Overexpression of ERBB-2 was more frequently detected in malignant than benign pheochromocytomas by multiplex ligation-dependent probe amplification and immunohistochemistry

Value of Immunohistochemical Expression of Apelin, Succinate Dehydrogenase B, Chromogranin B, Human Epidermal Growth Factor Receptor-2, Contactin 4, and Succinyl-CoA Synthetase Subunit Beta in Differentiating Metastatic From Non-Metastatic Pheochromocytoma and Paraganglioma

OBJECTIVE

We aimed to retrospectively collect pathologically identified pheochromocytoma and paraganglioma (PPGL) tumor tissues from our center and investigate the expression of apelin and succinyl-CoA synthetase subunit beta (SUCLG2), human epidermal growth factor receptor-2 (HER2 or ERBB-2), contactin 4 (CNTN4), chromogranin B (CHGB), and succinate dehydrogenase B (SDHB) in metastatic and non-metastatic PPGLs, for exploring their roles in the diagnosis of metastatic PPGLs.

METHODS

A total of 369 patients with pathologically and surgically confirmed PPGLs at Xiangya Hospital, Central South University, between June 2010 and June 2020 were retrospectively included. Sixty patients-12 patients with metastatic PPGLs and 48 patients with non-metastatic PPGLs-were selected through propensity score matching (1:4) to reduce the effect of PPGL type, sex, and age. We observed and quantified the expression of apelin, SDHB, CHGB, ERBB-2, CNTN4, and SUCLG2 in paraffin-embedded samples using immunohistochemical staining.

RESULTS

No significant differences were observed between the metastatic group and non-metastatic group with respect to the expression of CNTN4 and SUCLG2. The expression of apelin, SDHB, CHGB, and ERBB-2 was significantly different between the two groups. The expression of apelin, SDHB, and CHGB was significantly lower in the metastatic group than that in the non-metastatic group (P < 0.001). ERBB-2 expression was significantly higher in the metastatic group than in the non-metastatic group (P = 0.042). Kaplan-Meier analysis revealed that patients with negative expression of apelin, SDHB, and CHGB showed significantly lower metastasis-free survival than those with positive expression. Multivariate Cox analysis revealed that SDHB and CHGB levels were independently associated with metastasis-free survival.

CONCLUSION

The expression levels of apelin, CHGB, SDHB, and ERBB-2 may be predictive biomarkers for the diagnosis of metastatic PPGLs. Patients with negative expression of apelin, CHGB, and SDHB should be subjected to frequent postoperative follow-up procedures.

Genetic and epigenetic differences of benign and malignant pheochromocytomas and paragangliomas (PPGLs)

Pheochromocytomas and paragangliomas (PPGLs) are tumors arising from the adrenal medulla and sympathetic/parasympathetic paraganglia, respectively. According to Th e Cancer Genome Atlas (TCGA), approximately 40% of PPGLs are due to germ line mutations in one of 16 susceptibility genes, and a further 30% are due to somatic alterations in at least seven main genes (VHL, EPAS1, CSDE1, MAX, HRAS, NF1, RET, and possibly KIF1B). Th e diagnosis of malignant PPGL was straight forward in most cases as it was defined as presence of PPGL in non-chromaffin tissues. Accordingly, there is an extreme need for new diagnostic marker(s) to identify tumors with malignant prospective. Th e aim of this study was to review all suggested genetic and epigenetic alterations that are remarkably different between benign and malignant PPGLs. It seems that more than two genetic mutation clusters in PPGLs and other genetic and methylation biomarkers could be targeted for malignancy discrimination in different studies.

Establishment and evaluation of a novel biomarker-based nomogram for malignant phaeochromocytomas and paragangliomas

OBJECTIVE

No single histological or molecular marker is diagnostic for malignant phaeochromocytomas and paragangliomas (PPGLs). This study aimed to establish and evaluate a prognostic nomogram to improve the prediction of metastatic probability in individual PPGL patients.

