Rapid multiple immunocytochemical staining method using microwave irradiation for intraoperative cytology.

Objective: To develop a more rapid and accurate staining procedure for intraoperative cytology through an assessment of a rapid multiple immunocytochemical staining method using microwave irradiation.

Study Design: A preliminary test of a triple immunostaining method using microwave irradiation was performed to determine optimal incubating conditions for primary antibodies against MOC-31, BerEP4 and carcinoembryonic antigen. The test samples were adenocarcinoma cells obtained by washings from 10 resected colorectal cancer specimens. Adenocarcinoma cells in peritoneal washings diagnosed by cytologic examination from 8 colorectal cancer patients were retrospectively examined using the previously determined optimal incubating conditions.

Results: High rates of positive cells (83-87%) with intense immunoreactions were obtained using a rapid process with primary antibody concentrations that were 2 times higher than those used for standard incubation at room temperature (82-86%). The staining under these conditions was completed within 19 minutes. Adenocarcinoma cells in the peritoneal washings were also intensely stained under these conditions.

Conclusion: Using our microwave method, the processing time was dramatically shortened, and intense and sensitive immunoreactions were obtained. The present method is useful for the rapid and accurate diagnosis of intraoperative cytology.