Cost-Effectiveness of Parathyroid Cryopreservation and Autotransplantation

Importance

Delayed autotransplantation of cryopreserved parathyroid tissue (DACP) is the only surgical treatment for permanent postoperative hypoparathyroidism. Studies suggest that only a small minority of cryopreserved samples are ultimately autotransplanted with highly variable outcomes. For these reasons, many have questioned the economic utility of the process, although, to the authors' knowledge, this has never been formally studied.

Objective

To report the clinical outcomes of parathyroid cryopreservation and DACP at a large academic institution and to determine the cost-effectiveness of this treatment.

Design, Setting, and Participants

An institutional review board-approved, retrospective review of patients at a single institution who underwent DACP over a 17-year period was conducted with a median follow-up of 48.2 months. A forward-looking cost-utility analysis was then performed to determine the economic utility of cryopreservation/DACP vs usual care (monitoring and supplementation). Patients who had parathyroid tissue in cryopreserved storage between August 2005 to September 2022 at a single-center, academic, quaternary care center were identified.

Exposure

Parathyroid cryopreservation and DACP.

Main Outcomes and Measures

Graft functionality, clinical outcomes, and cost utility using a willingness-to-pay threshold of $100 000 per quality-adjusted life-year (QALY).

Results

A total of 591 patients underwent cryopreservation. Of these, 10 patients (1.7%; mean [SD] age, 45.6 [17.9] years; 6 male [60%]) underwent DACP. A minority of autografts (2 [20%]) were subsequently fully functional, one-half (5 [50%]) were partially functional, and 3 (30%) were not functional. The cost-utility model estimated that at a large academic center over 10 years, the additional cost of 591 patients undergoing cryopreservation and 10 patients undergoing autotransplantation would be $618 791.64 (2022 dollars) and would add 8.75 QALYs, resulting in a cost per marginal QALY of $70 719.04, which is less than the common willingness-to-pay threshold of $100 000/QALY.

Conclusions and Relevance

The reimplantation rate of cryopreserved tissue was low (<2%), but when implanted, autografts were at least partially functional 70% of the time. In the first-ever, to the authors' knowledge, formal cost analysis for this treatment, results of the current model suggest that cryopreservation and autotransplantation were cost-effective compared with the usual care for hypoparathyroidism at a large, academic institution. It is recommended that each surgical center consider whether the economic and logistical commitments necessary for cryopreservation are worthwhile for their individual needs.

Molecular characteristics of isthmus papillary thyroid cancers: Supporting evidence for unfavorable clinical behavior

BACKGROUND

Previous studies demonstrate isthmus thyroid nodules are more likely to be malignant than lobar nodules. Additional data suggest that isthmus papillary thyroid cancers (PTCs) are more aggressive than lobar PTCs. We hypothesize that isthmus PTCs have a more unfavorable molecular profile.

METHODS

The Cancer Genome Atlas (TCGA) database was queried to analyze clinical, mutation and gene expression data of isthmus PTCs compared to non-isthmus PTCs.

RESULTS

We analyzed characteristics of 472 ​PTCs, including 19 isthmus PTCs. There were no significant differences between isthmus and non-isthmus PTC demographic and clinical variables or the frequency of RAS family, fusion driver, TERT, and tumor suppressor gene mutations. There was a trend towards increased BRAF mutations (68% vs 55%, p ​= ​0.28). A more aggressive gene expression profile was observed in isthmus PTC compared to lobar/multifocal PTC with differences in ERK score (19.4 vs 7.71, p ​< ​0.05) and TDS score (-0.58 vs 0.02, p ​< ​0.05).

CONCLUSIONS

These results provide a possible molecular explanation for the more aggressive behavior reported in isthmus PTCs.

Analysis of Preoperative Predictors of Single and Multigland Primary Hyperparathyroidism

INTRODUCTION

Preoperative differentiation of single-gland (SG) versus multigland (MG) primary hyperparathyroidism (PHPT) can assist with surgical planning, treatment prognostication, and patient counseling. The aim of this study was to identify preoperative predictors of SG-PHPT.

METHODS

Retrospective analysis of 408 patients with PHPT who underwent parathyroidectomy at a tertiary referral center. Comprehensive preoperative parameters, including demographic, laboratory, clinical, and imaging results were analyzed. Univariate analysis and binary logistic regression identified preoperative predictors of SG-PHPT. Receiver operator curves were used to analyze the predictive values of existing and novel preoperative predictive models.

RESULTS

Elevated parathyroid hormone (PTH) (99.1 pg/mL in SG versus 93.0 pg/mL in MG), elevated calcium (10.8 mg/dL in SG versus 10.6 mg/dL in MG), lower phosphate levels (2.80 mg/dL in SG versus 2.95 mg/dL in MG), and positive imaging (ultrasound 75.6% in SG versus 56.5% in MG; sestamibi 70.8% in SG versus 45.5% in MG) were significantly associated with SG-PHPT. The Washington University Score (a predictive scoring system made from calcium, PTH, phosphate, ultrasound, and sestamibi) and the Washington University Index ([calcium × PTH]/phosphate) were comparable to previous scoring systems used to predict SG versus MG-PHPT.

CONCLUSIONS

The association of lower phosphate with SG-PHPT is a novel finding. Previously identified predictors of SG-PHPT, including elevated PTH and positive imaging were confirmed. The Washington University Score and Index are comparable to previously described models and can be used to help surgeons predict if a patient may have SG versus MG-PHPT.

Cytosolic EpCAM cooperates with H-Ras to regulate epithelial to mesenchymal transition through ZEB1

Next generation sequencing of human cancer mutations has identified novel therapeutic targets. Activating Ras oncogene mutations play a central role in oncogenesis, and Ras-driven tumorigenesis upregulates an array of genes and signaling cascades that can transform normal cells into tumor cells. In this study, we investigated the role of altered localization of epithelial cell adhesion molecule (EpCAM) in Ras-expressing cells. Analysis of microarray data demonstrated that Ras expression induced EpCAM expression in normal breast epithelial cells. Fluorescent and confocal microscopy showed that H-Ras mediated transformation also promoted epithelial-to-mesenchymal transition (EMT) together with EpCAM. To consistently localize EpCAM in the cytosol, we generated a cancer-associated EpCAM mutant (EpCAM-L240A) that is retained in the cytosol compartment. Normal MCF-10A cells were transduced with H-Ras together with EpCAM wild-type (WT) or EpCAM-L240A. WT-EpCAM marginally effected invasion, proliferation, and soft agar growth. EpCAM-L240A, however, markedly altered cells and transformed to mesenchymal phenotype. Ras-EpCAM-L240A expression also promoted expression of EMT factors FRA1, ZEB1 with inflammatory cytokines IL-6, IL-8, and IL1. This altered morphology was reversed using MEK-specific inhibitors and to some extent JNK inhibition. Furthermore, these transformed cells were sensitized to apoptosis using paclitaxel and quercetin, but not other therapies. For the first time, we have demonstrated that EpCAM mutations can cooperate with H-Ras and promote EMT. Collectively, our results highlight future therapeutic opportunities in EpCAM and Ras mutated cancers.

GCM2 Variants in Familial and Multiglandular Primary Hyperparathyroidism

CONTEXT

Multiglandular and familial parathyroid disease constitute important fractions of primary hyperparathyroidism (PHPT). Germline missense variants of GCM2, a regulator of parathyroid development, were observed in familial isolated hyperparathyroidism and sporadic PHPT. However, as these previously reported GCM2 variants occur at relatively high frequencies in the population, understanding their potential clinical utility will require both additional penetrance data and functional evidence relevant to tumorigenicity.

