Xiao and other scholars studied the lung tissue and tumor markers in serum HE4 expression levels and its role in the differential diagnosis of lung cancer, the experiment tested the 214 cases of lung cancer patients and 76 cases of healthy human lung adenocarcinoma, lung squamous carcinoma, and adjacent tissues in the expression of HE4, and results show that the HE4 as a biomarker of lung cancer, for the early diagnosis of lung cancer, can provide important reference [25]. The gene discussed is WFDC2; the disease is neoplasm.