METHODS

Three hundred and 47 consecutive PPGL patients from January 2002 through December 2014 were randomly divided into a training set (n=208) and a validation set (n=139). A multivariate logistic regression analysis of selected prognostic features was performed, and a nomogram to predict metastasis was constructed. Discrimination and calibration were employed to evaluate the performance of the nomogram. Clinical usefulness was calculated using decision curve analysis.

RESULTS

The overall metastatic rate was 10.6%. Primary tumour size, primary tumour location, vascular invasion, ERBB-2 overexpression, SDHB mutation and catecholamine type were associated with malignancy in the logistic analysis and were included in the nomogram. The nomogram showed an area under the receiver operating characteristic curve (AUC) of 0.872 (95% confidence interval [CI], 0.819-0.914) in the training set. The validation set showed good discrimination, with an AUC of 0.870 (95% CI, 0.803-0.921). The nomogram was well calibrated, with no significant difference between the predicted and the observed probabilities (Hosmer-Lemeshow test: P=.510 for the training set; .314 for the validation set). Decision curve analysis revealed that molecular markers (ERBB-2 overexpression and SDHB mutation) could increase the clinical benefit of the nomogram.

CONCLUSION

Our results support the use of the present biomarker-based nomogram, which has good discriminative ability, to predict the metastatic probability of PPGLs.

ERBB-2 overexpression as a risk factor for malignant phaeochromocytomas and paraganglinomas

OBJECTIVE

There are currently no good histological or molecular markers to differentiate benign from malignant phaeochromocytomas and paraganglinomas (PPGLs). Our previous cross-sectional study observed that ERBB-2 overexpression was associated with malignant PPGLs. This study aimed to evaluate the predictive value of ERBB-2 overexpression for metastasis in PPGLs in a large population.

METHODS

A total of 262 patients diagnosed as PPGLs in our institution between 2002 and 2012 were included. We analysed ERBB-2 protein expression in the primary PPGL tumours by immunohistochemistry (IHC) and ERBB-2 amplification by fluorescence in situ hybridization (FISH). Direct Sanger sequencing was performed to examine ERBB-2 exon 20 mutations. The occurrence of malignant PPGLs was documented in the follow-up period. Kaplan-Meier analysis and Cox proportional hazard models were used to evaluate the association between ERBB-2 overexpression and metastasis of PPGLs.

RESULTS

Twenty-six (9·9%) patients had ERBB-2 overexpression in their primary PPGL tumours, which was significantly associated with ERBB-2 amplification (17/25, 68%). No ERBB-2 mutation was found. At a median follow-up of 4·5 years, a total of 23 malignant PPGLs were documented, including eight (30·8%) patients in the ERBB-2 overexpression group and 15 (6·4%) patients in the ERBB-2-negative group. The incidence rate of metastasis was 5·3 per 100 person-years vs 1·4 per 100 person-years in the ERBB-2 overexpression and ERBB-2-negative groups (P < 0·001), respectively. Kaplan-Meier analysis showed that ERBB-2 overexpression was associated with decreased metastasis-free survival (P = 0·001, log-rank test). After adjusting for primary tumour size and location, Cox regression analysis revealed that ERBB-2 overexpression was independently associated with risk of malignant PPGLs (HR = 2·78; 95% CI, 1·12-6·90; P = 0·028).

CONCLUSION

Patients harbouring tumours with ERBB-2 overexpression have a significantly higher risk of developing malignant PPGLs.

Target therapy in metastatic pheochromocytoma: current perspectives and controversies

Most of the pheochromocytomas (PCCs) are benign neoplasms, but when they are malignant, they can be difficult to treat. Despite advances in diagnosis and imaging, it remains an untreatable tumor, when metastases develop. A deeper understanding of the alteration of the specific molecular pathways causing malignant PCCs might hopefully lead in the future to the development of multiple molecular-targeted therapies to treat it successfully. Clinical experience and the use of murine models of metastatic PCCs have helped introduce new experimental treatment options which will significantly help the PCCs community explore novel targeted therapies that have already shown promising results in many other types of tumors.

