Intraoperative immunostaining for detection of invasive cells at the resection margin of Borrmann type 4 gastric carcinoma using monoclonal antibody S202.

Borrmann type 4 gastric cancer is clinically characterized by diffuse infiltration with carcinoma cells. An antiscirrhous carcinoma monoclonal antibody (MAb) S202 was used in a rapid immunostaining procedure to identify the limit of tumour invasion during surgery in samples obtained from the resection margins in 37 cases of Borrmann type 4 gastric cancer. In two instances, conventional cytological diagnosis using haematoxylin and eosin staining was negative, and in another it was inconclusive; whereas by the rapid immunostaining method single cells stained darkly, indicating malignancy. In two specimens, a positive diagnosis could be made by both methods, but immunostaining of these sections served to highlight the adenocarcinoma cells against the inflammatory background: further resection was performed. This technique enables clear recognition of the infiltrating tumour cells in the frozen sections of resected specimens. The rapid immunostaining method using MAb S202 allowed accurate and rapid determination of the limit of tumour extension at the surgical margin during surgery.