PROS1 and cancer: Since increased APC resistance in cancer has been detected in several previous studies, adjustments were made for the hemostatic parameters that correlated to APC resistance; protein C (ρ = -0.18, P = 0.003), protein S (ρ = -0.33, P < 0.001), and free TFPI (ρ = -0.42, P < 0.001).