Objective To detect the expression level of interleukin-34 (IL-34) in lung adenocarcinoma (LUAD) with epidermal growth factor receptor (EGFR) mutant and to investigate the relationship between IL-34 and prognosis in these patients.

Methods A total of 144 LUAD patients with EGFR mutant were enrolled, who had not received any chemotherapy, immunotherapy or radiotherapy before surgery and underwent resection from July 2015 to December 2017 in Zhongshan Hospital, Fudan University. The immunohistochemistry (IHC) was uesd to detect the expression of IL-34 in tumor and paired normal lung tissues. Kaplan-Meier curve and Cox model were used to analyze the association of IL-34 with the prognosis of patients.

Results Compared with paired normal tissues, IL-34 was overexpressed in tumor tissues in LUAD patients. The follow-up time was 64(42, 73) months. Kaplan-Meier curve showed that the patients in high IL-34 group (n＝93) had lower overall survival rate (P＝0.006) and higher accumulation recurrence rate (P＝0.011) than the patients in the low IL-34 group (n＝51). Cox model analysis showed that IL-34 expression was an independent predictor of overall survival (HR＝2.218, P＝0.015) and recurrence (HR＝2.486, P＝0.018) of patients.

Conclusion IL-34 could be used to predict prognosis of LUAD patients with EGFR mutation.