OBJECTIVE

Determine the frequency of GCM2 variants of interest among patients with sporadic multigland or familial parathyroid disease and assess their penetrance.

DESIGN AND PATIENTS

DNA-encoding PHPT-associated GCM2 germline variants were polymerase chain reaction-amplified and sequenced from 107 patients with either sporadic multigland or suspected/confirmed familial parathyroid tumors.

RESULTS

GCM2 variants were observed in 9 of 107 cases (8.4%): Y282D in 4 patients (6.3%) with sporadic multigland disease; Y394S in 2 patients (11.1%) with familial PHPT and 3 (4.8%) with sporadic multigland disease. Compared with the general population, Y282D was enriched 5.9-fold in multigland disease, but its penetrance was very low (0.02%). Y394S was enriched 79-fold in sporadic multigland disease and 93-fold in familial PHPT, but its penetrance was low (1.33% and 1.04%, respectively).

CONCLUSIONS

Observed in vitro-activating GCM2 variant alleles are significantly overrepresented in PHPT patients with multiglandular or familial disease compared to the general population, yet penetrance values are very low; that is, most individuals with these variants in the population have a very low risk of developing PHPT. The potential clinical utility of detecting these GCM2 variants requires further investigation, including assessing their possible role as pathogenic/low-penetrance alleles.

Cancer-associated mutations reveal a novel role for EpCAM as an inhibitor of cathepsin-L and tumor cell invasion

Background

EpCAM (Epithelial cell adhesion molecule) is often dysregulated in epithelial cancers. Prior studies implicate EpCAM in the regulation of oncogenic signaling pathways and epithelial-to-mesenchymal transition. It was recently demonstrated that EpCAM contains a thyroglobulin type-1 (TY-1) domain. Multiple proteins with TY-1 domains are known to inhibit cathepsin-L (CTSL), a cysteine protease that promotes tumor cell invasion and metastasis. Analysis of human cancer sequencing studies reveals that somatic EpCAM mutations are present in up to 5.1% of tested tumors.

Methods

The Catalogue of Somatic Mutations in Cancer (COSMIC) database was queried to tabulate the position and amino acid changes of cancer associated EpCAM mutations. To determine how EpCAM mutations affect cancer biology we studied C66Y, a damaging TY-1 domain mutation identified in liver cancer, as well as 13 other cancer-associated EpCAM mutations. In vitro and in vivo models were used to determine the effect of wild type (WT) and mutant EpCAM on CTSL activity and invasion. Immunoprecipitation and localization studies tested EpCAM and CTSL protein binding and determined compartmental expression patterns of EpCAM mutants.

Results

We demonstrate that WT EpCAM, but not C66Y EpCAM, inhibits CTSL activity in vitro, and the TY-1 domain of EpCAM is responsible for this inhibition. WT EpCAM, but not C66Y EpCAM, inhibits tumor cell invasion in vitro and lung metastases in vivo. In an extended panel of human cancer cell lines, EpCAM expression is inversely correlated with CTSL activity. Previous studies have demonstrated that EpCAM germline mutations can prevent EpCAM from being expressed at the cell surface. We demonstrate that C66Y and multiple other EpCAM cancer-associated mutations prevent surface expression of EpCAM. Cancer-associated mutations that prevent EpCAM cell surface expression abrogate the ability of EpCAM to inhibit CTSL activity and tumor cell invasion.

Conclusions

These studies reveal a novel role for EpCAM as a CTSL inhibitor, confirm the functional relevance of multiple cancer-associated EpCAM mutations, and suggest a therapeutic vulnerability in cancers harboring EpCAM mutations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08239-z.

PIK3CA Mutational Analysis of Parathyroid Adenomas

Benign parathyroid adenoma is the most common cause of primary hyperparathyroidism, whereas malignant parathyroid carcinoma is exceedingly rare. Distinguishing parathyroid carcinoma from benign adenoma is often difficult, and may be considerably delayed even after surgical resection until the rigorous diagnostic criteria of local invasion of surrounding tissues and/or distant metastases are fulfilled. Thus, new insights into their respective molecular bases may potentially aid in earlier diagnostic discrimination between the two, as well as informing new directions for treatment. In two recent studies, gain‐of‐function mutations in PIK3CA, a recognized driver oncogene in many human malignancies, have been newly identified in parathyroid carcinoma. To assess the potential specificity for malignant, as opposed to benign parathyroid disease, of PIK3CA hotspot mutations, we PCR‐amplified and Sanger sequenced codons 111, 542/545, and 1047 and the immediate flanking regions in genomic DNA from 391 typical, sporadic parathyroid adenomas. Four parathyroid adenomas (1%) had subclonal, somatic, heterozygous, activating PIK3CA mutations. The rarity of PIK3CA activating mutations in benign parathyroid adenomas suggests that tumorigenic activation of PIK3CA is strongly associated with malignant parathyroid neoplasia. However, it does not appear that such mutations, at least in isolation, can be relied upon for definitive molecular diagnosis of parathyroid carcinoma. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Recurrent Amplification of the Osmotic Stress Transcription Factor NFAT5 in Adrenocortical Carcinoma

Tumorigenesis requires mitigation of osmotic stress and the transcription factor nuclear factor of activated T cells 5 (NFAT5) coordinates this response by inducing transcellular transport of ions and osmolytes. NFAT5 modulates in vitro behavior in several cancer types, but a potential role of NFAT5 in adrenocortical carcinoma (ACC) has not been studied. A discovery cohort of 28 ACCs was selected for analysis. Coverage depth analysis of whole-exome sequencing reads assessed NFAT5 copy number alterations in 19 ACCs. Quantitative real-time PCR measured NFAT5 mRNA expression levels in 11 ACCs and 23 adrenocortical adenomas. Immunohistochemistry investigated protein expression in representative adrenal samples. The Cancer Genome Atlas database was analyzed to corroborate NFAT5 findings from the discovery cohort and to test whether NFAT5 expression correlated with ion/osmolyte channel and regulatory protein expression patterns in ACC. NFAT5 was amplified in 10 ACCs (52.6%) and clustered in the top 6% of all amplified genes. mRNA expression levels were 5-fold higher compared with adrenocortical adenomas (P < 0.0001) and NFAT5 overexpression had a sensitivity and specificity of 81.8% and 82.7%, respectively, for malignancy. Increased protein expression and nuclear localization occurred in representative ACCs. The Cancer Genome Atlas analysis demonstrated concomitant NFAT5 amplification and overexpression (P < 0.0001) that correlated with increased expression of sodium/myo-inositol transporter SLC5A3 (r² = 0.237, P < 0.0001) and 14 other regulatory proteins (P < 0.05) previously shown to interact with NFAT5. Amplification and overexpression of NFAT5 and associated osmotic stress response related genes may play an important role adrenocortical tumorigenesis.

Immune cell infiltrate-associated dysregulation of DNA repair machinery may predispose to papillary thyroid carcinogenesis

BACKGROUND

An altered immune microenvironment may contribute to papillary thyroid cancer development, as immune infiltrates are identified postoperatively in many papillary thyroid cancer cases with or without diagnosed thyroiditis. Oxygen radicals, endogenous or inflammation-induced, can generate DNA damage, which causes mutations when repaired incorrectly. We hypothesized that infiltrating immune cells might promote aberrant DNA repair, predisposing thyrocytes to papillary thyroid cancer.

METHODS

Quantitative reverse-transcriptase polymerase chain reaction assays measured gene expression in fresh-frozen samples (n = 55). RNA-seq data was obtained for papillary thyroid cancer and normal thyroid samples from the Cancer Genome Atlas (n = 564), and Hashimoto's-affected and normal thyroids from the Genotype-Tissue Expression project (n = 279). Immune cell marker expression levels were compared to histological estimates and to selected DNA repair genes. Immunohistochemistry localized gene expression to specific cell types.

