KLK3 and Familial prostate cancer: Other multi-marker test protocols, the ProstAsure index (Babaian et al 1998) and ProstataClass (Stephan et al 2002a, b), use neural network-derived, non-linear algorithms to calculate the risk for prostate cancer from values for three serum markers and the patient’s age (ProstAsure), or free and total PSA, DRE, patient age and prostate volume (ProstataClass).