In summary, the KLK6 expression level was higher in gastric cancer tissue and cell lines such as AGS, SNU-216, NCI-N87, SNU-620, SNU-638, SNU-668, NUGC-3, and MKN-74 than in normal cells, and AF-resistant gastric cancer cells (NCI-N87 and SNU-620) exhibited the highest levels of KLK6. Here, KLK6 is linked to gastric cancer.