RESULTS

DNA polymerase theta expression by quantitative reverse-transcriptase Polymerase chain reaction was higher in papillary thyroid cancer and papillary thyroid cancer-adjacent samples than in benign normal thyroid (P < .001). Immune markers including CD4 correlated with DNA polymerase theta expression (r = 0.50) but not other DNA repair genes examined. Benign tissue with Hashimoto's exhibited increased DNA polymerase theta (P < .0001) and CD3E (P < .0001) expression. DNA polymerase theta localized to thyrocytes, not lymphocytes.

CONCLUSION

We identified a strong correlation between immune cell infiltrate and dysregulated thyrocyte DNA repair genes, likely reflecting a pathway to papillary thyroid cancer development.

Analysis of Activating GCM2 Sequence Variants in Sporadic Parathyroid Adenomas

CONTEXT

Sporadic, solitary parathyroid adenoma is the most common cause of primary hyperparathyroidism (PHPT). Apart from germline variants in certain cyclin-dependent kinase inhibitor genes and occasionally in MEN1, CASR, or CDC73, little is known about possible genetic variants in the population that may confer increased risk for development of typical sporadic adenoma. Transcriptionally activating germline variants, especially within in the C-terminal conserved inhibitory domain (CCID) of glial cells missing 2 (GCM2), encoding a transcription factor required for parathyroid gland development, have recently been reported in association with familial and sporadic PHPT.

OBJECTIVE

To evaluate the potential role of specific GCM2 activating variants in sporadic parathyroid adenoma.

DESIGN AND PATIENTS

Regions encoding hyperparathyroidism-associated, activating GCM2 variants were PCR amplified and sequenced in genomic DNA from 396, otherwise unselected, cases of sporadic parathyroid adenoma.

RESULTS

Activating GCM2 CCID variants (p.V382M and p.Y394S) were identified in six of 396 adenomas (1.52%), and a hyperparathyroidism-associated GCM2 non-CCID activating variant (p.Y282D) was found in 20 adenomas (5.05%). The overall frequency of tested activating GCM2 variants in this study was 6.57%, approximately threefold greater than their frequency in the general population.

CONCLUSIONS

The examined, rare CCID variants in GCM2 were enriched in our cohort of patients and appear to confer a moderately increased risk of developing sporadic solitary parathyroid adenoma compared with the general population. However, penetrance of these variants is low, suggesting that the large majority of individuals with such variants will not develop a sporadic parathyroid adenoma.

Insulin-Like Growth Factor and SLC12A7 Dysregulation: A Novel Signaling Hallmark of Non-Functional Adrenocortical Carcinoma

BACKGROUND

Insulin-like growth factor (IGF) dysregulation and gene copy number variations (CNV) are hallmarks of adrenocortical carcinoma (ACC). The contribution of IGF CNVs in adrenal carcinogenesis has not been studied previously. In addition, studies demonstrating an association between SLC12A7 gene amplifications and enhanced metastatic behavior in ACC, as well as reported IGF-SLC12A7 signaling interactions in other cancers, suggest a potential IGF-SLC12A7 signaling circuitry in ACC. Here we investigate the potential complicity of IGF-SLC12A7 signaling in ACC.

STUDY DESIGN

Insulin-like growth factor CNVs were determined by whole-exome sequencing analysis in an exploratory cohort of ACC. Quantitative polymerase chain reaction methods determined IGF1 and IGF2 expression levels and were evaluated for correlation with SLC12A7 expression and tumor characteristics. Insulin-like growth factor CNVs and expression patterns were compared with The Cancer Genome Atlas. In vitro studies determined the relationship of IGF and SLC12A7 co-expression in 2 ACC cell lines, SW-13 and NCI-H295R. Immunohistochemistry assessed IGF1 receptor (IGF1R) activation.

RESULTS

The IGF1 gene was amplified in 9 of 19 ACC samples, similar to findings in The Cancer Genome Atlas database. The IGF1 overexpression was observed in 5 samples and was associated with SLC12A7 overexpression and non-functional, early-stage tumors (p < 0.05). In contrast, IGF2 overexpression was associated with larger tumors (p < 0.05). In vitro IGF treatment of ACC cell lines did not stimulate SLC12A7 expression, and endogenous overexpression and silencing of SLC12A7 significantly altered IGF1 and IGF1R expression without impacting other IGFs. The IGF1R activation was associated with IGF1 overexpression in ACC tumor samples.

CONCLUSIONS

These findings indicate that IGF1 overexpression, caused in part by gene amplifications, is correlated with SLC12A7 overexpression in non-functional, early-stage ACCs, suggesting a potentially targeted IGF1-SLC12A7 therapeutic opportunity for these tumors.

Comprehensive Genetic Analysis of Follicular Thyroid Carcinoma Predicts Prognosis Independent of Histology

CONTEXT

Follicular thyroid carcinoma (FTC) is classified into minimally invasive (miFTC), encapsulated angioinvasive (eaFTC), and widely invasive (wiFTC) subtypes, according to the 2017 World Health Organization guidelines. The genetic signatures of these subtypes may be crucial for diagnosis, prognosis, and treatment but have not been described.

OBJECTIVE

Identify and describe the genetic underpinnings of subtypes of FTC.

METHODS

Thirty-nine tumors, comprising 12 miFTCs, 17 eaFTCs, and 10 wiFTCs, were whole-exome sequenced and analyzed. Somatic mutations, constitutional sequence variants, somatic copy number alterations, and mutational signatures were described. Clinicopathologic parameters and mutational profiles were assessed for associations with patient outcomes.

RESULTS

Total mutation burden was consistent across FTC subtypes, with a median of 10 (range 1 to 44) nonsynonymous somatic mutations per tumor. Overall, 20.5% of specimens had a mutation in the RAS subfamily (HRAS, KRAS, or NRAS), with no notable difference between subtypes. Mutations in TSHR, DICER1, EIF1AX, KDM5C, NF1, PTEN, and TP53 were also noted to be recurrent across the cohort. Clonality analysis demonstrated more subclones in wiFTC. Survival analysis demonstrated worse disease-specific survival in the eaFTC and wiFTC cohorts, with no recurrences or deaths for patients with miFTC. Mutation burden was associated with worse prognosis, independent of histopathological classification.

CONCLUSIONS

Though the number and variety of somatic variants are similar in the different histopathological subtypes of FTC in our study, mutational burden was an independent predictor of mortality and recurrence.

SLC12A7 alters adrenocortical carcinoma cell adhesion properties to promote an aggressive invasive behavior

BACKGROUND

Altered expression of Solute Carrier Family 12 Member 7 (SLC12A7) is implicated to promote malignant behavior in multiple cancer types through an incompletely understood mechanism. Recent studies have shown recurrent gene amplifications and overexpression of SLC12A7 in adrenocortical carcinoma (ACC). The potential mechanistic effect(s) of SLC12A7 amplifications in portending an aggressive behavior in ACC has not been previously studied and is investigated here using two established ACC cell lines, SW-13 and NCI-H295R.

METHODS

SW-13 cells, which express negligible amounts of SLC12A7, were enforced to express SLC12A7 constitutively, while RNAi gene silencing was performed in NCI-H295R cells, which have robust endogenous expression of SLC12A7. In vitro studies tested the outcomes of experimental alterations in SLC12A7 expression on malignant characteristics, including cell viability, growth, colony formation potential, motility, invasive capacity, adhesion and detachment kinetics, and cell membrane organization. Further, potential alterations in transcription regulation downstream to induced SLC12A7 overexpression was explored using targeted transcription factor expression arrays.

