The prevalence of CDK12 alterations in Chinese cancer patients and the association with tumor mutation burden(TMB) and survival.

Abstract

e13663 Background: Cyclin-dependent kinase 12 (CDK12) is a cyclin-dependent kinase that regulates transcription and RNA splicing, thereby modulating multiple cellular processes. It has been suggested that CDK12 loss-of-function mutations lead to a higher neoantigen burden and favorable responses to PD-1 inhibitors in advanced prostate cancer. Given this potentially actionable molecular subtype, we sought to determine the prevalence of CDK12 alterations in Chinese cancer patients and the association with TMB and overall survival(OS). Methods: The prevalence of CDK12 alterations were queried in 3D Medicines database with 15,745 Chinese cancer patients involved. Whole-exome sequencing data of 464 patients with prostate adenocarcinoma(PRAD) from the Cancer Genome Altas (TCGA) were downloaded to explore the association between CDK12 gene alteration and OS. And the association with TMB were analyzed in a cohort of 731 patients with various cancer types published by Memorial Sloan Kettering (MSKCC) (Samstein et al., Nature Genetics, 2019). Results: Any CDK12 and known or likely deleterious CDK12 mutations were identified in 598(3.8%) and 98(0.62%) patients, respectively. Across all cancer types, prostate adenocarcinoma(PRAD) was found to have the highest frequency of deleterious mutations(8.75%, 23/263), followed by breast cancer (4.97%, 25/503). Mutations were also detected in multiple cancer types including bladder cancer, ovarian cancer, lung cancer, colorectal cancer and so on with a frequency of less than 1%. CDK12 mutations were associated with shorter OS (HR = 15.25; 95% CI, 2.88-80.73; p < 0.001) in TCGA PRAD and cholangiocarcinoma datasets, which was not seen in other cancer types. Patients harboring CDK12 mutation had a significant higher TMB(p < 0.001) in the pan-cancer study of publicly-available cohort from MSKCC. Conclusions: CDK12 alterations existed across tumor types in Chinese patients with relatively high frequencies detected in PRAD and breast cancer and represent extremely rare events in multiple cancers. CDK12 mutation was a poor prognostic factor in PRAD and cholangiocarcinoma. In a pan cancer analysis patients with CDK12 mutation tended to have a significant higher TMB and may benefit from PD-1/L1 blockade immunotherapy.