Published online Dec 14, 2017. doi: 10.3748/wjg.v23.i46.8200
Peer-review started: October 6, 2017
First decision: October 18, 2017
Revised: October 30, 2017
Accepted: November 14, 2017
Article in press: November 14, 2017
Published online: December 14, 2017
Processing time: 68 Days and 1.3 Hours
To assess cancer-testis antigens (CTAs) expression in gastric cancer patients and examined their associations with clinicopathological factors.
Eighty-three gastric cancer patients were evaluated in this study. Gastric cancer specimens were evaluated for the gene expression of CTAs, Kitakyushu lung cancer antigen-1 (KK-LC-1), melanoma antigen (MAGE)-A1, MAGE-A3 and New York esophageal cancer-1 (NY-ESO-1), by reverse transcription PCR. Clinicopathological background information, such as gender, age, tumor size, macroscopic type, tumor histology, depth of invasion, lymph node metastasis, lymphatic invasion, venous invasion, and pathological stage, was obtained. Statistical comparisons between the expression of each CTA and each clinicopathological background were performed using the χ2 test.
The expression rates of KK-LC-1, MAGE-A1, MAGE-A3, and NY-ESO-1 were 79.5%, 32.5%, 39.8%, and 15.7%, respectively. In early stage gastric cancer specimens, the expression of KK-LC-1 was 79.4%, which is comparable to the 79.6% observed in advanced stage specimens. The expression of KK-LC-1 was not significantly associated with clinicopathological factors, while there were considerable differences in the expression rates of MAGE-A1 and MAGE-A3 with vs without lymphatic invasion (MAGE-A1, 39.3% vs 13.6%, P = 0.034; MAGE-A3, 47.5% vs 18.2%, P = 0.022) and/or vascular invasion (MAGE-A1, 41.5% vs 16.7%, P = 0.028; MAGE-A3, 49.1% vs 23.3%, P = 0.035) and, particularly, MAGE-A3, in patients with early vs advanced stage (36.5% vs 49.0%, P = 0.044), respectively. Patients expressing MAGE-A3 and NY-ESO-1 were older than those not expressing MAGE-A3 and NY-ESO-1 (MAGE-A3, 73.7 ± 7.1 vs 67.4 ± 12.3, P = 0.009; NY-ESO-1, 75.5 ± 7.2 vs 68.8 ± 11.2, P = 0.042).
The KK-LC-1 expression rate was high even in patients with stage I cancer, suggesting that KK-LC-1 is a useful biomarker for early diagnosis of gastric cancer.
Core tip: The Kitakyushu lung cancer antigen-1 (KK-LC-1) is a relatively later cancer-testis antigen and has received interest because it was reported that KK-LC-1 is a predominant antigen for cancer immunotherapy. We found that the expression rate of KK-LC-1 in gastric cancer was 79.5%, which was higher than that of other cancer-testis antigens and the same as that in both early- and late-stage patients. KK-LC-1 is a potential biomarker for early detection of gastric cancer and identification of patients at high risk for gastric cancer. Furthermore, KK-LC-1 is a potential target for immunotherapy in gastric cancer.