RESULTS

Enforced SLC12A7 overexpression in SW-13 cells robustly promoted motility and invasive characteristics (p < 0.05) without significantly altering cell viability, growth, or colony formation potential. SLC12A7 overexpression also significantly increased rates of cellular attachment and detachment turnover (p < 0.05), potentially propelled by increased filopodia formation and/or Ezrin interaction. In contrast, RNAi gene silencing of SLC12A7 stymied cell attachment strength as well as migration and invasion capacity in NCI-H295R cells. Transcription factor expression analysis identified multiple signally pathways potentially affected by SLC12A7 overexpression, including osmotic stress, bone morphogenetic protein, and Hippo signaling pathways.

CONCLUSIONS

Amplification of SLC12A7 observed in ACCs is shown here, in vitro, to exacerbate the malignant behavior of ACC cells by promoting invasive capacities, possibly mediated by alterations in multiple signaling pathways, including the osmotic stress pathway.

Characterization of Cell Membrane Extensions and Studying Their Roles in Cancer Cell Adhesion Dynamics

The cell membrane's extension repertoire modulates various malignant behaviors of cancer cells, including their adhesive and migratory potentials. The ability to accurately classify and quantify cell extensions and measure the effect on a cell's adhesive capacity is critical to determining how cell-signaling events impact cancer cell behavior and aggressiveness. Here, we describe the in vitro design and use of a cell extension quantification method in conjunction with an adhesion capacity assay in an established in vitro model for adrenocortical carcinoma (ACC). Specifically, we test the effects of DKK3, a putative tumor suppressor and a pro-differentiation factor, on the membrane extension phenotype of the ACC cell line, SW-13. We propose these assays to provide relatively simple, reliable, and easily interpretable metrics to measures these characteristics under various experimental conditions.

BCL9 Upregulation in Adrenocortical Carcinoma: A Novel Wnt/β-Catenin Activating Event Driving Adrenocortical Malignancy

BACKGROUND

B-Cell CLL/Lymphoma 9 (BCL9) is a recently described oncogene that promotes tumorigenesis via activation of the Wnt/β-Catenin signaling cascade. Though constitutively active Wnt/β-Catenin signaling is a molecular hallmark of adrenocortical carcinoma (ACC), a potential role for BCL9 to promote Wnt/β-Catenin pathway dysregulation in adrenocortical tumorigenesis remains to be elucidated.

STUDY DESIGN

This study involved a retrospective analysis at a tertiary academic referral center of 27 patients with adrenocortical tumors, including in vitro investigation of BCL9. The Wnt signaling pathway polymerase chain reaction (PCR) array analysis queried comparative mRNA expression profiles of canonical Wnt pathway components including BCL9. Real-time quantitative PCR determined BCL9 mRNA expression levels in tumor samples. Expression levels of BCL9 mRNA were evaluated for correlation with tumor characteristics. RNA interference (RNAi) gene silencing was performed in ACC cell lines SW-13 and NCI-H295R to test the role of BCL9 on clonal cell growth.

RESULTS

Expression levels of the BCL9 gene were found to be significantly elevated in ACC compared with normal adrenal tissue (p < 0.05). Furthermore, a significant correlation was observed between BCL9 mRNA levels and the malignant status of adrenocortical tumors (p < 0.05). RNAi gene silencing of BCL9 inhibited clonal cell growth of SW-13 cells (p < 0.05), but not NCI-H295R cells, which carry a constitutively active β-Catenin mutation.

CONCLUSIONS

The gene BCL9 is overexpressed in malignant adrenocortical tumors and promotes clonal ACC cell growth. These findings suggest that BCL9 overexpression may serve as an alternative driver of constitutive Wnt/β-Catenin activation in ACC and could represent a potential molecular and diagnostic marker of tumor malignancy.

Overexpression of cytochrome P450 2A6 in adrenocortical carcinoma

BACKGROUND

Cytochrome P450-mediated metabolism of chemotherapeutic agents contributes to chemotherapy resistance in multiple malignancies. Adrenocortical carcinoma is known to have a poor response to adjuvant therapies; however, the mechanism remains unknown. Recent comprehensive genetic analyses of adrenocortical carcinomas demonstrated recurrent copy number gains in multiple cytochrome P450 genes prompting investigation into whether cytochrome P450 overexpression potentiates adrenocortical carcinoma chemoresistance.

METHODS

We determined the expression patterns of 6 cytochrome P450 genes (CYP2A6, CYP2A7, CYP2A13, CYP2B6, CYP2S1, and CYP4F2) predicted to be amplified in adrenocortical carcinoma (n = 29) relative to normal adrenal cortex (n = 10). Gene copy numbers were determined with the TaqMan copy number assay. Gene silencing was performed via small interfering RNA (siRNA) in the adrenocortical carcinoma cell line NCI-H295R and treated with mitotane and cisplatin.

RESULTS

Of the 6 cytochrome P450 genes tested, CYP2A6 was overexpressed with a 55-fold mean increase compared to normal adrenal samples (P < .05). Immunohistochemical analysis confirmed protein overexpression. Copy gains of CYP2A6 were found in 26% (7/27) of adrenocortical carcinoma specimens. Silencing of CYP2A6 in NCI-H295R cells resulted in decreased cell viability and increased chemosensitivity (P < .05).

CONCLUSION

Frequent upregulation in adrenocortical carcinomas and the reversal of chemoresistance in adrenocortical carcinoma cells via enforced silencing suggest a role for CYP2A6 in adrenocortical malignancy.

Mutational Analysis of ZFY in Sporadic Parathyroid Adenomas

Context:

The molecular pathogenesis of sporadic parathyroid adenomas is incompletely understood, with alterations in cyclin D1/PRAD1 and MEN1 most firmly established as genetic drivers. The gene encoding the X-linked zinc finger protein (ZFX) has recently been implicated in the pathogenesis of a subset of parathyroid adenomas after recurrent, hotspot-focused somatic mutations were identified. ZFX escapes X inactivation and is transcribed from both alleles in women, and a highly homologous gene encoding the Y-linked zinc finger protein (ZFY) provides dosage compensation in males.

Objective:

We sought to investigate the role of ZFY mutation in sporadic parathyroid adenoma.

Intervention:

Polymerase chain reaction and Sanger sequencing were used to examine DNA from typically presenting, sporadic (nonfamilial, nonsyndromic) parathyroid adenomas from male patients for mutations within the ZFY gene.

Results:

No mutations were identified among 117 adenomas.

Conclusions:

The absence of ZFY mutations in this series suggests that ZFY rarely, if ever, acts as a driver oncogene in sporadic parathyroid adenomas. The apparent differences in tumorigenic capabilities between the closely related zinc finger proteins ZFX and ZFY suggest that structure-function studies could represent an opportunity to gain insight into neoplastic processes in the parathyroid glands.

A novel FOXO1-mediated dedifferentiation blocking role for DKK3 in adrenocortical carcinogenesis

Background

Dysregulated WNT signaling dominates adrenocortical malignancies. This study investigates whether silencing of the WNT negative regulator DKK3 (Dickkopf-related protein 3), an implicated adrenocortical differentiation marker and an established tumor suppressor in multiple cancers, allows dedifferentiation of the adrenal cortex.

Methods

We analyzed the expression and regulation of DKK3 in human adrenocortical carcinoma (ACC) by qRT-PCR, immunofluorescence, promoter methylation assay, and copy number analysis. We also conducted functional studies on ACC cell lines, NCI-H295R and SW-13, using siRNAs and enforced DKK3 expression to test DKK3’s role in blocking dedifferentiation of adrenal cortex.

