Establishment of an Esophageal Squamous Cell Carcinoma Tumor Line and Development of Serum Squamous Cell Carcinoma-related Antigen in Athymic Nude Mice

A serially transplantable tumor line (IMEs-1) derived from human esophageal squamous cell carcinoma (SCC) of a 71-year-old female was established in nude mice. The histology of IMEs-1 closely resembled that of the original tumor and tumor doubling time was 3.2 days. Production of SCC-related antigen (SCCRA) and carcinoembryonic antigen (CEA) in the serum of tumor-bearing mice was observed. To evaluate the usefulness of SCCRA for esophageal cancer, the relationship between the serum levels of SCCRA and tumor burden in athymic nude mice bearing IMEs-1 was studied. The mean serum levels of SCCRA, as determined by radioimmunoassay, gradually rose in direct proportion to the tumor growth gauged by tumor volume. However, the serum levels of CEA did not increase until the last few weeks of the assay. These results suggest the possibility of using SCCRA as a tumor marker for esophageal SCC. In addition, this nude mouse assay system will provide a theoretical model to study the usefulness of SCCRA.