Role of complement activation product C4d as a predictor biomarker in lung cancer diagnosis: a case–control study

Abstract

Background Molecular biomarkers such as complement C4d in bronchoalveolar lavage (BAL) may interfere with lung cancer diagnosis. However, limited studies have been conducted. The authors aimed to study the role of complement C4d as a predictive marker for lung cancer diagnosis. Participants and methods This case–control study included 45 participants: 30 were diagnosed as patients with lung cancer, comprising 16 with non-small cell lung cancer (NSCLC) and 14 with small cell lung cancer (SCLC), and 15 apparently healthy individuals as a control group. All patients (group I) were subjected to chest radiography, chest computed tomography, and flexible bronchoscopy. Forceps biopsies and BAL were taken for histopathological and cytological examination and measurement of C4d levels. For all participants, sputum and blood samples were collected for C4d measurement. Results There were statistically significant higher complement C4d levels in serum (P=0.006) and sputum of patients with lung cancer versus control group (P<0.001). There was no statistically significant difference in complement C4d level between NSCLC and SCLC in the three samples (P=0.315 for BAL, 0.7 for serum, and 0.744 for sputum). Complement C4d has a high sensitivity and specificity in serum and BAL for lung cancer prediction. Conclusion Complement activation product C4d biomarker could be used as a predictor of lung cancer diagnosis; however, it cannot differentiate between its two major subtypes: NSCLC and NSCLC.

Keywords

• bronchoalveolar lavage
• c4d
• complement
• lung cancer