Incidentaloma risk factors
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohammed Abdelwahed M.D[2]
Overview
Most adrenocortical carcinomas are sporadic, but some occur as a component of hereditary cancer syndromes such as Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, and Multiple endocrine neoplasia type 1(MEN1). Genetic basis of sporadic incidentaloma includes TP53 gene. A role for the TP53 tumor suppressor gene in sporadic ACCs is suggested by the frequent finding of loss of heterozygosity (LOH) at the 17p13 locus in sporadic ACCs. Another chromosomal locus that is strongly implicated in the pathogenesis of ACC is 11p, the area of abnormality in Beckwith-Wiedemann syndrome and the site of the insulin-like growth factor-2 (IGF-2) gene.
Risk Factors
Most adrenocortical carcinomas are sporadic, but some occur as a component of hereditary cancer syndromes.[1]
- Hereditary cancer syndromes:
- Li-Fraumeni syndrome: breast cancer, soft tissue and bone sarcoma, brain tumors, associated with inactivating mutations of the TP53 tumor suppressor gene on chromosome 17p.
- Beckwith-Wiedemann syndrome: Wilms' tumor, neuroblastoma, hepatoblastoma, associated with abnormalities in 11p15
- Multiple endocrine neoplasia type 1 (MEN1) (parathyroid, pituitary, and pancreatic neuroendocrine tumors and adrenal adenomas, as well as carcinomas, associated with inactivating mutations in the MEN1 gene on chromosome 11q.[2]
Genetic basis of risk factors
Sporadic cases genetics
- TP53 gene, located on chromosome 17p13, is the most frequently mutated gene in human cancers. A role for the TP53 tumor suppressor gene in sporadic ACCs is suggested by the frequent finding of loss of heterozygosity (LOH) at the 17p13 locus in sporadic ACCs.[11]
- Although the loss of heterozygosity at 17p13 is common, only approximately one-third of these tumors have a mutation of TP53. This suggests that another as yet unidentified suppressor gene is present in this locus.[3]
- Another chromosomal locus that is strongly implicated in the pathogenesis of ACC is 11p, the area of abnormality in Beckwith-Wiedemann syndrome and the site of the insulin-like growth factor-2 (IGF-2) gene. LOH at the 11p15 locus and overexpression of IGF-2 have been associated with the malignant phenotype in sporadic ACCs.[13] However, other growth-related tumor suppressor genes at this locus may also be involved.
- Most adrenocortical tumors are monoclonal, suggesting that they result from accumulated genetic abnormalities, such as activation of proto-oncogenes and inactivation of tumor suppressor genes.[4]
Beta-catenin mutations (CTNNB1)
- Constitutive activation of beta-catenin in the Wnt signaling pathway has been identified as a frequent alteration in benign and malignant adrenocortical tumors.[5]
- The increased occurrence of adrenal tumors in patients with mutations of adenomatous polyposis coli (APC) suggested that the Wnt/beta-catenin pathway could be involved in adrenal tumorigenesis.[6]
- This pathway is essential for embryonic development of the adrenal, and its ectopic constitutive activation is associated with cancer development in a number of tissues.[7]
Aberrant receptors
- Cortisol hypersecretion is the most frequent hormonal abnormality detected in patients with functioning unilateral adrenal adenomas. It had been assumed that the mechanism for this was non-ACTH-dependent autonomous cortisol secretion from the adenoma.
Somatic mutations of protein kinase A (PKA) catalytic subunit (PRKACA) were identified in patients with overt Cushing's syndrome but not in adenomas secreting less cortisol.
- In additional reports, the same mutation was found in over 50 percent of patients with Cushing's syndrome due to adrenal adenomas.[8]
- The most frequent hotspot p.Leu206Arg mutation is located in the active cleft of the catalytic subunit, inactivating the site where the regulatory subunit RII-beta usually binds, thus causing a constitutive PKA activation.[9]
Mutations in aldosterone-producing adenomas (APA)
- The most frequent causes of primary aldosteronism include bilateral idiopathic hyperplasia and unilateral aldosterone-producing adenoma.[10]
- Somatic mutations in KCNJ5 have been identified in patients with primary aldosteronism due to APA.
- These mutations are more common in women than men; APAs with KCNJ5 mutations are larger than those without mutations.
- Somatic mutations in other important genes implicated in the regulation of aldosterone synthesis (ATP1A1, ATP2B3, CACNA1D, CTNNB1, ARMC5) have also been identified.
References
- ↑ Sidhu S, Sywak M, Robinson B, Delbridge L (2004). "Adrenocortical cancer: recent clinical and molecular advances". Curr Opin Oncol. 16 (1): 13–8. PMID 14685087.
- ↑ Lynch HT, Radford B, Lynch JF (1990). "SBLA syndrome revisited". Oncology. 47 (1): 75–9. PMID 2300390.
- ↑ Libè R, Groussin L, Tissier F, Elie C, René-Corail F, Fratticci A; et al. (2007). "Somatic TP53 mutations are relatively rare among adrenocortical cancers with the frequent 17p13 loss of heterozygosity". Clin Cancer Res. 13 (3): 844–50. doi:10.1158/1078-0432.CCR-06-2085. PMID 17289876.
- ↑ Bourcigaux N, Gaston V, Logié A, Bertagna X, Le Bouc Y, Gicquel C (2000). "High expression of cyclin E and G1 CDK and loss of function of p57KIP2 are involved in proliferation of malignant sporadic adrenocortical tumors". J Clin Endocrinol Metab. 85 (1): 322–30. doi:10.1210/jcem.85.1.6303. PMID 10634406.
- ↑ Mazzuco TL, Durand J, Chapman A, Crespigio J, Bourdeau I (2012). "Genetic aspects of adrenocortical tumours and hyperplasias". Clin Endocrinol (Oxf). 77 (1): 1–10. doi:10.1111/j.1365-2265.2012.04403.x. PMID 22471738.
- ↑ Smith TG, Clark SK, Katz DE, Reznek RH, Phillips RK (2000). "Adrenal masses are associated with familial adenomatous polyposis". Dis Colon Rectum. 43 (12): 1739–42. PMID 11156460.
- ↑ Kikuchi A (2003). "Tumor formation by genetic mutations in the components of the Wnt signaling pathway". Cancer Sci. 94 (3): 225–9. PMID 12824913.
- ↑ Beuschlein F, Fassnacht M, Assié G, Calebiro D, Stratakis CA, Osswald A; et al. (2014). "Constitutive activation of PKA catalytic subunit in adrenal Cushing's syndrome". N Engl J Med. 370 (11): 1019–28. doi:10.1056/NEJMoa1310359. PMC 4727447. PMID 24571724.
- ↑ Ronchi CL, Di Dalmazi G, Faillot S, Sbiera S, Assié G, Weigand I; et al. (2016). "Genetic Landscape of Sporadic Unilateral Adrenocortical Adenomas Without PRKACA p.Leu206Arg Mutation". J Clin Endocrinol Metab. 101 (9): 3526–38. doi:10.1210/jc.2016-1586. PMID 27389594.
- ↑ Monticone S, Castellano I, Versace K, Lucatello B, Veglio F, Gomez-Sanchez CE; et al. (2015). "Immunohistochemical, genetic and clinical characterization of sporadic aldosterone-producing adenomas". Mol Cell Endocrinol. 411: 146–54. doi:10.1016/j.mce.2015.04.022. PMC 4474471. PMID 25958045.