RSAD2 and neoplasm: In addition, immunofluorescence and immunoblot analyses showed that a CSC marker, CD44, was strongly expressed in tumor tissues of MKN28 controls but not in MKN28 viperin-KD cells (Figure 6, D and E), and viperin expression was detected in both CD44+ CSCs and CD44– non-CSCs in tumor tissues of MKN28 controls (Figure 6D).