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 (^EGFREDV^TM 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 EDV^TM nanoparticles. This data is the first study in ACC investigating the possibility of miRNAs replacement as a novel therapy.

Long noncoding RNA profiles of adrenocortical cancer can be used to predict recurrence

Adrenocortical carcinoma (ACC) is an aggressive malignancy with high rates of recurrence following surgical resection. Long noncoding RNAs (lncRNAs) play an important role in cancer development. Pathogenesis of adrenal tumours have been characterised by mRNA, microRNA and methylation expression signatures, but it is unknown if this extends to lncRNAs. This study describes lncRNA expression signatures in ACC, adrenal cortical adenoma (ACA) and normal adrenal cortex (NAC) and presents lncRNAs associated with ACC recurrence to identify novel prognostic and therapeutic targets. RNA was extracted from freshly frozen tissue with confirmation of diagnosis by histopathology. Focused lncRNA and mRNA transcriptome analysis was performed using the ArrayStar Human LncRNA V3.0 microarray. Differentially expressed lncRNAs were validated using quantitative reverse transcriptase-PCR and correlated with clinical outcomes. Microarray of 21 samples (ten ACCs, five ACAs and six NACs) showed distinct patterns of lncRNA expression between each group. A total of 956 lncRNAs were differentially expressed between ACC and NAC, including known carcinogenesis-related lncRNAs such as H19, GAS5, MALAT1 and PRINS (P≤0.05); 85 lncRNAs were differentially expressed between ACC and ACA (P≤0.05). Hierarchical clustering and heat mapping showed ACC samples correctly grouped compared with NAC and ACA. Sixty-six differentially expressed lncRNAs were found to be associated with ACC recurrence (P≤0.05), one of which, PRINS, was validated in a group of 20 ACCs and also found to be associated with metastatic disease on presentation. The pathogenesis of adrenal tumours extends to lncRNA dysregulation and low expression of the lncRNA PRINS is associated with ACC recurrence.

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.

Microarray gene expression and immunohistochemistry analyses of adrenocortical tumors identify IGF2 and Ki-67 as useful in differentiating carcinomas from adenomas

The management of adrenocortical tumors (ACTs) is complex. The Weiss score is the present most widely used system for ACT diagnosis. An ACT is scored from 0 to 9, with a higher score correlating with increased malignancy. However, ACTs with a score of 3 can be phenotypically benign or malignant. Our objective is to use microarray profiling of a cohort of adrenocortical carcinomas (ACCs) and adrenocortical adenomas (ACAs) to identify discriminatory genes that could be used as an adjunct to the Weiss score. A cohort of Weiss score defined ACCs and ACAs were profiled using Affymetrix HGU133plus2.0 genechips. Genes with high-discriminatory power were identified by univariate and multivariate analyses and confirmed by quantitative real-time reverse transcription PCR and immunohistochemistry (IHC). The expression of IGF2, MAD2L1, and CCNB1 were significantly higher in ACCs compared with ACAs while ABLIM1, NAV3, SEPT4, and RPRM were significantly lower. Several proteins, including IGF2, MAD2L1, CCNB1, and Ki-67 had high-diagnostic accuracy in differentiating ACCs from ACAs. The best results, however, were obtained with a combination of IGF2 and Ki-67, with 96% sensitivity and 100% specificity in diagnosing ACCs. Microarray gene expression profiling accurately differentiates ACCs from ACAs. The combination of IGF2 and Ki-67 IHC is also highly accurate in distinguishing between the two groups and is particularly helpful in ACTs with Weiss score of 3.

Molecular basis of adrenocortical carcinomas

Adrenocortical carcinomas (ACCs) are rare tumors associated with poor prognosis. Although surgery is the mainstay of treatment for this cancer, most patients will experience a recurrence of their tumor. Adjuvant therapies currently include mitotane, radiotherapy and chemotherapy, but responses to these therapies, however, are poor. A better understanding of the molecular basis of this cancer is crucial to the development of newer and better treatment options. This review summarizes the current knowledge of the molecular basis of ACCs.

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.

Laparoscopic surgery is safe for large adrenal lesions

INTRODUCTION

Laparoscopic adrenalectomy has surpassed open adrenalectomy as the gold standard for excision of benign adrenal lesions. The size threshold for offering laparoscopic adrenalectomy is controversial as the prevalence of adrenocortical carcinoma increases with increasing tumour size. The aim of this paper was to assess the safety of laparoscopic adrenalectomy for large adrenal tumours (tumours > or = 60 mm).

METHODS

A retrospective cohort study of patients who underwent adrenalectomy in a single unit during the period 1995-2005 was undertaken.

RESULTS

One hundred and seventy patients with 173 tumours were included in this study. Of these, 29 were > or = 60 mm in size, and 16 of these patients underwent laparoscopic adrenalectomy. There were 8 adrenocortical carcinomas in the group with tumours > or = 60 mm in size. Five of these patients underwent an open adrenalectomy, while 2 and 1 patients had laparoscopic and laparoscopic converted to open adrenalectomy respectively. Four of the patients undergoing open adrenalectomy died of their disease while 1 is alive with recurrence 3 years later. The 3 patients who underwent either laparoscopic or laparoscopic converted to open adrenalectomy are alive without evidence of disease after 18 months follow up.

CONCLUSION

Our data show that patients with tumours > or = 60 mm with no preoperative or intraoperative evidence of malignancy can undergo laparoscopic adrenalectomy without evidence of recurrence on short term follow up. These findings are concordant with the growing body of literature supporting laparoscopic adrenalectomy for potentially malignant tumours > or = 60 mm in size without preoperative or intraoperative features of malignancy.

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.

Seroma formation after axillary lymphadenectomy with and without the use of drains

Seroma formation after axillary lymphadenectomy is common. We performed a randomised controlled trial comparing seroma rate and volume after axillary lymphadenectomy with and without use of drains. In this study, there was no difference in incidence of seroma formation between patients who did and did not have a drain inserted after axillary lymphadenectomy for breast cancer. Undrained patients, however, had larger volume seromas of longer duration which required more aspirations. There was a tendency for undrained patients to have fewer complications when compared to patients with drains.

Echogenicity of breast cancer: is it of prognostic value?

Echogenicity of colorectal metastases to the liver has been shown to correlate with prognosis. While there have been many studies looking at the echogenicity of breast cancer, there has been no study relating the issue of echogenicity to prognosis of breast cancer. In this study, we found that hyperechoic and mixed echogenicity breast cancers are rare compared to hypoechoic breast cancers. There was, however, no difference in the groups with respect to histological size, grade, axillary metastases, hormone receptor status and lymphovascular invasion.

Breast cancer presenting initially with urinary incontinence: a case of bladder metastasis from breast cancer

Bladder metastasis from breast cancer is rare. Patients with breast cancer, in particular patients with a lobular carcinoma subtype, who present with urinary symptoms including incontinence, hematuria, dysuria, and frequency should have the possibility of bladder metastases kept in mind and investigated with cystoscopy and imaging as necessary.