Detection of Kita-Kyushu Lung Cancer Antigen-1, a Cancer/Testis Antigen, in the Stomach Close to a Cancerous Condition.

Kita-Kyushu lung cancer antigen-1 (KK-LC-1), encoded by , is a cancer/testis antigen (CTA) and an attractive target for immunotherapy. Our previous study demonstrated frequent expression in gastric cancers (GCs) and non-tumor sites of the stomach with tumors. Additionally, there was a correlation with () infection. Since it currently remains unclear whether KK-LC-1 is expressed in the stomach without GC, this study investigated KK-LC-1 expression in non-GC stomach. We investigated differences in gene expression at non-tumor sites of stomachs with or without tumors in 118 GC patients and 115 non-GC patients. Fisher's exact test was used for statistical analyses. expression was detected in 77% of non-tumor sites in stomachs with tumors, which was significantly higher than in stomachs without tumors (7%, p < 0.0001). All patients with expression at non-tumor sites of their stomachs without tumors carried . appears to be rarely expressed in the atrophic stomach, and furthermore, a part of patients positive for its expression will develop GC in the future, suggesting that expression is a useful marker for predicting GC.