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. Here, WFDC2 is linked to squamous cell carcinoma.