Paragangliomas: update on differential diagnostic considerations, composite tumors, and recent genetic developments

Recent developments in molecular genetics have expanded the spectrum of disorders associated with pheochromocytomas (PCCs) and extra-adrenal paragangliomas (PGLs) and have increased the roles of pathologists in helping to guide patient care. At least 30% of these tumors are now known to be hereditary, and germline mutations of at least 10 genes are known to cause the tumors to develop. Genotype-phenotype correlations have been identified, including differences in tumor distribution, catecholamine production, and risk of metastasis, and types of tumors not previously associated with PCC/PGL are now considered in the spectrum of hereditary disease. Important new findings are that mutations of succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD, and SDHAF2 (collectively "SDHx") are responsible for a large percentage of hereditary PCC/PGL and that SDHB mutations are strongly correlated with extra-adrenal tumor location, metastasis, and poor prognosis. Further, gastrointestinal stromal tumors and renal tumors are now associated with SDHx mutations. A PCC or PGL caused by any of the hereditary susceptibility genes can present as a solitary, apparently sporadic, tumor, and substantial numbers of patients presenting with apparently sporadic tumors harbor occult germline mutations of susceptibility genes. Current roles of pathologists are differential diagnosis of primary tumors and metastases, identification of clues to occult hereditary disease, and triaging of patients for optimal genetic testing by immunohistochemical staining of tumor tissue for the loss of SDHB and SDHA protein. Diagnostic pitfalls are posed by morphological variants of PCC/PGL, unusual anatomic sites of occurrence, and coexisting neuroendocrine tumors of other types in some hereditary syndromes. These pitfalls can be avoided by judicious use of appropriate immunohistochemical stains. Aside from loss of staining for SDHB, criteria for predicting risk of metastasis are still controversial, and "malignancy" is diagnosed only after metastases have occurred. All PCCs/PGLs are considered to pose some risk of metastasis, and long-term follow-up is advised.

Current and future therapeutic approaches for metastatic pheochromocytoma and paraganglioma: focus on SDHB tumors

As a result of intense genetic studies of families with specific mutations, the road to better therapeutic intervention for pheochromocytoma (PHEOs) and parangangliomas (PGLs) has more recently become populated with several promising molecular targets. Consequently a change in paradigm from a previous view on nonspecific therapy has shifted towards more selective molecular targeted therapies. In particular, malignant PHEOs/PGLs, more specifically the tumors that result from mutations in succinate dehydrogenase subunit B (SDHB), are a clear concern, and novel therapies should be developed to address this problem. Here we summarize current and future therapeutic approaches.

Gene expression profiles of phaeochromocytomas with ERBB2 overexpression reveal a new molecular mechanism tumourigenicity

OBJECTIVE

Phaeochromocytomas (PHEO) and functional paragangliomas (PGLs) are catecholamine-secreting neuroendocrine tumours. Although most PHEO/PGLs are benign, 10-35% present as (or develop into) malignant tumours with a poor prognosis. Overexpression of ERBB2 (v-erb-b2 erythroblastic leukaemia viral oncogene homologue 2) has been reported to be associated with malignant PHEO. We used gene expression profiling of PHEO/PGLs to gain a better understanding of the tumourigenic pathways associated with ERBB2.

METHODS

We used the Affymetrix Gene Chip U133 Plus 2·0 genome-wide gene expression cDNA microarray of 18 PHEO/PGLs (12 benign and six malignant, divided into two groups depending on ERBB2 expression levels) to analyse the gene expression patterns.

