Epidermal growth factor receptor ectodomain in the urine of patients with squamous cell carcinoma

In this study we determined the levels of the epidermal growth factor receptor (EGFR) in the urine of patients with squamous cell carcinoma compared to levels in the urine of normal volunteers and patients with nonsquamous cell carcinoma. A 24-h urine specimen was collected from 50 normal volunteers, 50 patients with nonsquamous cell carcinoma, and 42 patients with squamous cell carcinoma. An ELISA using mAbs to the external domain of the EGFR was used to measure levels of the receptor in the urine samples. Measurement of the EGFR ectodomain in the 24-h urine specimens showed detectable levels in 15 (36%) of 42 squamous cell carcinoma patients compared to 3 (6%) of 50 controls and 8 (16%) of 50 nonsquamous patients. It was also observed that 10 (53%) of 19 patients with metastatic squamous cell carcinoma had detectable EGFR ectodomain levels compared to 5 (22%) of 23 squamous cell patients with localized disease. Thus, we concluded that the EGFR ectodomain was detectable in the urine in a significantly higher number of patients with squamous cell carcinoma than normal volunteers or patients with nonsquamous cell carcinoma.