CD44 and gastric cancer: In gastric CSCs, CD44+ gastric cancer cells showed self-renewal and the ability to form differentiated progeny and gave rise to CD44− cells.31 Phu Hung Nguyen showed that CD44 and ALDH are the most specific biomarkers to detect and isolate tumorigenic and chemoresistant gastric CSCs in non-cardia gastric carcinomas independent of the histologic classification of the tumor.32 CD44 is a cell surface transmembrane glycoprotein encoded by the CD44 gene, a 20-exon DNA segment,33 of which exons 1–5 and 6–20 are spliced together to form CD44s, the standard isoform.