MicroRNA-7 as a tumor suppressor and novel therapeutic for adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) has a poor prognosis with significant unmet clinical need due to late diagnosis, high rates of recurrence/metastasis and poor response to conventional treatment. Replacing tumor suppressor microRNAs (miRNAs) offer a novel therapy, however systemic delivery remains challenging. A number of miRNAs have been described to be under-expressed in ACC however it is not known if they form a part of ACC pathogenesis. Here we report that microRNA-7-5p (miR-7) reduces cell proliferation in vitro and induces G1 cell cycle arrest. Systemic miR-7 administration in a targeted, clinically safe delivery vesicle (EGFREDVTM nanocells) reduces ACC xenograft growth originating from both ACC cell lines and primary ACC cells. Mechanistically, miR-7 targets Raf-1 proto-oncogene serine/threonine kinase (RAF1) and mechanistic target of rapamycin (MTOR). Additionally, miR-7 therapy in vivo leads to inhibition of cyclin dependent kinase 1 (CDK1). In patient ACC samples, CDK1 is overexpressed and miR-7 expression inversely related. In summary, miR-7 inhibits multiple oncogenic pathways and reduces ACC growth when systemically delivered using EDVTM nanoparticles. This data is the first study in ACC investigating the possibility of miRNAs replacement as a novel therapy.

Current management options for recurrent adrenocortical carcinoma.

Adrenal cortical carcinoma (ACC) is a rare cancer that poses a number of management challenges due to the limited number of effective systemic treatments. Complete surgical resection offers the best chance of long-term survival. However, despite complete resection, ACC is associated with high recurrence rates. This review will discuss the management of recurrent ACC in adults following complete surgical resection. Management should take place in a specialist center and treatment decisions must consider the individual tumor biology of each case of recurrence. Given the fact that ACC commonly recurs, management to prevent recurrence should be considered from initial diagnosis with the use of adjuvant mitotane. Close follow up with clinical examination and imaging is important for early detection of recurrent disease. Locoregional recurrence may be isolated, and repeat surgical resection should be considered along with mitotane. The use of radiotherapy in ACC remains controversial. Systemic recurrence most often involves liver, pulmonary, and bone metastasis and is usually managed with mitotane, with or without combination chemotherapy. There is a limited role for surgical resection in systemic recurrence in selected patients. In all patients with recurrent disease, control of excessive hormone production is an important part of management. Despite intensive management of recurrent ACC, treatment failure is common and the use of clinical trials and novel treatment is an important part of management.

Breast cancer-associated fibroblasts induce epithelial-to-mesenchymal transition in breast cancer cells.

Cancer-associated fibroblasts (CAFs) play a role in tumour initiation and progression, possibly by inducing epithelial-to-mesenchymal transition (EMT), a series of cellular changes that is known to underlie the process of metastasis. The aim of this study was to determine whether CAFs and surrounding normal breast fibroblasts (NBFs) are able to induce EMT markers and functional changes in breast epithelial cancer cells. Matched pairs of CAFs and NBFs were established from fresh human breast cancer specimens and characterised by assessment of CXCL12 levels, α-smooth muscle actin (α-SMA) levels and response to doxorubicin. The fibroblasts were then co-cultured with MCF7 cells. Vimentin and E-cadherin expressions were determined in co-cultured MCF7 cells by immunofluorescence and confocal microscopy as well as by western blotting and quantitative PCR. Co-cultured MCF7 cells were also assessed functionally by invasion assay. CAFs secreted higher levels of CXCL12 and expressed higher levels of α-SMA compared with NBFs. CAFs were also less sensitive to doxorubicin as evidenced by less H2AX phosphorylation and reduced apoptosis on flow cytometric analysis of Annexin V compared with NBFs. When co-cultured with MCF7 cells, there was greater vimentin and less E-cadherin expression as well as greater invasiveness in MCF7 cells co-cultured with CAFs compared with those co-cultured with NBFs. CAFs have the ability to induce a greater degree of EMT in MCF7 cell lines, indicating that CAFs contribute to a more malignant breast cancer phenotype and their role in influencing therapy resistance should therefore be considered when treating breast cancer.

