ECE2024 Poster Presentations Adrenal and Cardiovascular Endocrinology (95 abstracts)
Role of ccfDNA-based biomarkers in classification of adrenocortical adenomas
Mengjie Xu 1,2 , David S Tourigny 3 , Juliane Lippert 4 , Ana Crastin 1 , Silke Appenzeller 5 , Miriam Felicitas Asia 6 , Oskar Podstawka 1 , Yasir Elhassan 6 , Kassiani Skordilis 7 , Alessandro Prete 1 & Cristina L Ronchi 1
1University of Birmingham, Institute of Metabolism and System Research, Birmingham, UK; 2Taihe Hospital, Hubei University of Medicine, Department of Endocrinology, Shiyan, China; 3University of Birmingham, School of Mathematics, Birmingham, UK; 4University of Wuerzburg, Institute of Human Genetics, Wuerzburg, Germany; 5University Hospital of Wuerzburg, Core Unit Bioinformatics, Comprehensive Cancer Center Mainfranken, Wuerzburg, Germany; 6Queen Elizabeth Hospital Birmingham NHS Trust, Department of Endocrinology, Birmingham, UK; 7Queen Elizabeth Hospital Birmingham NHS Trust, Department of Renal Histopathology, Birmingham, UK
Background: Adrenocortical adenomas (ACA) can be associated with different degrees of cortisol excess. Genetic alterations in the cAMP/PKA pathway are observed in up to 60% of cases with overt Cushing syndrome (CS-ACA) and 15% of cases with mild autonomous cortisol secretion (MACS-ACA), while variants in the gene coding for β-catenin (CTNNB1) are more frequent in MACS-ACA and non-functioning adrenal tumours (NFAT). We aimed to test whether somatic variants could be detected in circulating cell-free DNA (ccfDNA) from patients with adrenal CS or MACS and potentially contribute to management strategies.
Methods: We investigated 44 patients, including 17 with MACS-ACA, 9 with CS-ACA, 12 with aldosterone-producing adenomas (APA), and 6 with NFAT. A total of 23 healthy subjects (HS) were used as controls. ccfDNA was extracted from EDTA blood samples with commercially available kits and ccfDNA concentrations quantified with fluorimeter. Tumour-DNA (T-DNA) was isolated from paraffin embedded tissue samples in 14/44 cases. Matched ccfDNA/T-DNA were sequenced using a customized panel including 32 genes (Cell3™ Target by Informed Genomics) and Illumina platform. Leucocyte DNA was used to filter out germline variants using TNhyplotyper2 (Sentieon) with an additional orientation bias model to remove strand bias artefacts. Only variant candidates that passed stringent filters were retained (read depth greater than 10, variant allele frequency greater than 0.1 in ccfDNA/T-DNA and less than 0.02 in paired leucocyte DNA).
Results: Patients with ACA had higher total ccfDNA concentrations than HS (0.155±0.147 vs 0.052±0.048 ng/μl, P<0.001), with CS-ACA showing the highest ccfDNA levels (0.267±0.143 ng/μl, P<0.005 vs HS). ccfDNA concentrations did not correlate with age, sex, and maximum tumor diameter, but there was a trend toward a positive correlation with cortisol levels after overnight dexamethasone suppression test (P=0.0641, R=0.29). At T-DNA level, somatic variants were identified in 50% of ACA (i.e., PRKACA in 2/6 CS-ACA, CTNNB1 in 2/4 MACS-ACA and 1/6 CS-ACA, and KCNJ5 in 2/4 APA). Somatic mutations were not detected in any of the investigated ccfDNA samples.
Conclusions: Total ccfDNA concentrations are higher in patients with adrenal CS, likely due to an impact of the excessive circulating cortisol levels. Despite the presence of somatic variants in 50% of tumor samples from our ACA cohort, we did not detect any at ccfDNA level. Therefore, this approach appears ineffective for pre-operative evaluation of genetic alterations and clinical decision making.
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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