OBJECTIVETo investigate the expression of tumor stem cell surface marker CD44 in gastric cancer and its clinical value.

METHODSExpressions of CD44 protein family, including CD44s, CD44v5 and CD44v6, in gastric cancer and peritumoral tissues specimens were detected by immunohistochemistry in 156 patients with gastric cancer from December 2006 to December 2007. Associations of CD44 family expressions with of clinicopathological parameters and prognosis in gastric cancer patients were examined.

RESULTSThe positive rates of CD44s expression in gastric cancer and peritumoral tissues were 50.0%(78/156) and 40.3%(63/156) respectively(P>0.05). The positive rates of CD44v5 and CD44v6 expression in gastric cancer were 49.3% and 63.4%, significantly higher than those in peritumoral tissues(7.6% and 0 respectively, all P<0.05). There were no positive correlations among the expression levels of CD44s, CD44v5 and CD44v6(all P>0.05). High expression rate of CD44s was associated with depth of invasion, lymph node metastasis and TNM stages. CD44v5 expression was only associated with depth of invasion. CD44v6 expression was associated with depth of invasion, lymph node metastasis, TNM stages and Lauren classification. The 5-year survival rates in the positive and negative groups of CD44s, CD44v5 and CD44v6 expressions were 35.8% and 52.5%(P<0.05), 38.9% and 49.3%(P>0.05), 26.2% and 75.4%(P<0.05) respectively. Only the CD44v6 expression was an independent prognostic factor for gastric cancer(RR=1.931, 95%CI:1.183-3.152).

CONCLUSIONCD44 plays an important role in invasion and lymph node metastasis, and may serve as potential predictors of prognosis in gastric cancer.