Serum Analysis of Women with Early-Stage Breast Cancer Using a Mini-Array of Tumor-Associated Antigens.

Background: Several studies have shown that patients with cancer have antibodies in serum that react with cellular autoantigens, known as Tumor-Associated Antigens (TAA). The present work aimed to determine whether a mini-array comprising four recombinant TAA increases the detection of specific serum antibodies for the diagnosis of early-stage breast cancer. Methods: The mini-array included Alpha 1-AntiTrypsin (A1AT), TriosePhosphate Isomerase 1 (TPI1), Peptidyl-Prolyl cis-trans Isomerase A (PPIA), and PeroxiReDoXin 2 (PRDX2) full-length recombinant proteins. The proteins were produced after gene cloning, expression, and purification, and were verified by Western blot assays. Then, Dot-Blot was performed to find antibodies against the four TAA in 12 sera from women with early-stage breast cancer (stage II) and 12 sera from healthy women. Results: Antibody detection against individual TAA in early-stage breast cancer sera ranged from 58.3% to 83.3%. However, evaluation of the four TAA showed that there was a positive antibody reaction reaching a sensitivity of 100% and a specificity of 85% in early-stage breast cancer, suggesting that this mini-array must be evaluated as a clinical diagnostic tool for early-stage breast cancer in a larger sample size. Conclusion: Our results suggest that TAA mini-arrays may provide a promising and powerful method for improving the detection of breast cancer in Mexican women.

Differential effect of multiple kinesin motors on run length, force and microtubule binding rate.

The in vitro transport of cargo by motor proteins constitutes a model system to understand mechanisms of vesicle trafficking inside cells. Here we apply the classic bead assay with a short, stiff kinesin protein to test the effect of multiple motors on essential transport parameters: distance, force and microtubule binding rate. Measurements of unloaded run length show that the transition from single- to multiple-motor behavior can be characterized by the appearance of extended runs, in accordance with a recently proposed model that quantifies the probability of multiple-motor engagement. In this transition, application of mechanical load using optical tweezers allows us to register maximum force values above single kinesin levels (8 pN). Yet, averages of run length and maximum force undergo little change as the probability of multiple-motor participation increases. In contrast, the measured rate of bead binding to microtubules scales linearly with the average number of motors per bead. These observations suggest that multiple motors bound randomly to the same cargo mainly increase the probability of attachment of these cargoes to the cytoskeletal filament network.