From bench to bedside in the sella: translational developments in pituitary tumour genetics

The two most prevalent pituitary tumour types are pituitary adenomas (also referred to as pituitary neuroendocrine tumours or pitNETs) and craniopharyngiomas, collectively accounting for 98% of all pituitary tumours. The genetic basis of these pituitary tumours is partly understood. In pituitary adenomas, established predisposition genes in the germline setting are MEN1, PRKAR1A, AIP, CDKN1B, GPR101 and the SDHx genes, while somatic driver mutations are well described in GNAS in somatotrophinomas and in USP8 in corticotrophinomas. Craniopharyngiomas are not heritable tumours, but there is a clear genetic basis at the somatic level, with clonal CTNNB1 and BRAF variants present in approximately 95% of adamantinomatous and papillary craniopharyngiomas, respectively. This review explores mechanistic developments in these established genes, new genes in the pituitary adenoma setting (e.g. MAX, CABLES1, CDH23, PAM or CHEK2), and emerging uses of CTNNB1/BRAF testing in the craniopharyngioma setting. It concludes with a discussion of the bench-to-bedside translations of these scientific discoveries as they pertain to clinicians seeing patients with these sellar tumours. In current clinical practice, the most readily applicable and directly impactful translations of recent pituitary genetic research are the opportunities for germline DNA testing for familial pituitary tumour syndromes and tumour DNA testing of craniopharyngiomas to confirm diagnosis (adamantinomatous/papillary craniopharyngioma) and guide treatment (in papillary craniopharyngioma).