Detection of Kita-Kyushu Lung Cancer Antigen-1, a Cancer/testis Antigen, in the stomach closer to the cancerous condition.

Background: Kita-Kyushu lung cancer antigen-1 (KK-LC-1) is a cancer/testis antigen (CTA) and is an attractive target for immunotherapy. An earlier study from our group demonstrated frequent KK-LC-1 expression in gastric cancers (GC) and non-tumor sites of the stomach carrying a tumor. Additionally, there was a correlation to Helicobacter pylori (Hp) infection. Currently it remains unclear whether KK-LC-1 is expressed in stomachs without gastric cancer.Methods: In the present study, we investigated differences in KK-LC-1 gene expression at non-tumor sites of stomachs with or without a tumor from 118 GC patients and 115 non-GC patients. Fisher’s exact test was used for the statistical analyses.Results: Our results show that KK-LC-1 gene expression was detected in 77% of non-tumor sites in stomachs with a tumor. Such findings were significantly higher than in stomachs without a tumor (7%, P <0.0001). All patients with KK-LC-1 expression at non-tumor sites of their stomachs without tumors carried Hp.Conclusions: KK-LC-1 appears to be detected in the stomach’s precancerous condition, but not in an atrophic stomach with Hp. KK-LC-1 may be a useful marker for gastric cancer prediction.