Results

While robust expression was observed in normal adrenal cortex, DKK3 was down-regulated in the majority (>75%) of adrenocortical carcinomas (ACC) tested. Both genetic (gene copy loss) and epigenetic (promoter methylation) events were found to play significant roles in DKK3 down-regulation in ACCs. While NCI-H295R cells harboring β-catenin activating mutations failed to respond to DKK3 silencing, SW-13 cells showed increased motility and reduced clonal growth. Conversely, exogenously added DKK3 also increased motility of SW-13 cells without influencing their growth. Enforced over-expression of DKK3 in SW-13 cells resulted in slower cell growth by an extension of G1 phase, promoted survival of microcolonies, and resulted in significant impairment of migratory and invasive behaviors, largely attributable to modified cell adhesions and adhesion kinetics. DKK3-over-expressing cells also showed increased expression of Forkhead Box Protein O1 (FOXO1) transcription factor, RNAi silencing of which partially restored the migratory proficiency of cells without interfering with their viability.

Conclusions

DKK3 suppression observed in ACCs and the effects of manipulation of DKK3 expression in ACC cell lines suggest a FOXO1-mediated differentiation-promoting role for DKK3 in the adrenal cortex, silencing of which may allow adrenocortical dedifferentiation and malignancy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3152-5) contains supplementary material, which is available to authorized users.

Novel somatic mutations in primary hyperaldosteronism are related to the clinical, radiological and pathological phenotype

Aldosterone-producing adenomas (APAs) and bilateral adrenal hyperplasia are important causes of secondary hypertension. Somatic mutations in KCNJ5, CACNA1D, ATP1A1, ATP2B3 and CTNNB1 have been described in APAs.

OBJECTIVE

To characterize clinical-pathological features in APAs and unilateral adrenal hyperplasia, and correlate them with genotypes.

DESIGN

Retrospective study.

SUBJECTS AND MEASUREMENTS

Clinical and pathological characteristics of 90 APAs and seven diffusely or focally hyperplastic adrenal glands were reviewed, and samples were examined for mutations in known disease genes by Sanger or exome sequencing.

RESULTS

Mutation frequencies were as follows: KCNJ5, 37·1%; CACNA1D, 10·3%; ATP1A1, 8·2%; ATP2B3, 3·1%; and CTNNB1, 2·1%. Previously unidentified mutations included I157K, F154C and two insertions (I150_G151insM and I144_E145insAI) in KCNJ5, all close to the selectivity filter, V426G_V427Q_A428_L433del in ATP2B3 and A39Efs*3 in CTNNB1. Mutations in KCNJ5 were associated with female and other mutations with male gender (P = 0·007). On computed tomography, KCNJ5-mutant tumours displayed significantly greater diameter (P = 0·023), calculated area (P = 0·002) and lower precontrast Hounsfield units (P = 0·0002) vs tumours with mutations in other genes. Accordingly, KCNJ5-mutant tumours were predominantly comprised of lipid-rich fasciculata-like clear cells, whereas other tumours were heterogeneous (P = 5 × 10(-6) vs non-KCNJ5 mutant and P = 0·0003 vs wild-type tumours, respectively). CACNA1D mutations were present in two samples with hyperplasia without adenoma.

CONCLUSIONS

KCNJ5-mutant tumours appear to be associated with fasciculata-like clear cell predominant histology and tend to be larger with a characteristic imaging phenotype. Novel somatic KCNJ5 variants likely cause adenomas by loss of potassium selectivity, similar to previously described mutations.

DNA copy amplification and overexpression of SLC12A7 in adrenocortical carcinoma

BACKGROUND

Overexpression of Solute carrier family 12 member 7 (SLC12A7) promotes tumor aggressiveness in various cancers. Previous studies have identified the 5p15.33 region, containing the SLC12A7 locus, as being amplified frequently in adrenocortical carcinoma (ACC). Copy number amplifications (CNAs) may alter gene expression levels and occur frequently in ACC; however, SLC12A7 gene amplifications or expression levels have not been studied in ACC.

METHODS

Fifty-five cases of clinically well-characterized ACCs were recruited for this study. Whole-exome sequencing was used to predict CNAs in 19 samples. CNA analysis was performed on an expanded cohort of 26 samples with the use of TaqMan Copy Number Assays. SLC12A7 mRNA expression was analyzed in 32 samples with real-time quantitative polymerase chain reaction and protein expression was assessed by immunohistochemistry. SLC12A7 CNAs and expression patterns were evaluated for correlation with patient and tumor characteristics.

RESULTS

Whole-exome sequencing and TaqMan Copy Number Assays demonstrated SLC12A7 amplifications in 68.4% and 65.4% of ACCs tested, respectively. Furthermore, SLC12A7 copy gains were associated with increased gene expression (P < .05) and non-functional tumors (P < .05). SLC12A7 gene expression levels were increased in ACCs compared with normal adrenal tissue (P < .05).

CONCLUSION

SLC12A7 gene amplification and overexpression occurs frequently in ACCs and may represent a novel molecular event associated with ACC.

Chromosome 19 amplification correlates with advanced disease in adrenocortical carcinoma

BACKGROUND

Familial syndromes with specific genetic drivers account for a subset of adrenocortical carcinomas (ACCs), but the genomic underpinnings of sporadic cases remain poorly understood. Recent advances in copy number variation (CNV) prediction from exome sequencing are facilitating exploration of genomic rearrangements common to these carcinomas.

METHODS

ACC and matched, nontumor samples underwent exome sequencing. CNVs were predicted using coverage-depth comparison. Clinicopathologic characteristics of amplification- and deletion-dominant samples were compared and pathway enrichment analysis performed for regions with significant variation.

RESULTS

CNVs are distributed broadly across the ACC genome. Individual signatures demonstrate amplification or deletion dominance. Areas of recurrent amplification include chromosomes 5, 12, 19, and 20, whereas chromosomes 1, 10, 18, and 22 are deletion prone. Large-scale amplification of chromosome 19 occurred in 12 of 19 cases (63%), including 6 of 8 amplification-dominant samples (75%) and was associated with stage III/IV disease (P = .002). Genes within this amplified region are overrepresented among the adrenal hyperplasia and steroid biosynthesis pathways (P = 4.2(-5) and 2.5(-5), respectively).

CONCLUSION

CNV detection via exome sequencing allows high-resolution cataloging of structural variations in ACC. Large-scale, recurrent amplifications encompassing known adrenal-specific gene pathways correlate with tumor stage. Further functional analysis of individual genes within these regions could provide mechanistic insight into specific drivers underlying pathogenesis and progression of ACC.

Case Report-Loyalty, Legacy, and Ledger: Contextual Therapy in a Patient with a Family History of Ovarian Cancer

A client's emotional experiences and reactions to those experiences are influenced by his/her family of origin and direct or indirect interactions with various family members. Contextual therapists propose that a client's satisfaction with a relationship depends on the equity of his/her emotional interactions with family members. When relationships are inequitable, trust between individuals disintegrates. In order to reestablish trust in a relationship, a balance of interests must be restored. If not, imbalances may be passed down to future generations. A case of a woman with a family history of ovarian cancer is reviewed with the principles of contextual therapy in mind. In her family, several legacies have resulted in unbalanced relationships between family members that lead to difficulty in establishing trust within the genetic counseling session.

