of FAK and pFAK expression with imatinib resistance, KIT mutation and patient outcome were assessed by Fisher's exact test or log-rank test. Over-expression of miR-125a-5p and silencing of PTPN18 increased pFAK, but not FAK, expression in GIST cells. Higher pFAK expression was observed in the GIST882R subclones with acquired imatinib resistance compared to their imatinib-sensitive parental cells. Treatment with FAKi in imatinib-resistant GIST882R cells reduced cell viability and increased apoptosis upon imatinib treatment. Additionally, FAKi could rescue the imatinib resistance effect mediated by miR-125a-5p over-expression. In clinical samples, high FAK and pFAK expressions were associated with KIT mutation status, and high FAK expression was also associated with metastasis in GIST. Higher pFAK was found in cases with shorter overall survival. Our findings highlight an important role for miR-125a-5p regulation and its downstream target pFAK for imatinib resistance in GIST. pFAK and FAK may have prognostic values in GIST.

Expression, purification, and electrophysiological characterization of a recombinant, fluorescent Kir6.2 in mammalian cells

The inwardly rectifying K⁺ (Kir) channel, Kir6.2, plays critical roles in physiological processes in the brain, heart, and pancreas. Although Kir6.2 has been extensively studied in numerous expression systems, a comprehensive description of an expression and purification protocol has not been reported. We expressed and characterized a recombinant Kir6.2, with an N-terminal decahistidine tag, enhanced green fluorescent protein (eGFP) and deletion of C-terminal 26 amino acids, in succession, denoted eGFP-Kir6.2Δ26. eGFP-Kir6.2Δ26 was expressed in HEK293 cells and a purification protocol developed. Electrophysiological characterization showed that eGFP-Kir6.2Δ26 retains native single channel conductance (64 ± 3.3 pS), mean open times (τ₁ = 0.72 ms, τ₂ = 15.3 ms) and ATP affinity (IC₅₀ = 115 ± 25 μM) when expressed in HEK293 cells. Detergent screening using size exclusion chromatography (SEC) identified Fos-choline-14 (FC-14) as the most suitable surfactant for protein solubilization, as evidenced by maintenance of the native tetrameric structure in SDS-PAGE and western blot analysis. A two-step scheme using Co²⁺-metal affinity chromatography and SEC was implemented for purification. Purified protein activity was assessed by reconstituting eGFP-Kir6.2Δ26 in black lipid membranes (BLMs) composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG), l-α-phosphatidylinositol-4,5-bisphosphate (PIP₂) in a 89.5:10:0.5 mol ratio. Reconstituted eGFP-Kir6.2Δ26 displayed similar single channel conductance (61.8 ± 0.54 pS) compared to eGFP-Kir6.2Δ26 expressed in HEK293 membranes; however, channel mean open times increased (τ₁ = 7.9 ms, τ₂ = 61.9 ms) and ATP inhibition was significantly reduced for eGFP-Kir6.2Δ26 reconstituted into BLMs (IC₅₀ = 3.14 ± 0.4 mM). Overall, this protocol should be foundational for the production of purified Kir6.2 for future structural and biochemical studies.

Methacrylate Polymer Scaffolding Enhances the Stability of Suspended Lipid Bilayers for Ion Channel Recordings and Biosensor Development

