We then directed our attention to the CTSE, as it expresses in both Kato-III and NUGC-4 derived from sig-type GC, and also because it never expresses in MKN-7 and H-111-TC known to be originated from well differentiated tubular adenocarcinoma of stomach (tub1-type GC, Supporting Document S1). Here, CTSE is linked to tubular adenocarcinoma.