Tumor DNA Methylation Profiling Is a Robust and Independent Prognostic Marker for Pediatric Patients With Adrenocortical Tumors

Pediatric adrenocortical tumors (pACTs) display complex genomic background and lack robust prognostic biomarkers. However, pACT methylation profiling was recently associated with patient prognosis. In order to evaluate whether tumor DNA methylation is associated with patient prognosis, we studied a Brazilian cohort of pACT in which most of the patients were carriers of the germline P53 p.R337H mutation (86%). We analyzed the DNA methylation profile of 57 tumor samples (MethylationEPIC BeadChip Array, Illumina) and the respective patients’ clinicopathological features associated with outcome and overall survival. Median age at diagnosis of the 40 girls and 17 boys was 2.1 years (range: 0.2–16.6). Reduced overall survival was observed in patients diagnosed after 4 years of age (n=43, HR=26.5, p<0.0001, 5-year survival (5ys)=43%), in those presenting with Cushing’s syndrome (n=7, HR=12.5, p<0.0001, 5ys=28%), advanced/non localized disease (IPACTR stages III and IV; n=11, HR=12.9, p<0.0001, 5ys=33%) or carcinomas (n=10, HR=4.9, p=0.04 5ys=56%). Unsupervised analysis of methylation data (Euclidean distance and Ward’s method; Pvclust package, R, version 4.0.3) included all 766,031 probes filtered in by the quality control step, and revealed two groups with distinct methylation signatures with a bootstrap support of 99%, namely pACT1 and pACT2. The overall variance of differentially methylated probes (DMPs; FDR p-values <10–6 and, simultaneously, median M-value difference >2) between the groups was 0.084% (n=642 probes). Tumors from pACT1 were enriched for hypomethylation in genes’ body region and for hypermethylation in promoter regions (p<0.0001). Gene set analysis showed that DMPs were mostly enriched in gene sets involved in nervous system differentiation and development, mRNA binding, and peptide secretion and related to pathways in cancer, cell adhesion, and calcium signaling. Methylation was not associated with germline P53 p.R337H mutation (p=0.57). Compared to pACT2, pACT1 group comprised patients older at diagnosis (p=0.0004) and higher frequencies of patients diagnosed after 4 years of age (80 vs 13%; p<0.0001), presenting with Cushing syndrome (40 vs. 4%; p=0.01), non-localized/advanced disease (70 vs 8%; p=0.0001), carcinomas (71 vs 17%. p=0.009), who needed adjuvant chemotherapy (90 vs. 9%; p<0.0001), and who experienced post-surgery recurrence or metastasis (90 vs 6%; p<0.0001). pACT1 methylation signature was associated with reduced overall survival from the disease (HR=51, p=0.0001, 5ys: 20 vs 98%), and remained associated after adjusting for prognostic features. Interestingly, different tumor methylation signatures were associated with pACT clinical presentation and evolution, regardless the presence of the P53 p.R337H mutation. Our data supports the analysis of methylation profiling as a robust and independent prognostic biomarker for pACT.

SAT-LB36 Distinct Vitamin D Receptor DNA Methylation Profiles Are Associated With the Outcome of Pediatric Patients With Adrenocortical Tumors

Pediatric adrenocortical tumors (pACT) are rare, display complex genomic background and lack robust prognostic markers. Very recently, distinct genomic methylation profiles of pACT were associated with prognosis. The vitamin D receptor (VDR) was shown to be underexpressed in ACT, especially in carcinomas (ACC). In adult ACC, VDR inactivation by methylation was demonstrated. On the other hand, VDR activation was shown to inhibit ACC proliferation in vitro and in vivo.

Aim: To evaluate VDR DNA methylation profile and its clinical and prognostic significance in pediatric ACT.

Methods: Genomic DNA methylation from 57 pACTs [40 girls; median age: 2.1 (0.2-16.4) years] was assessed using Infininium Methylation EPIC BeadChip Array. Unsupervised hierarchical clustering analysis (Ward method, R Stats Package) was performed considering the M-values of the 49 probes targeting the whole extension of VDR gene contained in the array. Clinical, histopathological and molecular features, as well as pACT VDR mRNA levels (qPCR) and nuclear immunoreactivity (IHC) were used for association analysis.

