Abstract IA025: The cell of origin is the dominant constraint in evolution of VHL related neoplasms

Cancer is an evolutionary process, and an evolutionary framework can be used to decipher cancer initiation, progression and treatment resistance. In the context of VHL disease with repeat evolution of malignancies across different tissue contexts we can examine the factors that constrain tumour evolution. In the largest analysis of VHL-related tumours to date (1321 tumours across 132 patients), we observe the second hits on the background of germline VHL mutation vary and include loss of chromosome 3p, narrow deletion of VHL locus, VHL mutation or methylation. Pheochromocytomas and paragangliomas (PPGL) and solid renal tumours show a higher frequency of 3p loss, while pancreatic neuroendocrine tumors (PNETs) and renal cysts, exhibited a higher frequency of somatic VHL mutations, without 3p loss. Tumour size and progression were contingent on the nature of the second hit, suggesting potential evolutionary "dead-ends" where the tumor initiating event does not involve 3p loss. The type of germline VHL mutation (whether a complete deletion or missense) determined the distribution of cancers and their burden, but beyond this, multiple renal tumours in individual patients did not converge onto the same trajectory. This observation suggests that following malignant transformation evolutionary contingency and chance dominate tumour evolution. Metastases from renal tumours were driven by loss of chromosomes 9p and 14q, reminiscent of sporadic renal tumours, suggesting that acquisition of metastatic competence is associated with a high degree of bottlenecking and highlighting these events as important targets for metastasis prevention. Citation Format: Scott Shepherd, Alex Coulton, Cathy Vocke, Chris Ricketts, Marston Linehan, Samra Turajlic. The cell of origin is the dominant constraint in evolution of VHL related neoplasms [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr IA025.