A. Dot-blot confirms the PCR data in representative MM cell lines on the left (U266, 8226, ARP-1, ARK-B and KMS-11) and patients (negative patients not shown) on the right, in three different serial dilutions (1:100, 1:500, 1:1000). 1) positive ctrl (PTTG-1 20 μg), 2) positive ctrl (PTTG-1 10 μg), 3) negative ctrl (TBS only). The primary antibody was diluted 1:250 (Zymed Lab), secondary antibody 1:5000 (Pierce). B. ELISA technique shows the presence of IgG against PTTG-1 in 12/19 MM patients (63%). The cut-off point (mean + 3 STDEV), based on 11 healthy controls' values, is OD450 nm = 0.404.