Results: Hierarchical clustering identified three clusters of pACT. Methylated VDR-targeted probes (M-values different from 0; n=37) composed the VDR methylation profile, which differed significantly between the clusters [M-values: C1=1.77 (1.1-1.9) (low), C2=2.15 (1.7-2.7) (intermediate), and C3=2.65 (2.2-3.1) (high); p<0.0001]. The C1 cluster comprised a set of patients with favorable outcome (n=18), who were younger (p=0.035), did not present metastasis at diagnosis (IPACTR stage IV) or after surgery, nor were diagnosed with carcinomas (Wieneke criteria >=4), were not carriers of somatic Beta-catenin activating mutations, or died. Although cluster C2 patients (n=21) presented intermediary disease features, only 2 patients died and the overall outcome was positive. Instead, the C3 cluster concentrated patients (n=18) with non-localized/metastatic disease (IPACTR stages I/II vs. III/IV; p=0.004), post-surgical metastasis/recurrence (p=0.009), and patients who needed adjuvant chemotherapy (p=0.005). Moreover, C3 patients had lower overall and disease-free survival rates (log-rank: p=0.001 and p=0.014, respectively). VDR methylation was not associated with sex, clinical presentation, P53 mutations, nor with tumor VDR mRNA expression or nuclear immunoreactivity.

Conclusions: Three VDR methylation profiles were associated with distinct pACT clinical features and outcome. High VDR methylation was associated with worst outcome. Fully functioning VDR may play a beneficial role against pediatric adrenocortical tumorigenesis. This finding highlights the potential of targeting VDR as an adjuvant therapeutic target.

Outcomes of Patients with Central Precocious Puberty Due to Loss-of-Function Mutations in the MKRN3 Gene after Treatment with Gonadotropin-Releasing Hormone Analog

INTRODUCTION

Loss-of-function mutation of MKRN3 represents the most frequent genetic cause of familial central precocious puberty (CPP). The outcomes of gonadotropin-releasing hormone analog (GnRHa) treatment in CPP patients with MKRN3 defects are unknown.

OBJECTIVE

To describe the clinical and hormonal features of patients with CPP with or without MKRN3 mutations after GnRHa treatment. Anthropometric, metabolic and reproductive parameters were evaluated.

PATIENTS AND METHODS

Twenty-nine female patients with CPP due to loss-of-function mutations in the MKRN3 and 43 female patients with idiopathic CPP were included. Their medical records were retrospectively evaluated for clinical, laboratory, and imaging study, before, during, and after GnRHa treatment. All patients with idiopathic CPP and 11 patients with CPP due to MKRN3 defects reached final height (FH).

RESULTS

At the diagnosis, there were no significant differences between clinical and laboratory features of patients with CPP with or without MKRN3 mutations. A high prevalence of overweight and obesity was observed in patients with CPP with or without MKRN3 mutations (47.3 and 50%, respectively), followed by a significant reduction after GnRHa treatment. No significant differences in the values of mean FH and target height were found between the 2 CPP groups after GnRHa treatment. Menarche occurred at the expected age in patients with or without CPP due to MKRN3 mutations (11.5 ± 1.3 and 12 ± 0.6 years, respectively). The prevalence of polycystic ovarian syndrome was 9.1% in patients with CPP due to MKRN3 mutations and 5.9% in those with idiopathic CPP.

CONCLUSION

Anthropometric, metabolic, and reproductive outcomes after GnRHa treatment were comparable in CPP patients, with or without MKRN3 mutations, suggesting the absence of deleterious effects of MKRN3 defects in young female adults' life.

Different role of the ventral medial prefrontal cortex on modulation of innate and associative learned fear

Reversible inactivation of the ventral portion of medial prefrontal cortex (vMPFC) of the rat brain has been shown to induce anxiolytic-like effects in animal models based on associative learning. The role of this brain region in situations involving innate fear, however, is still poorly understood, with several contradictory results in the literature. The objective of the present work was to verify in male Wistar rats the effects of vMPFC administration of cobalt chloride (CoCl(2)), a selective inhibitor of synaptic activity, in rats submitted to two models based on innate fear, the elevated plus-maze (EPM) and light-dark box (LDB), comparing the results with those obtained in two models involving associative learning, the contextual fear conditioning (CFC) and Vogel conflict (VCT) tests. The results showed that, whereas CoCl(2) induced anxiolytic-like effects in the CFC and VCT tests, it enhanced anxiety in rats submitted to the EPM and LDB. Together these results indicate that the vMPFC plays an important but complex role in the modulation of defensive-related behaviors, which seems to depend on the nature of the anxiety/fear inducing stimuli.