WFDC2 and lung adenocarcinoma: Additionally, patients with lung adenocarcinoma demonstrated significantly higher levels of HE-4 than those with squamous cell carcinoma and small cell carcinoma.[27] In another study conducted in 88 patients with different types of PE by Elsammak et al, both serum HE-4 levels and HE-4 levels of PE were detected to be significantly higher in the patients with lung and extrapulmonary malignant effusions than those with transudative or nonmalignant exudative effusion.