Figure 4. Humoral responses against AKAP4 in ovarian carcinoma patients. (A) Figure Humoral responses against AKAP4 in ovarian cancer specimens obtained from Stage I, Stage II, Stage III and Stage IV patients. X represents the cut-off value (calculated as the mean of antibody titers detected in healthy donors + 2SD) above which all specimens were considered as positive. (B) Immunoblotting experiments were performed to confirm anti-AKAP4 humoral responses and the specificity of circulating anti-AKAP4 antibodies was validated by neutralization experiments. Lane 1, coomassie brilliant blue stained purified recombinant AKAP4 protein; Lane 2, polyclonal anti-AKAP4 antibody showing AKAP4 immunoreactivity; Lane 3–6, AKAP4-immunoreactive bands indicative of AKAP-specific humoral responses in representative stage I, stage II, stage III and stage IV patients; Lane 7, absence of anti-AKAP4 humoral responses in the serum of a healthy donor; Lane 8, absence of AKAP4-immunoreactive bands upon the pre-incubation of the patient's serum with 15 μg/mL recombinant AKAP4.