Dysregulation of microRNAs in adrenocortical tumors.

MicroRNAs (miRNAs) are short non-coding RNAs that are involved in the epigenetic regulation of cellular processes. Different malignancies are often associated with the deregulation of specific sets of miRNAs. The prognosis of adrenocortical cancers (ACCs) is very poor as compared to adrenocortical adenomas (ACAs), and even within ACCs there are cases with better disease specific survival. An improved understanding of the pathobiology of this disease will therefore be useful in facilitating better management of ACCs as well as distinguishing high risk versus low risk subgroups. One third of coding genes are regulated by miRNAs and therefore changes in miRNA expression may be associated with cancer development and progression. In this review we summarize the current understanding of miRNAs in adrenocortical tumors, and highlight their potential in differentiating between ACCs and ACAs, risk stratification and prognosis.

Current and emerging therapies for advanced adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare but aggressive malignancy with a poor prognosis. Complete surgical resection offers the only potential for cure; however, even after apparently successful excision, local or metastatic recurrence is frequent. Treatment options for advanced ACC are severely limited. Mitotane is the only recognized adrenolytic therapy available; however, response rates are modest and unpredictable whereas systemic toxicities are significant. Reported responses to conventional cytotoxic chemotherapy have also been disappointing, and the rarity of ACC had hampered the ability to undertake randomized clinical studies until the establishment of the First International Randomized Trial in Locally Advanced and Metastatic Adrenocortical Carcinoma. This yet-to-be reported study seeks to identify the most effective first- and second-line cytotoxic regimens. The past decade has also seen increasing research into the molecular pathogenesis of ACCs, with particular interest in the insulin-like growth factor signaling pathway. The widespread development of small molecule tyrosine kinase inhibitors in broader oncological practice is now allowing for the rational selection of targeted therapies to study in ACC. In this review, we discuss the currently available therapeutic options for patients with advanced ACC and detail the molecular rationale behind, and clinical evidence for, novel and emerging therapies.

Outcomes of minimally invasive surgery for phaeochromocytoma.

Laparoscopic adrenalectomy is now accepted as the procedure of choice for the resection of benign adrenocortical tumours, but few studies have assessed whether the outcomes of laparoscopic adrenalectomy for adrenal phaeochromocytoma are similar to that of other adrenal tumour types. This is a retrospective cohort study. Clinical and operative data were obtained from an adrenal tumour database and hospital records. A total of 191 patients had laparoscopic adrenalectomy, of which 36 were for phaeochromocytoma, over a 12-year period. Length of hospital stay (4.8 vs 3.6 days, P= 0.03) and total operating times (183 vs 157 min, P= 0.01) were greater in the laparoscopic phaeochromocytoma resection group. Despite the greater size of the phaeochromocytomas compared to the remaining adrenal tumour types (44 mm vs 30 mm, P < 0.01), however, rate of conversion and morbidity were no different. Laparoscopic adrenalectomy for phaeochromocytoma is a safe procedure with similar outcomes to laparoscopic adrenalectomy for other adrenal tumour types.

Molecular markers and the pathogenesis of adrenocortical cancer.

Adrenal tumors are common, with an estimated incidence of 7.3% in autopsy cases, while adrenocortical carcinomas (ACCs) are rare, with an estimated prevalence of 4-12 per million population. Because the prognoses for adrenocortical adenomas (ACAs) and ACCs are vastly different, it is important to be able to accurately differentiate the two tumor types. Advancement in the understanding of the pathophysiology of ACCs is essential for the development of more sensitive means of diagnosis and treatment, resulting in better clinical outcome. Adrenocortical tumors (ACTs) occur as a component of several hereditary tumor syndromes, which include the Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, multiple endocrine neoplasia 1, Carney complex, and congenital adrenal hyperplasia. The genes involved in these syndromes have also been shown to play a role in the pathogenesis of sporadic ACTs. The adrenocorticotropic hormone-cAMP-protein kinase A and Wnt pathways are also implicated in adrenocortical tumorigenesis. The aim of this review is to summarize the current knowledge on the molecular mechanisms involved in adrenocortical tumorigenesis, including results of comparative genomic hybridization, loss of heterozygosity, and microarray gene-expression profiling studies.