Black lipid membranes (BLMs) provide a synthetic environment that facilitates measurement of ion channel activity in diverse analytical platforms. The limited electrical, mechanical and temporal stabilities of BLMs pose a significant challenge to development of highly stable measurement platforms. Here, ethylene glycol dimethacrylate (EGDMA) and butyl methacrylate (BMA) were partitioned into BLMs and photopolymerized to create a cross-linked polymer scaffold in the bilayer lamella that dramatically improved BLM stability. The commercially available methacrylate monomers provide a simple, low cost, and broadly accessible approach for preparing highly stabilized BLMs useful for ion channel analytical platforms. When prepared on silane-modified glass microapertures, the resulting polymer scaffold-stabilized (PSS)-BLMs exhibited significantly improved lifetimes of 23 ± 9 to 40 ± 14 h and > 10-fold increase in mechanical stability, with breakdown potentials > 2000 mV attainable, depending on surface modification and polymer cross-link density. Additionally, the polymer scaffold exerted minimal perturbations to membrane electrical integrity as indicated by mean conductance measurements. When gramicidin A and α-hemolysin were reconstituted into PSS-BLMs, the ion channels retained function comparable to conventional BLMs. This approach is a key advance in the formation of stabilized BLMs and should be amenable to a wide range of receptor and ion channel functionalized platforms.

Sporadic multiple parathyroid gland disease--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Sporadic multiglandular disease (MGD) has been reported in literature in 8-33 % of patients with primary hyperparathyroidism (pHPT). This paper aimed to review controversies in the pathogenesis and management of sporadic MGD.

METHODS

A literature search and review was made to evaluate the level of evidence concerning diagnosis and management of sporadic MGD according to criteria proposed by Sackett, with recommendation grading by Heinrich et al. and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled 'Hyperparathyroidism due to multiple gland disease: An evidence-based perspective'.

RESULTS

Literature reports no prospective randomised studies; thus, a relatively low level of evidence was achieved. Appropriate surgical therapy of sporadic MGD should consist of a bilateral approach in most patients. Unilateral neck exploration guided by preoperative imaging should be reserved for selected patients, performed by an experienced endocrine surgeon and monitored by intraoperative parathormone assay (levels of evidence III-V, grade C recommendation). There is conflicting or equally weighted levels IV-V evidence supporting that cure rates can be similar or worse for sporadic MGD than for single adenomas (no recommendation). Best outcomes can be expected if surgery is performed by an experienced parathyroid surgeon working in a high-volume centre (grade C recommendation). Levels IV-V evidence supports that recurrent/persistence pHPT occurs more frequently in patients with double adenomas hence in situations where a double adenoma has been identified, the surgeon should have a high index of suspicion during surgery and postoperatively for the possibility of a four-gland disease (grade C recommendation).

CONCLUSIONS

Identifying preoperatively patients at risk for MGD remains challenging, intraoperative decisions are important for achieving acceptable cure rates and long-term follow-up is mandatory in such patients.

microRNA expression signatures of gastrointestinal stromal tumours: associations with imatinib resistance and patient outcome

BACKGROUND

Gastrointestinal stromal tumour (GIST) is mainly initialised by receptor tyrosine kinase gene mutations. Although the tyrosine kinase inhibitor imatinib mesylate considerably improved the outcome of patients, imatinib resistance still remains a major therapeutic challenge in GIST therapy. Herein we evaluated the clinical impact of microRNAs in imatinib-treated GISTs.

METHODS

The expression levels of microRNAs were quantified using microarray and RT-qPCR in GIST specimens from patients treated with neoadjuvant imatinib. The functional roles of miR-125a-5p and PTPN18 were evaluated in GIST cells. PTPN18 expression was quantified by western blotting in GIST samples.

RESULTS

We showed that overexpression levels of miR-125a-5p and miR-107 were associated with imatinib resistance in GIST specimens. Functionally, miR-125a-5p expression modulated imatinib sensitivity in GIST882 cells with a homozygous KIT mutation but not in GIST48 cells with double KIT mutations. Overexpression of miR-125a-5p suppressed PTPN18 expression, and silencing of PTPN18 expression increased cell viability in GIST882 cells upon imatinib treatment. PTPN18 protein levels were significantly lower in the imatinib-resistant GISTs and inversely correlated with miR-125a-5p. Furthermore, several microRNAs were significantly associated with metastasis, KIT mutational status and survival.

CONCLUSIONS

Our findings highlight a novel functional role of miR-125a-5p on imatinib response through PTPN18 regulation in GIST.