43. Following breast cancer treatment 25 patients were monitored for plasma levels of the MUC-1 gene product antigen CA-27.29 to determine if high levels of antigen are associated with cancer reoccurence. Anything over 100 U/ml is considered a high level. Calculate the prevalence of reoccurence in our sample. Also calculate the sensitivity, specificity and the positive predictive value using 100U/ml as a cutoff. LO IV.4 Cancer returned 110 Cancer Free 102 84 95 98 52 112 104 89 . 94 115 91 103 94 66 101 85 90 109 92 84: 105 114 75 93 Prevalence = 15 X 100 = 60 % 25 15 Sensitivity = TP Xlou _ TP + FN 15 +6 71. 425 Speafialy = TN x100 $10 X101 68. 90. 90 Y TNT FP 4+ 61 Yrv = TP x100 = 85 X100 = 6893.75 TP + FP