Prognostic model based on circular RNA circPDK1 for resected lung squamous cell carcinoma

Xiao Sun, Maolong Wang, Rongjian Xu, Dongyang Zhang, Ao Liu, Yuanyong Wang, Tong Lu, Yanlu Xin, Yandong Zhao, Yunpeng Xuan, Tong Qiu, Hao Wang, Shicheng Li, Yang Wo, Dahai Liu, Jinpeng Zhao, Bo Fu, Yaliang Lan, Yudong Han, Wenjie Jiao


Background: Circular RNA has been revealed as a potential biomarker in multiple malignancies. However, few studies have focused on its potential to be prognostic markers in lung squamous cell carcinoma (LSCC). In this work, we aimed to build a prognostic model of resected LSCC based on circular RNA pyruvate dehydrogenase kinase 1 (circPDK1) and other clinicopathological factors.
Methods: circPDK1 was identified via next-generation sequencing. Three hundred two cases of LSCC tissue and their adjacent normal lung tissues were obtained from multiple medical centers and divided into study cohort (n=232) and validation cohort (n=70). The expression of circPDK1 was detected for analyzing its potential prognostic value for recurrence-free survival (RFS) and overall survival (OS) in LSCC. Finally, combined with circPDK1, T staging, lymph nodes (LN) metastasis status, age, and serum Squamous Cell Carcinoma Antigen (SCCAg), we built a prognostic model by nomograms method and confirmed it in the validation cohort.
Results: CircPDK1 was identified to be overexpressed (P<0.01) in LSCC. Through analysis in study cohort, circPDK1low patients (less than the mean expression, n=124) showed more lymph nodes metastasis (P=0.025), more vascular invasion (VI) (P=0.047), more visceral pleural invasion (VPI) (P=0.015) and poorer prognosis (P=0.003) than circPDK1high ones (n=108). Univariate and multivariate analysis showed that circPDK1, T staging, LN status, age, and SCCAg were significant prognostic factors for RFS and OS. The prognostic model based on these factors showed the concordance index (C-index) of 0.8214 and 0.8359 for predicting 5-year RFS and OS, respectively. Finally, the calibration curves were performed in the study cohort and a validation cohort to evaluate the model’s efficiency.
Conclusions: circPDK1 was identified as a potential biomarker of resected LSCC. The prognostic model including circPDK1, T staging, LN status, age, and SCCAg could effectively predict prognosis of resected LSCC.