Relationship between Kita-Kyushu Lung Cancer antigen-1 expression and prognosis of cases with lung squamous cell carcinoma.

BACKGROUND: Previously, we identified the highly immunogenic cancer testicular antigen named Kita-Kyushu Lung Cancer antigen-1 (KK-LC-1). In this study, we analyzed the effect of KK-LC-1 expression on the prognosis of patients with resected squamous cell lung cancer. METHODS: Fifty squamous cell lung cancer patients, who received complete resection, were enrolled in this study. The expressions of KK-LC-1, CD8, human leukocyte antigen (HLA) class I, and programmed cell death protein ligand-1 (PD-L1) were assessed via immunohistochemistry staining using the specimens obtained from the participants. The association between the expression of the abovementioned molecules and patient prognosis was investigated. RESULTS: KK-LC-1 expression was observed in 21 of 50 recruited cases (42%). However, no significant correlation was found between KK-LC-1 expression and patient prognosis. The prognosis was significantly better in lung cancer cases with KK-LC-1 expression in which CD8+ T cells infiltrated the tumor. Regardless of the HLA class I expression or the PD-L1 expression, the KK-LC-1 expression in squamous cell lung cancer could not be detected as a significant prognostic factor. Furthermore, considering the polarity of the cancer tissue as epithelium, staining of KK-LC-1 tended to be strong in the area corresponding to the basal side of the tumor tissue. The Ki-67 expression was frequently observed in cancer cells on the basal side, which was consistent with the KK-LC-1 expression in representative four cases with KK-LC-1-positive squamous cell lung cancer. CONCLUSIONS: Our results indicated that lung squamous cell cancer patients with KK-LC-1 expression and the tumor infiltrating CD8+ T cells might exhibit better prognosis. KK-LC-1 might be highly expressed in cancer cells with high proliferative capacity. Larger cohort analysis is still required for further elucidation and validation of the results of this study.

Cancer/testis antigen, Kita-Kyushu lung cancer antigen-1 and ABCD stratification for diagnosing gastric cancers.

BACKGROUND: 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. AIM: To evaluate the effectiveness of KK-LC-1 and ABCD stratification in the diagnosis of GC. METHODS: 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. RESULTS: 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 [-/-]. CONCLUSION: 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.

Expression of Kita-Kyushu Lung Cancer Antigen-1 as Detected by a Novel Monoclonal Antibody in Gastric Cancer.

BACKGROUND/AIM: Kita-Kyushu lung cancer antigen-1 (KK-LC-1) is a known cancer/testis antigen. Our group has previously shown KK-LC-1 gene expression in gastric cancer. However, could not be detected the KK-LC-1 protein due to the lack of an appropriate antibody. Here, we assessed our original monoclonal antibody (Kmab34B3) and, using it, assessed the expression of KK-LC-1 in gastric cancer. PATIENTS AND METHODS: We evaluated an original monoclonal antibody against KK-LC-1 (Kmab34B3), and used this antibody to compare KK-LC-1 protein expression in tumour and non-tumour stomach cells from gastric cancer patients. RESULTS: Kmab34B3 stained testicular germ cells, and tumour cells in nine out of 11 (82%) specimens. In non-tumorous areas, Kmab34B3 stained 13 out of 29 (45%) pyloric gland specimens. Furthermore, Kmab34B3 also stained intestinal metaplasia positive and negative areas. CONCLUSION: Kmab34B3 was able to detect KK-LC-1 protein within tumour cells and the pyloric gland where the gene has been shown to be expressed. Therefore, it might be an attractive tool for detecting KK-LC-1 expression in precancerous and cancerous stomach cells.