<prompt> Which of the following cell types secretes prostate specific antigen PSA?Benign prostate epithelial cells onlyMalignant prostate epithelial cells onlyBenign and malignant prostate epithelial cellsProstate stromal cells  <response>: Prostate-specific antigen PSA, a glycoprotein with a MW of 34,000, is a biological marker used in the detection of prostate cancer. It is secreted from prostatic epithelial cells and is responsible for aiding liquefaction of semen. This marker, which is evaluated with a blood test, can be produced by both benign and malignant epithelial cells. The prostate stromal cells do not produce PSA. Ref:Barrett K.E., Barman S.M., Boitano S., Brooks H.L. 2012. Chapter 23. Function of the Male Reproductive System. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks Eds, Ganongs Review of Medical Physiology, 24e. 