WFDC2 and breast cancer: In recent studies, HE4 has been shown to be a potential biomarker for ovarian cancer, lung adenocarcinoma, endometrial cancer, mesothelioma, transitional cell cancers, and breast cancer.9-15 In a study, it was stated that HE4 has high sensitivity alone as a marker in the diagnosis of early-stage ovarian cancer, while CA125/HE4 combination has increased sensitivity compared to CA125 alone or HE4 alone.30 Human Epididymitis Protein 4 was approved by the US Food and Drug Administration as a serum tumor marker in ovarian carcinomas in 2003.31