Published online Jan 28, 2020. doi: 10.3748/wjg.v26.i4.424
Peer-review started: November 23, 2019
First decision: December 12,2019
Revised: December 23, 2019
Accepted: January 11, 2020
Article in press: January 11, 2020
Published online: January 28, 2020
The ABCD stratification [(combination of serum pepsinogen (PG) levels and titers of antibody (immunoglobulin G, IgG) against Helicobacter pylori (H. pylori)] is effective for the classification of individuals at risk of developing gastric cancer (GC). The Kita–Kyushu lung cancer antigen-1 (KK-LC-1) is a Cancer/Testis antigen frequently expressed in GC.
To evaluate the effectiveness of KK-LC-1 and ABCD stratification in the diagnosis of GC.
We analyzed the gene expression of KK-LC-1 in surgical specimens obtained from GC tumors. The levels of serum PG I/PG II and IgG against H. pylori were measured. According to their serological status, the patients were classified into the four groups of the ABCD stratification.
Of the 77 examined patients, 63 (81.8%) expressed KK-LC-1. The IgG titers of H. pylori and PG II were significantly higher in patients expressing KK-LC-1 than those measured in patients not expressing KK-LC-1 (P = 0.0289 and P = 0.0041, respectively). The expression of KK-LC-1 in group C [PG method (+)/H. pylori infection (+)] was as high as 93.9% high. KK-LC-1 was also detected in group A [-/-].
The KK-LC-1 expression in GC was associated with H. pylori infection and atrophic status, so that, KK-LC-1 may be a useful marker for the diagnosis of GC.
Core tip: Kita-Kyushu lung cancer antigen-1 (KK-LC-1) is a relatively later cancer-testis antigen and is recently elevated the interest because Stevanovic et al reported in Science 2017 that KK-LC-1 was predominant antigen for cancer immunotherapy. This study investigated that KK-LC-1 expression in gastric cancer (GC) relevant to ABCD stratification and its indexes to indicate the risk of GC appearing. KK-LC-1 expression was correlated with Helicobacter pylori, immunoglobulin G, and pepsinogen II. KK-LC-1 was frequently expressed group C of ABCD stratification, meaning that ABCD stratification would be also useful for GC expressing KK-LC-1, which is the target for cancer immunotherapy.