Surgeon performed ultrasound facilitates minimally invasive parathyroidectomy by the focused lateral mini-incision approach.

BACKGROUND: Minimally invasive parathyroidectomy (MIP) is now widely accepted where a single adenoma can be localized preoperatively. In our unit, MIP is offered once a parathyroid adenoma is localized with a sestamibi (MIBI) scan, with or without a concordant neck ultrasound. The aim of this study was to compare the accuracy of surgeon performed ultrasound (SUS) with radiologist performed ultrasound (RUS) in the localization of a parathyroid adenoma in MIBI-positive primary hyperparathyroidism (PHPT). PATIENTS AND METHODS: This is a prospective study of patients undergoing parathyroidectomy for sporadic primary hyperparathyroidism (PHPT) from April 2005 to October 2006 at the University of Sydney Endocrine Surgical Unit. Patients were then divided into those who underwent preoperative RUS or SUS. RESULTS: Two-hundred eighteen patients formed the study group. One hundred forty-eight (66%) patients had RUS and 87 (39%) had SUS. Overall, RUS correctly localized the parathyroid adenomas in 121 of 148 (82%) patients. Surgeon performed ultrasound correctly localized the abnormal parathyroid adenoma in 72 of 87 (83%) of cases. There was no significant difference in the proportion of patients with single gland disease, double adenomas, or hyperplasia correctly localized by SUS or RUS. Incorrect interpretation of ultrasound imaging was due to cystic degeneration in thyroid nodules, lymph nodes, retro-esophageal location of adenomas and ectopic and small parathyroid glands. CONCLUSIONS: Surgeon performed ultrasound is a useful adjunctive tool to MIBI localization for facilitating MIP and when performed by experienced parathyroid surgeons, it can achieve accuracy rates equivalent to that of a dedicated parathyroid radiologist.

Loss of heterozygosity of 17p13, with possible involvement of ACADVL and ALOX15B, in the pathogenesis of adrenocortical tumors.

OBJECTIVE: To determine the minimal common region of loss on 17p13 in a cohort of adrenocortical carcinomas (ACCs) (defined by a Weiss score > or =3) and adrenocortical adenomas (ACAs) (defined by a Weiss score <3) and subsequently to assess 3 genes in this region that could be involved in adrenocortical tumorigenesis. SUMMARY BACKGROUND DATA: Loss of heterozygosity (LOH) of 17p13 has been demonstrated to occur more frequently in ACCs compared with ACAs. METHODS: Using 12 microsatellite markers across 17p13, LOH analysis was performed on 37 paired blood and adrenocortical tumor samples (23 ACC and 14 ACA samples) to determine the minimal common region of loss for ACCs and ACAs. From this minimal region of loss, 3 genes were selected for quantitative real time reverse transcription polymerase chain reaction analysis on 20 ACCs and 30 ACAs. RESULTS: LOH at 17p13 was found in 74% of ACCs compared with 14% of ACAs. There was a 10.4-Mb common minimal region of loss in ACCs whereas no minimal region of loss in ACAs could be demonstrated. Expression of Acyl coenzyme-A dehydrogenase very long chain (ACADVL) and Arachidonate 15-lipoxygenase second type (ALOX15B) was significantly down-regulated in ACCs compared with ACAs whereas there was no difference in expression of Potassium channel tetramerization domain containing 11 (KCTD11) in ACCs and ACAs. CONCLUSIONS: We demonstrated a minimal common region of loss of 10.4-Mb on 17p13 in ACCs and within this region, we found that ACADVL and ALOX15B expression are good discriminators between ACCs and ACAs.

Minimally invasive parathyroidectomy using the lateral focused miniincision approach: Is there a learning curve for surgeons experienced in the open procedure?

