Metastatic adrenocortical carcinoma displays higher mutation rate and tumor heterogeneity than primary tumors

Adrenocortical carcinoma: presentation and outcome of a contemporary patient series

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare endocrine carcinoma with poor 5-year survival rates of < 40%. According to the literature, ACC is rarely an incidental imaging finding. However, presentation, treatment and outcome may differ in modern series.

DESIGN AND METHODS

We studied all patients (n = 47, four children) from a single centre during years 2002-2018. We re-evaluated radiologic and histopathological findings and assessed treatments and outcome. We searched for possible TP53 gene defects and assessed nationwide incidence of ACC.

RESULTS

In adults, incidental radiologic finding led to diagnosis in 79% at median age of 61 years. ENSAT stage I, II, III and IV was 19%, 40%, 19% and 21%, respectively. Nonenhanced CT demonstrated > 20 Hounsfield Units (HU) for all tumours (median 34 (21-45)), median size 92 mm (20-196), Ki67 17% (1-40%), Weiss score 7 (4-9) and Helsinki score 24 (4-48). ACC was more often found in the left than the right adrenal (p < 0.05). One child had Beckwith-Wiedemann and one a TP53 mutation. In adults, the primary tumour was resected in 88 and 79% received adjuvant mitotane therapy. Median hospital stay was significantly shorter in the laparoscopic vs. open surgery group (4 (3-7) vs. 8 (5-38) days, respectively; p < 0.001). In 3/4 patients, prolonged remission of > 5 to > 10 years was achieved after repeated surgery of metastases. Overall 5-year survival was 67%, and 96% vs. 26% for ENSAT stage I-II vs. III-IV (p < 0.0001). ENSAT stage and Ki67 predicted survival, type of surgery did not. Mitotane associated with better survival.

CONCLUSIONS

Contemporary ACC predominantly presents as an incidental imaging finding, characterised by HU > 20 on nonenhanced CT but variable tumour size (20-196 mm). Malignancy cannot be ruled out by small tumour size only. The 5-year survival of 96% in ENSAT stage I-III compares favourably to previous studies.

SIRT6 abrogation promotes adrenocortical carcinoma through activation of NF-κB signaling

As an uncommon malignancy in the adrenal gland, adrenocortical carcinoma (ACC) is characterized by thorny diagnosis and poor clinical outcome, necessitating innovative treatment strategies. Sirtuin 6 (SIRT6), a tumor suppressor, modulates aerobic glycolysis of malignant cells and has an impact on tumorigenesis. This study focused on investigating SIRT6 expression in ACC and how it generates cancer phenotypes. SIRT6 expression was inhibited in ACC tissues according to western blotting, real-time polymerase chain reaction, and immunohistochemistry. MTT assay, TUNEL assay, and flow cytometry were performed to evaluate the contribution of SIRT6 to cell invasion, proliferation, death, and migration. It was shown that SIRT6 knockdown promoted cell invasion, proliferation, and migration, and inhibited cell death. Moreover, it was found that SIRT6 knockdown upregulated TLR4 and reinforced phosphorylation of the nuclear transcription factor-kappa B (NF-κB) subunit p65 as well as inhibitor of nuclear factor kappa-B kinase. Additionally, SIRT6 knockdown significantly enhanced expression of calcitonin gene-related peptide as well as transient receptor potential vanilloid subtype 1. It also reinforced reactive oxygen species generation. Overall, our research findings demonstrate that SIRT6 serves as a tumor suppressor via regulation of the NF-κB pathway, which could offer an innovative strategy to treat ACC.

Molecular Drivers of Potential Immunotherapy Failure in Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare, highly aggressive cancer, often insensitive to conventional chemotherapeutics agents. Early diagnosis, followed by radical surgical resection plus/minus adjuvant mitotane therapy, is nowadays the only valuable option. Unfortunately, one out of four patients has metastatic disease at diagnosis and most of radically resected ACC patients are destined to recur with local or metastatic disease. Numerous efforts aimed at identifying molecular alterations crucial for ACC pathogenesis have been extensively conducted, with the hope to develop new treatments. Indeed, multiple genes and pathways have been identified as potentially targetable in ACC patients; however, despite the strong preclinical rationale, translational findings to clinical trials led to date to disappointing results. The immunotherapeutic intervention targeting T-cell checkpoint molecules has been proposed as well, but results obtained in early studies indicate that ACC patients would be unlikely to benefit from immunotherapy. Genetic alterations of different pathways involved in ACC carcinogenesis are also known substrates of resistance to immunotherapy. Among them, β-catenin gene CTNNB1 and TP53 gene are frequently mutated in ACC samples. Overactivation of the β-catenin pathway and loss of p53 protein function are potential tumor-intrinsic factors that, impacting on the ability of ACC cells to recruit dendritic cells, leading to T-cell exclusion, put this tumor among those that are potentially resistant to immunotherapy. Moreover, the steroid phenotype, which implies glucocorticoids hypersecretion in a subset of ACC, contributes to generating an immunosuppressive microenvironment. Here, we review clinical results of immunotherapy in ACC and we highlight molecular mechanisms driving immunotherapy failure in ACC, suggesting possible approaches to overcome resistance.

Clinical characteristics and prognosis of adrenocortical tumors in children

PURPOSE

The purpose of this study was to review the clinical characteristics and prognosis of children with adrenocortical tumors (ACT).

METHODS

We retrospectively reviewed the medical records of 28 patients with ACT at our hospital between March 2010 and March 2017.

RESULTS

The main clinical presentations were sexual prematurity (n = 17) and Cushing's syndrome (n = 15). All patients without metastasis underwent complete resection by laparotomy (n = 19) or laparoscopic surgery (n = 9). Pathological diagnosis confirmed adrenocortical carcinomas (ACC, n = 12) and adrenocortical adenomas (ACA, n = 16). Dehydroepiandrosterone (939.4 ± 148.2 µg/dl vs 630.9 ± 376.3 µg/dl; p = 0.031) and testosterone (235.7 ± 89.1 ng/dl vs 164.6 ± 47.5 ng/dl; p = 0.012) were significantly increased in ACC compared with ACA. The ACC tumor volumes were larger than those in ACA (107.5 ± 69 vs 25.5 ± 23.1 cm³; average diameter 6 cm vs 4 cm p = 0.001) and the immunochemical expression of Ki-67 was higher in ACC than in ACA (30.2 ± 22.7 vs 9.9 ± 4.9 p = 0.013). The mean follow-up of patients with ACA was 40 ± 23 months without recurrence. Seven patients with ACC had postoperative distant metastases and five patients died within 2 years. Five patients with ACC survived with a median follow-up of 27 months. The 2-year overall survival was 44.6%.

CONCLUSIONS

Patients with ACC had significantly larger tumor volumes than those with ACA. The discordantly elevated serum levels of sexual corticosteroid hormones and lactate dehydrogenase may predict the malignant nature of these tumors. The prognosis of patients with ACA was good, while those with ACC had high postoperative metastasis and mortality rates.