Whole-genome and transcriptome analysis of advanced adrenocortical cancer highlights multiple alterations affecting epigenome and DNA repair pathways

Adrenocortical stem cells in health and disease

The adrenal cortex is the major site of production of steroid hormones, which are essential for life. The normal development and homeostatic renewal of the adrenal cortex depend on capsular stem cells and cortical progenitor cells. These cell populations are highly plastic and support adaptation to physiological demands, injury and disease, linking steroid production and adrenal (organ) homeostasis with systemic endocrine cues and organismal homeostasis. This Review integrates findings from the past decade, outlining the mechanisms that govern the establishment and maintenance of the adrenal stem cell niche under different physiological and pathological conditions. The sophisticated regulation of the stem cell niche by gene regulatory networks, coordinated through paracrine and endocrine signalling, is highlighted in a context-dependent and sex-specific manner. We discuss how dysregulation of this intricate regulatory network is implicated in a wide range of adrenal diseases, and how emerging knowledge from adrenal stem cell research is inspiring the future development of gene-based and cell-based therapeutic strategies.

Advances in translational research of the rare cancer type adrenocortical carcinoma

Adrenocortical carcinoma is a rare malignancy with an annual worldwide incidence of 1-2 cases per 1 million and a 5-year survival rate of <60%. Although adrenocortical carcinoma is rare, such rare cancers account for approximately one third of patients diagnosed with cancer annually. In the past decade, there have been considerable advances in understanding the molecular basis of adrenocortical carcinoma. The genetic events associated with adrenocortical carcinoma in adults are distinct from those of paediatric cases, which are often associated with germline or somatic TP53 mutations and have a better prognosis. In adult primary adrenocortical carcinoma, the main somatic genetic alterations occur in genes that encode proteins involved in the WNT-β-catenin pathway, cell cycle and p53 apoptosis pathway, chromatin remodelling and telomere maintenance pathway, cAMP-protein kinase A (PKA) pathway or DNA transcription and RNA translation pathways. Recently, integrated molecular studies of adrenocortical carcinomas, which have characterized somatic mutations and the methylome as well as gene and microRNA expression profiles, have led to a molecular classification of these tumours that can predict prognosis and have helped to identify new therapeutic targets. In this Review, we summarize these recent translational research advances in adrenocortical carcinoma, which it is hoped could lead to improved patient diagnosis, treatment and outcome.

Molecular Cluster Mining of Adrenocortical Carcinoma via Multi-Omics Data Analysis Aids Precise Clinical Therapy

Adrenocortical carcinoma (ACC) is a malignancy of the endocrine system. We collected clinical and pathological features, genomic mutations, DNA methylation profiles, and mRNA, lncRNA, microRNA, and somatic mutations in ACC patients from the TCGA, GSE19750, GSE33371, and GSE49278 cohorts. Based on the MOVICS algorithm, the patients were divided into ACC1-3 subtypes by comprehensive multi-omics data analysis. We found that immune-related pathways were more activated, and drug metabolism pathways were enriched in ACC1 subtype patients. Furthermore, ACC1 patients were sensitive to PD-1 immunotherapy and had the lowest sensitivity to chemotherapeutic drugs. Patients with the ACC2 subtype had the worst survival prognosis and the highest tumor-mutation rate. Meanwhile, cell-cycle-related pathways, amino-acid-synthesis pathways, and immunosuppressive cells were enriched in ACC2 patients. Steroid and cholesterol biosynthetic pathways were enriched in patients with the ACC3 subtype. DNA-repair-related pathways were enriched in subtypes ACC2 and ACC3. The sensitivity of the ACC2 subtype to cisplatin, doxorubicin, gemcitabine, and etoposide was better than that of the other two subtypes. For 5-fluorouracil, there was no significant difference in sensitivity to paclitaxel between the three groups. A comprehensive analysis of multi-omics data will provide new clues for the prognosis and treatment of patients with ACC.

Bridging the Scientific Gaps to Identify Effective Treatments in Adrenocortical Cancer

Adrenocortical cancer (ACC) typically presents in advanced stages of disease and has a dismal prognosis. One of the foremost reasons for this is the lack of available systemic therapies, with mitotane remaining the backbone of treatment since its discovery in the 1960s, despite underwhelming efficacy. Surgery remains the only potentially curative option, but about half of patients will recur post-operatively, often with metastatic disease. Other local treatment options have been attempted but are only used practically on a case-by-case basis. Over the past few decades there have been significant advances in understanding the molecular background of ACC, but this has not yet translated to better treatment options. Attempts at novel treatment strategies have not provided significant clinical benefit. This paper reviews our current treatment options and molecular understanding of ACC and the reasons why a successful treatment has remained elusive. Additionally, we discuss the knowledge gaps that need to be overcome to bring us closer to successful treatment and ways to bridge them.