Whole-exome sequencing defines the mutational landscape of pheochromocytoma and identifies KMT2D as a recurrently mutated gene

As subsets of pheochromocytomas (PCCs) lack a defined molecular etiology, we sought to characterize the mutational landscape of PCCs to identify novel gene candidates involved in disease development. A discovery cohort of 15 PCCs wild type for mutations in PCC susceptibility genes underwent whole‐exome sequencing, and an additional 83 PCCs served as a verification cohort for targeted sequencing of candidate mutations. A low rate of nonsilent single nucleotide variants (SNVs) was detected (6.1/sample). Somatic HRAS and EPAS1 mutations were observed in one case each, whereas the remaining 13 cases did not exhibit variants in established PCC genes. SNVs aggregated in apoptosis‐related pathways, and mutations in COSMIC genes not previously reported in PCCs included ZAN, MITF, WDTC1, and CAMTA1. Two somatic mutations and one constitutional variant in the well‐established cancer gene lysine (K)‐specific methyltransferase 2D (KMT2D, MLL2) were discovered in one sample each, prompting KMT2D screening using focused exome‐sequencing in the verification cohort. An additional 11 PCCs displayed KMT2D variants, of which two were recurrent. In total, missense KMT2D variants were found in 14 (11 somatic, two constitutional, one undetermined) of 99 PCCs (14%). Five cases displayed somatic mutations in the functional FYR/SET domains of KMT2D, constituting 36% of all KMT2D‐mutated PCCs. KMT2D expression was upregulated in PCCs compared to normal adrenals, and KMT2D overexpression positively affected cell migration in a PCC cell line. We conclude that KMT2D represents a recurrently mutated gene with potential implication for PCC development. © 2015 The Authors. Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc.

Characterization of the mutational landscape of anaplastic thyroid cancer via whole-exome sequencing

Anaplastic thyroid carcinoma (ATC) is a frequently lethal malignancy that is often unresponsive to available therapeutic strategies. The tumorigenesis of ATC and its relationship to the widely prevalent well-differentiated thyroid carcinomas are unclear. We have analyzed 22 cases of ATC as well as 4 established ATC cell lines using whole-exome sequencing. A total of 2674 somatic mutations (121/sample) were detected. Ontology analysis revealed that the majority of variants aggregated in the MAPK, ErbB and RAS signaling pathways. Mutations in genes related to malignancy not previously associated with thyroid tumorigenesis were observed, including mTOR, NF1, NF2, MLH1, MLH3, MSH5, MSH6, ERBB2, EIF1AX and USH2A; some of which were recurrent and were investigated in 24 additional ATC cases and 8 ATC cell lines. Somatic mutations in established thyroid cancer genes were detected in 14 of 22 (64%) tumors and included recurrent mutations in BRAF, TP53 and RAS-family genes (6 cases each), as well as PIK3CA (2 cases) and single cases of CDKN1B, CDKN2C, CTNNB1 and RET mutations. BRAF V600E and RAS mutations were mutually exclusive; all ATC cell lines exhibited a combination of mutations in either BRAF and TP53 or NRAS and TP53. A hypermutator phenotype in two cases with >8 times higher mutational burden than the remaining mean was identified; both cases harbored unique somatic mutations in MLH mismatch-repair genes. This first comprehensive exome-wide analysis of the mutational landscape of ATC identifies novel genes potentially associated with ATC tumorigenesis, some of which may be targets for future therapeutic intervention.

Frequent silencing of RASSF1A via promoter methylation in follicular thyroid hyperplasia: a potential early epigenetic susceptibility event in thyroid carcinogenesis

IMPORTANCE

Follicular thyroid hyperplasia (FTH) refers to enlargement of the thyroid gland due to cellular hyperplasia. It is frequently encountered in clinical practice in nontoxic uninodular or multinodular goiter. The genetic and epigenetic events associated with the origin and malignant potential of FTH are poorly understood.

OBJECTIVE

To analyze FTH samples for known recurrent genetic and epigenetic driver events in thyroid neoplasms such as activating mutations in proto-oncogenes BRAF and NRAS and promoter hypermethylation of tumor suppressor genes CDKN2A, PTEN, and RASSF1A.

DESIGN, SETTING, AND PARTICIPANTS

Clinical characteristics and thyroid specimens were prospectively obtained from 43 patients who underwent thyroid surgery at Yale-New Haven Hospital.

MAIN OUTCOMES AND MEASURES

Presence of BRAF(V600E) and NRAS codon 61 mutations were assessed in FTH. Methylation status of CDKN2A, PTEN, and RASSF1A gene promoters in FTH, follicular thyroid adenoma, and follicular thyroid carcinoma was quantified. Regulation of RASSF1A messenger RNA (mRNA) and protein expression and its potential neoplastic role in FTH were examined.

RESULTS

An exploratory cohort of FTH (n = 10) was negative for BRAF(V600E) and NRAS codon 61 mutations. In contrast, epigenetic analysis displayed significant promoter hypermethylation of the tumor-suppressor gene RASSF1A in 6 FTH samples (60%) compared with their adjacent normal tissue (P = .01). The overall genome CpG methylation and promoter methylation of PTEN and CDKN2A were unaffected in the lesions. Further analysis of an expanded cohort of patients with FTH (n = 23), follicular thyroid adenoma (n = 10), and follicular thyroid carcinoma (n = 10) showed RASSF1A promoter hypermethylation in 14 (61%), 9 (90%), and 7 (70%), respectively (P < .001). The overall hypermethylation level in FTH showed a statistically significant inverse correlation with RASSF1A mRNA expression (P = .005). Immunohistochemistry demonstrated minimal or no protein expression in most FTH samples studied. To explore the potential neoplastic contribution of RASSF1A downregulation, we analyzed the expression pattern of thyroid proliferation markers Ki-67 and NF-κB in representative samples. Although Ki-67 expression was undetectable, similar to normal tissue, FTH samples expressed high levels of NF-κB, similar to the expression levels in thyroid tumors.

CONCLUSIONS AND RELEVANCE

We demonstrate silencing of tumor suppressor RASSF1A in a subset of FTH in the absence of other known thyroid cancer-associated genetic and epigenetic changes. Silencing of RASSF1A and concurrent NF-κB activation demonstrate that a subset of FTH shares epigenetic changes and downstream signaling events associated with malignant lesions, suggesting that FTH may have the potential to be a premalignant lesion.

Whole-exome sequencing characterizes the landscape of somatic mutations and copy number alterations in adrenocortical carcinoma

CONTEXT

Adrenocortical carcinoma (ACC) is a rare and lethal malignancy with a poorly defined etiology, and the molecular genetics of ACC are incompletely understood.

OBJECTIVE

To utilize whole-exome sequencing for genetic characterization of the underlying somatic mutations and copy number alterations present in ACC.

DESIGN

Screening for somatic mutation events and copy number alterations (CNAs) was performed by comparative analysis of tumors and matched normal samples from 41 patients with ACC.

RESULTS

In total, 966 nonsynonymous somatic mutations were detected, including 40 tumors with a mean of 16 mutations per sample and one tumor with 314 mutations. Somatic mutations in ACC-associated genes included TP53 (8/41 tumors, 19.5%) and CTNNB1 (4/41, 9.8%). Genes with potential disease-causing mutations included GNAS, NF2, and RB1, and recurrently mutated genes with unknown roles in tumorigenesis comprised CDC27, SCN7A, and SDK1. Recurrent CNAs included amplification at 5p15.33 including TERT (6/41, 14.6%) and homozygous deletion at 22q12.1 including the Wnt repressors ZNRF3 and KREMEN1 (4/41 9.8% and 3/41, 7.3%, respectively). Somatic mutations in ACC-established genes and recurrent ZNRF3 and TERT loci CNAs were mutually exclusive in the majority of cases. Moreover, gene ontology identified Wnt signaling as the most frequently mutated pathway in ACCs.

CONCLUSIONS

These findings highlight the importance of Wnt pathway dysregulation in ACC and corroborate the finding of homozygous deletion of Wnt repressors ZNRF3 and KREMEN1. Overall, mutations in either TP53 or CTNNB1 as well as focal CNAs at the ZNRF3 or TERT loci denote mutually exclusive events, suggesting separate mechanisms underlying the development of these tumors.

