Well-known secreted proteins, such as CA125, CEA, CA199, AFP and PSA, are biomarkers for monitoring cancer recurrence or metastasis in clinical settings, and proteins in the culture supernatant reportedly reflect the biological behavior of tumor cells in vivo;24 thus, the analysis of proteins secreted by stromal macrophages may help identify potential diagnostic and prognostic cancer biomarkers. The gene discussed is AFP; the disease is cancer.