RESULTS

Unsupervised hierarchical cluster analysis of transcription profiles of 18 samples identified two dominant expression clusters corresponding to samples belonging to the ERBB2+ and ERBB2- groups. According to the gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases, the differentially expressed genes were classified into diverse functional categories and signalling pathways. In particular, the focal adhesion signalling pathway showed significant differences between the groups; specifically, the FAK-Src-MAPK pathway was prominently activated in the ERBB2+ group.

CONCLUSIONS

In summary, ERBB2+ PHEO/PGLs have a distinct expression pattern compared with the ERBB2- group. The focal adhesion signalling pathway may participate in ERBB2-induced tumourigenesis in PHEO/PGLs.

Pheochromocytomas and paragangliomas: assessment of malignant potential

Pheochromocytomas and paragangliomas (PPGLs) are rare catecholamine-secreting tumors which arise from the adrenal glands or sympathetic neuronal tissue. Malignant transformation of these tumors occurs in a significant proportion and may therefore lower overall survival rates. In patients with PPGLs it is impossible to identify malignant disease without the presence of metastatic disease, something which can occur as long as 20 years after initial surgery. Early identification of malignant disease would necessitate a more aggressive treatment approach, something which may result in better disease outcome. We have therefore reviewed possible predictors of malignancy and current developments in order to help clinicians to swiftly assess malignant potential in patients with PPGLs. Currently, there is no absolute marker which can objectively reflect malignant potential. Tumor size is the most reliable predictor and should therefore be used as the baseline characteristic. The combination of various clinical markers (extra-adrenal disease and post-operative hypertension), biochemical markers (high dopamine, high norepinephrine and epinephrine to total catecholamine ratio) and/or histological markers (SNAIL, microRNAs and/or microarray results) can raise or lower the suspicion of malignancy. Furthermore, we discuss how clinical markers may affect biochemical results linked to malignancy, how biochemical results may distinguish hereditary syndromes, the role of imaging in determining malignant potential and tumor detection, and recent results of proposed histological markers.

Malignant pheochromocytomas and paragangliomas: a diagnostic challenge

INTRODUCTION

Malignant pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare disorders arising from the adrenal gland, from the glomera along parasympathetic nerves or from paraganglia along the sympathetic trunk. According to the WHO classification, malignancy of PCCs and PGLs is defined by the presence of metastases at non-chromaffin sites distant from that of the primary tumor and not by local invasion. The overall prognosis of metastasized PCCs/PGLs is poor. Surgery offers currently the only change of cure. Preferably, the discrimination between malignant and benign PCCs/PGLs should be made preoperatively.

METHODS

This review summarizes our current knowledge on how benign and malignant tumors can be distinguished.

CONCLUSION

Due to the rarity of malignant PCCs/PGLs and the obvious difficulties in distinguishing benign and malignant PCCs/PGLs, any patient with a PCC/PGL should be treated in a specialized center where a multidisciplinary setting with specialized teams consisting of radiologists, endocrinologist, oncologists, pathologists and surgeons is available. This would also facilitate future studies to address the existing diagnostic and/or therapeutic obstacles.

Changing paradigms in the treatment of malignant pheochromocytoma

BACKGROUND

Pheochromocytomas and paragangliomas are intra- and extra-adrenal neoplasms that are rarely malignant. The treatment of those that are malignant has remained a challenge because little was known about the molecular pathways involved in its malignant transformation. Recently, however, the genetic and molecular changes involved in malignant pheochromocytoma have come to be understood.

METHODS

The authors review the recent literature about the changing treatment options for malignant pheochromocytomas and paragangliomas.

RESULTS

Traditional treatments for malignant pheochromocytoma remain unsuccessful. With the advances made in genomics and proteomics, novel pathways in pheochromocytoma carcinogenesis are becoming the targets of new treatment strategies and show promising results.

CONCLUSIONS

Although several studies and clinical trials show great promise for improving the treatment of pheochromocytomas and paragangliomas, the hope is that future collaborative efforts will allow for prospective clinical trials using an evidenced-based approach.