Prognostic Impact of Caspase-8, CDK9 and Phospho-CDK9 (Thr 186) Expression in Patients with Uterine Cervical Cancer Treated with Definitive Chemoradiation and Brachytherapy.

After primary platinum-based chemoradiation of locally advanced uterine cervical cancer, a substantial proportion of women present with persistent, recurrent or metastatic disease, indicating an unmet need for biomarker development. We evaluated the clinical records of 69 cervical cancer patients (Federation of Gynecology and Obstetrics, FIGO Stage > IB3) who were subjected to definitive CRT. Immunohistochemical scoring of caspase-8, cyclin dependent kinase 9 (CDK9) and phosphorylated (phospho-)CDK9 (threonine (Thr) 186) was performed on pretreatment samples and correlated with the histopathological and clinical endpoints, including relapse-free survival (RFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS) and overall survival (OS). Lower levels of caspase-8 were more prevalent in patients with a higher T-stage ( = 0.002) and a higher FIGO stage ( = 0.003), and were significantly correlated with CDK9 expression ( = 0.018) and inversely with pCDK9 detection ( = 0.014). Increased caspase-8 levels corresponded to improved RFS ( = 0.005), DMFS ( = 0.038) and CSS ( = 0.017) in the univariate analyses. Low CDK9 expression was associated with worse RFS ( = 0.008), CSS ( = 0.015) and OS ( = 0.007), but not DMFS ( = 0.083), and remained a significant prognosticator for RFS ( = 0.003) and CSS ( = 0.009) in the multivariate analyses. Furthermore, low pCDK9 staining was significantly associated with superior RFS ( = 0.004) and DMFS ( = 0.001), and increased CSS ( = 0.022), and remained significant for these endpoints in the multivariate analyses. Increased caspase-8 and CDK9 levels correlate with improved disease-related outcomes in cervical cancer patients treated with CRT, whereas elevated pCDK9 levels predict worse survival in this patient population.