Characterizing cyclin-dependent kinase 12(CDK12)-altered aggressive prostate cancer: a twelve-case series

Background: Prostate cancer harboring cyclin-dependent kinase 12 (CDK12) abnormalities is a hot topic due to its distinctive clinical features, such as sensitivity to immune checkpoint inhibitors. In the last few years, precision medicine using comprehensive genome sequencing has become familiar, and the era of precision oncology has arrived in the field of prostate cancer. This study aimed to present the demographic characteristics of patients with CDK12 alterations. Methods: In 12 patients with detected CDK12 alterations in our hospital between 2015 and 2021, we evaluated their genomic features and clinical course. CDK12 allelic status was classified into three groups: monoallelic loss, potentially biallelic loss, and biallelic loss based on the genome analyses. Results: Seven patients already had metastatic cancer at the time of diagnosis, and all 12 patients had Gleason grade ≥ 4. Most cases of biallelic loss or potentially biallelic loss were metastatic cancers at the initial staging, and all these cases were categorized into Gleason grade 5. Two of the 12 patients had BRCA2/RB1 co-loss, and the other two had whole genome duplication. Five patients had a long-term survival of > 6 years, but two patients died within 4 years of diagnosis. Conclusion: This is the first Japanese prostate cancer case series with CDK12 alterations. CDK12-altered prostate cancer is a heterogeneous disease, and accumulating cases with detailed information leads to precision oncology.