Heart block and acute kidney injury due to hyperparathyroidism-induced hypercalcemic crisis

We describe a patient who presented with multi-system organ failure due to extreme hypercalcemia (serum calcium 19.8 mg/dL), resulting from primary hyperparathyroidism. He was found to have a 4.8 cm solitary atypical parathyroid adenoma. His course was complicated by complete heart block, acute kidney injury, and significant neurocognitive disturbances. Relevant literature was reviewed and discussed. Hyperparathyroidism-induced hypercalcemic crisis (HIHC) is a rare presentation of primary hyperparathyroidism and only a small minority of these patients develop significant cardiac and renal complications. In cases of HIHC, a multidisciplinary effort can facilitate rapid treatment of life-threatening hypercalcemia and definitive treatment by surgical resection. As such, temporary transvenous cardiac pacing and renal replacement therapy can provide a life-saving bridge to definitive parathyroidectomy in cases of HIHC.

Modern experience with aggressive parathyroid tumors in a high-volume New England referral center

BACKGROUND

Parathyroid carcinoma (PTCA) is an exceptionally rare malignancy, often with a clinical presentation similar to that of benign atypical parathyroid adenoma. Its low incidence portends unclear guidelines for management. Accordingly, thorough examination of clinical and pathologic variables was undertaken to distinguish between PTCA and atypical adenomas.

STUDY DESIGN

This was a retrospective analysis of a prospective database at a tertiary academic referral center. Between September 2001 and April 2014, 3,643 patients were referred for surgical treatment of PHPT. Of these, 52 harbored aggressive parathyroid tumors: parathyroid carcinomas (n=18) and atypical adenomas (n=34). We analyzed the surgical and clinicopathologic tumor characteristics, and did a statistical analysis. We measured preoperative and intraoperative variables, and postoperative and pathologic outcomes.

RESULTS

Parathyroid carcinoma patients present with significantly increased tumor size (3.5 cm vs 2.4 cm, respectively; p=0.002), mean serum calcium (13.0 vs 11.8 mg/dL, respectively; p=0.003) and intact parathyroid hormone (iPTH) levels (489 vs 266 pg/mL, respectively; p=0.04), and a higher incidence of hypercalcemic crisis, compared with patients with atypical adenomas (50% vs 19%, respectively; p=0.072). Parathyroid carcinoma more frequently lacks a distinct capsule (47.1% vs 12.9%, respectively; p=0.03) and adheres to adjacent structures (77.8% vs 20.6%, respectively; p=0.017). Of note, there was no significant difference in loss of parafibromin expression between groups.

CONCLUSIONS

Clinical distinction between PTCA and atypical adenomas is of critical importance in determining the appropriate extent of resection and follow-up. Loss of parafibromin has not been shown to distinguish between PTCA and atypical adenoma; clearer definition of clinicopathologic criteria for PTCA is warranted and may lead to improved postoperative management.

The activating TERT promoter mutation C228T is recurrent in subsets of adrenal tumors

The telomerase reverse transcriptase gene (TERT) encodes the reverse transcriptase component of the telomerase complex, which is essential for telomere stabilization and cell immortalization. Recent studies have demonstrated a transcriptional activation role for the TERT promoter mutations C228T and C250T in many human cancers, as well as a role in aggressive disease with potential clinical applications. Although telomerase activation is known in adrenal tumors, the underlying mechanisms are not established. We assessed C228T and C250T TERT mutations by direct Sanger sequencing in tumors of the adrenal gland, and further evaluated potential associations with clinical parameters and telomerase activation. A total of 199 tumors were evaluated, including 34 adrenocortical carcinomas (ACC), 47 adrenocortical adenomas (ACA), 105 pheochromocytomas (PCC; ten malignant and 95 benign), and 13 abdominal paragangliomas (PGL; nine malignant and four benign). TERT expression levels were determined by quantitative RT-PCR. The C228T mutation was detected in 4/34 ACCs (12%), but not in any ACA (P=0.028). C228T was also observed in one benign PCC and in one metastatic PGL. The C250T mutation was not observed in any case. In the ACC and PGL groups, TERT mutation-positive cases exhibited TERT expression, indicating telomerase activation; however, since expression was also revealed in TERT WT cases, this could denote additional mechanisms of TERT activation. To conclude, the TERT promoter mutation C228T is a recurrent event associated with TERT expression in ACCs, but rarely occurs in PGL and PCC. The involvement of the TERT gene in ACC represents a novel mutated gene in this entity.

Expression level dependent changes in the properties of P2X2 receptors

The currents of P2X(2) receptors expressed in Xenopus oocytes or HEK293 cells show significant cell-to-cell variation in many properties including the rate of desensitization and the magnitude of potentiation by zinc or acidic pH. In this study, we examined whether differences in expression levels underlie this variability. We injected Xenopus oocytes with different concentrations of RNA encoding rat P2X(2) to give a wide range of maximum current amplitudes, and then measured the potentiation of responses to 10 micro M adenosine 5'-triphosphate (ATP) by zinc or acidic pH. Individual oocytes showed potentiation ratios that ranged from 1.4- to 25-fold. Oocytes with small amplitude responses to a saturating concentration of ATP tended to have larger potentiation ratios than oocytes with large amplitude responses. This phenomenon was explained by an inverse correlation between the EC(50) for ATP and the maximum current amplitude, with the EC(50) decreasing from about 37 to 7 micro M as expression level increased. In contrast, the Hill coefficient was not correlated with the maximum current amplitude. Truncated receptors lacking the last 76 amino acids also showed an inverse correlation between the EC(50) and the maximum current amplitude. Thus, the interactions that cause expression-dependent changes in P2X(2) receptor properties must involve domains proximal to position H397.

Effects of the laryngeal mask airway on the lower oesophageal barrier pressure in children

The effects of laryngeal mask airway (LMA) insertion and cuff inflation on lower oesophageal sphincter, gastric and barrier pressure, and the relationship of the LMA cuff pressure and volume on the change in the barrier pressure were studied in 20 children. Subjects were aged one to five years, undergoing eye examination under general anaesthesia. There was no significant change in barrier pressure after insertion and inflation of the LMA compared with baseline measures. The cuff pressure and volume were not related to the change in barrier pressure. Two patients had marked decreases (10 to 15 mmHg) in barrier pressure after the LMA insertion. These decreases in barrier pressure would be expected to increase the risk of gastro-oesophageal reflux. We conclude that, although LMA use had little effect on barrier pressure in most children, occasional children will have potentially clinically significant decreases in barrier pressure with use of the LMA.

Anaesthesia and pain management in cerebral palsy

Cerebral palsy is the result of an injury to the developing brain during the antenatal, perinatal or postnatal period. Clinical manifestations relate to the area affected. Some of the conditions associated with cerebral palsy require surgical intervention. Problems during the peri-operative period may include hypothermia, nausea and vomiting and muscle spasm. Peri-operative seizure control, respiratory function and gastro-oesophageal reflux also require consideration. Intellectual disability is common and, in those affected, may range from mild to severe. These children should be handled with sensitivity as communication disorders and sensory deficits may mask mild or normal intellect. They should be accompanied by their carers at induction and in the recovery room as they usually know how best to communicate with them. Postoperative pain management and the prevention of muscle spasm is important and some of the drugs used in the management of spasm such as baclofen and botulinum toxin are discussed. Epidural analgesia is particularly valuable when major orthopaedic procedures are performed.