BACKGROUND: Minimally invasive parathyroidectomy (MIP) has gained acceptance as the standard of care for management of primary hyperparathyroidism in which a single adenoma can be localized. The aim of this study was to determine if there is a learning curve for MIP using the lateral focused miniincision approach performed by surgeons experienced in open parathyroidectomy. STUDY DESIGN: This is a retrospective case series comprising all parathyroid operations undertaken by three surgeons in the University of Sydney Endocrine Surgical Unit from 2003 to 2005. Outcomes of the experienced surgeon were compared with those of the two surgeons commencing practice. RESULTS: There were 699 parathyroidectomies performed in the Unit during the 36-month period (experienced surgeons: 438 versus commencing physicians: 261). Of the parathyroidectomies performed, 57% done by experienced surgeons were minimally invasive compared with 38% of those performed by surgeons commencing practice (p < 0.001). There were no differences in the number of complications (p = 0.21), conversions to open exploration (p = 0.6), and cure rates (p = 0.9) in the MIP patients in both groups. The initial (first 131 patients) and subsequent (next 130 patients) parathyroidectomy experiences of surgeons commencing practice were examined. In the initial experiences, 28% of the cases were minimally invasive compared with 48% in the subsequent experiences (p < 0.001). There were no differences in the number of complications (p = 0.3), conversions to open exploration (p = 0.9), and cure rates (p = 0.9). CONCLUSIONS: For surgeons experienced in open parathyroidectomy, there is no technical learning curve using the lateral focused miniincision technique for MIP. There is, however, a learning curve for patient selection.

Use of the ligaSure vessel sealing system in laparoscopic adrenalectomy.

Laparoscopic adrenalectomy is the operation of choice for benign adrenal lesions. During laparoscopic surgery, vessels are usually ligated with diathermy, ligaclips, staplers or ultrasonic coagulators. Use of the electrothermal bipolar vessel sealer (LigaSure; Valleylab, Boulder, CO, USA) has recently been described in a variety of procedures, not including adrenalectomy. This article is a retrospective study of 28 patients undergoing laparoscopic adrenalectomy within the University of Sydney Endocrine Surgical Unit at the Royal North Shore Hospital using the LigaSure vessel sealing system. Between July 2004 and August 2005, 28 consecutive patients underwent laparoscopic adrenalectomy using the LigaSure vessel sealing system to divide feeding adrenal vessels as well as the adrenal vein. There were no bleeding complications. The LigaSure vessel sealing system can be safely used to secure haemostasis, including division of the adrenal vein, in laparoscopic adrenalectomy.

Serum intact parathyroid hormone as a predictor of hypocalcaemia after total thyroidectomy.

BACKGROUND: Hypocalcaemia from hypoparathyroidism is a complication of total thyroidectomy. The aim of the present study was to determine whether an early postoperative level of serum parathyroid hormone (PTH) after total thyroidectomy predicts the development of significant hypocalcaemia and the need for treatment. METHODS: Patients undergoing total thyroidectomy had their serum level of intact PTH checked 1 h after removal of the thyroid gland. Serum calcium level was checked on the following morning. Oral calcium and/or calcitriol was commenced if the patient developed hypocalcaemic symptoms, or if the corrected serum calcium level was <2.0 mmol/L. RESULTS: Seventy-nine patients were included in the present study. Thirteen patients had symptoms of hypocalcaemia on postoperative days 1 or 2 and 66 patients remained asymptomatic. The postoperative intact PTH, day 1 calcium and day 2 calcium was 0.32 +/- 0.60 pmol/L, 2.01 +/- 0.11 mmol/L, and 2.02 +/- 0.16 mmol/L, respectively, for the symptomatic group and 1.98 +/- 1.25, 2.21 +/- 0.13, and 2.19 +/- 0.14, respectively, for the asymptomatic group. Calcium support was given to 25 patients, of whom 14 also required calcitriol. CONCLUSION: Serum PTH 1-h after total thyroidectomy is a reliable predictor of hypocalcaemia and can allow safe early discharge of patients from hospital.