The etiology of intestinal obstruction in patients without prior laparotomy or hernia

Patients with clinical features of intestinal obstruction without a history of prior laparotomy or physical evidence of a hernia can be a diagnostic challenge. We attempted to evaluate our preoperative diagnostic accuracy, to assess the effectiveness of our diagnostic tools, and to determine the incidence of various causes of intestinal obstruction in this select group. Medical records of all patients admitted to our institution and taken to surgery with a diagnosis of intestinal obstruction from 1975 through 1995 were reviewed. Patients with a history of prior laparotomy, evidence of hernia, or emergent indications for surgery on admission were excluded. The most common cause of intestinal obstruction in this select group of patients was malignancy. The ability to detect malignancy preoperatively is significantly better than the ability to detect benign causes of obstruction (Pearson Chi square = 4.09 with a P value of 0.04). Preoperative detection of malignancy in these patients is critical for optimal treatment planning and counseling for patients and their families.

Instability of the FMR2 trinucleotide repeat region associated with expanded FMR1 alleles

The fragile sites FRAXA and FRAXE, located approximately 600 kb apart on Xq27.3 and Xq28, respectively, are due to a CGG trinucleotide repeat expansion. Although the expansion mechanism for these and other trinucleotide repeat disorders remains unknown, the similarities between the FRAXA and FRAXE regions suggest a possible association between the 2 sites. DNA from 953 individuals was analyzed to determine the distribution of FRAXE repeat sizes in this population and to ascertain potential association between FRAXA and FRAXE repeat sizes. Thirty-four FMR2 alleles ranging from 3-42 repeats were identified. No FRAXE expansions were found in this population, supporting previous findings that FRAXE expansions are rare. However, in the fragile X syndrome affected group, a FMR2 delection, 2 cases of FRAXE repeat instability and a FRAXE mosaic male were identified. Also, a previously identified, rare FMR2 polymorphism was observed. Statistical analysis showed no correlation between normal FRAXA and FRAXE repeat sizes studied, although there was a significant size difference in larger FMR2 alleles that segregated with expanded FMR1 alleles. These findings support the idea of an association between repeat expansion in the FMR1 gene and instability or deletions in the FMR2 gene.

Paediatric tracheobronchomalacia and its assessment by tracheobronchography

Tracheobronchomalacia (TBM) is a rare condition that results in abnormal compliance of the airways with airway collapse being most marked in expiration. In a series of 28 patients, it was observed that a majority of cases presented with malacia involving the trachea (64%) and the left main bronchus (64%) alone. The right main bronchus was involved in combination with the trachea in 32%, but rarely was involved by itself. Most patients demonstrated associated congenital abnormalities, such as tracheo-oesophageal fistulae, vascular rings or congenital heart disease (78%). A small proportion were premature infants with no obvious associated abnormality (11%). Evaluation of the dynamic process, tracheobronchomalacia; requires 'real-time' investigation. While computed tomography (CT) and magnetic resonance imaging (MRI) have their role in the management of chronic airway obstruction in the child, only cine-CT, bronchoscopy, fluoroscopy and tracheobronchography provide real-time assessment for the evaluation of a dynamic process such as TBM. In our experience, tracheobronchography provides excellent anatomic, physiologic and therapeutic information in the assessment of those infants with primary or secondary TBM. By using continuous positive airway pressure in incremental doses, the amount of positive pressure required to maintain an open airway in expiration is a valuable adjunct to the clinical management of the patient. When careful attention is paid to technique, tracheobronchography is a safe investigation in experienced hands.

Anaesthesia for children with mucopolysaccharidoses

The mucopolysaccharidoses are a group of inherited disorders of metabolism, with varying clinical manifestations. A number of them present anaesthetic difficulties. This paper presents a summary table of the syndromes and reviews our experience over ten years with patients with these diagnoses. The clinical presentations, anaesthetic management, and complications are described. The effect of age and diagnosis on airway difficulties was studied. There were 31 patients, 28 of whom required anaesthesia, on a total of 99 occasions, for 115 procedures. The patients with Hunter, Hurler and Maroteaux-Lamy syndromes had significantly more airway difficulties as they grew older, and compared with patients in this group with other syndromes. Patients with Hurler's syndrome may have coronary artery involvement and one patient was given fentanyl and pancuronium for this reason. He proved impossible to intubate and an emergency tracheostomy was performed.

Reduction of bowel motion artifact during digital subtraction angiography: a comparison of hyoscine butylbromide and glucagon

The authors compared the effectiveness of hyoscine butylbromide (Buscopan) and glucagon in reducing bowel motion artifact during abdominal intra-arterial digital subtraction angiography. Sixty-six patients referred to the radiology department of a tertiary-care hospital for abdominal angiography between October 1989 and July 1992 consented to participate in the study. Diabetic patients receiving insulin and those with glaucoma were not considered for the study. The patients were assigned at random to receive either Buscopan (39 patients) or glucagon (27) intravenously before angiography. Images obtained at three stages during the procedure were reviewed independently by three experienced vascular radiologists who were blinded as to treatment group; images for nine patients in the Buscopan group and seven in the glucagon group were excluded because of breathing artifact or body movement. For each image the radiologists scored bowel motion in each section of a six-section grid. The bowel motion scores during early, middle and late arterial phases and the total scores for the two groups did not differ significantly (t-test). On the basis of these findings, the authors continue to use Buscopan because it is less expensive than glucagon.

Evaluation of cutaneous photodamage using a photographic scale

Clinical assessments of photodamage are based upon a subjective evaluation of characteristic features such as wrinkling and pigmentary change, and are influenced by inter-observer differences in grading criteria. In an effort to standardize the grading of photodamage severity, we have developed a six-point photographic scale in which each of the six grades of overall photodamage severity is depicted by three photographs. The use of three photographs to portray each grade illustrates the diversity and range of manifestations within each grade. This photographic scale was tested by two groups of dermatologists, who used it on two occasions to grade the overall photodamage severity of a single group of female Caucasian subjects. Results indicate high inter-observer agreement, with chance-corrected agreement ranging from 0.44 to 0.63 and from 0.54 to 0.76 on the first and second occasions, respectively. Intra-observer repeatability was high, with chance-corrected agreement ranging from 0.56 to 0.78. Inter- and intra-observer differences were within one category in nearly all cases. Similar grades were assigned by dermatologists with and without experience in treating photodamaged patients. We conclude that application of this scale results in consistent and reproducible clinical evaluations of overall photodamage severity in Caucasian subjects. The scale may be useful in categorizing subjects for epidemiological studies, or in selecting patients for clinical trials.

Pseudoaneurysm of the inferior gluteal artery

Aneurysms of the inferior gluteal artery are uncommon, and have not previously been described in detail in the radiologic literature. The authors report the findings of computed tomography and angiography for a patient with a pseudoaneurysm of the inferior gluteal artery who was successfully treated by embolization alone.

Pneumothorax secondary to foreign body inhalation in a 20 month old child

A 20 month old child presented with acute onset of respiratory embarrassment as a result of a left-sided tension pneumothorax. This proved to be caused by inhalation of an unusual foreign body: the hair from a rag doll.

Financial analysis of a family practice residency threatened with closure

Family practice residency programs often find themselves needing to fiscally justify their existence to their sponsoring institutions. One such program in a community hospital was threatened with closure, to be replaced by salaried and/or fee-for-service physicians. We present an applied research methodology for comparing the residency budget and revenues with that of a replacement delivery system with no educational mission. The total expenses for nonresidency physicians were projected to be from 10.5% to 25.1% less than the residency budget. Revenues generated by nonresidency physicians were projected to be from 29.4% to 37.6% less than those of the residency, primarily due to the loss of grants and graduate medical education reimbursement through the Medicare program. Proposed reductions in grants and graduate medical education reimbursement threaten the budget/revenue balance of this and other family practice residency programs.