CD44 and CD44v6 are Correlated with Gastric Cancer Progression and Poor Patient Prognosis: Evidence from 42 Studies

Background/Aims: The prognostic power of the levels of total CD44 and its isoform CD44v6 for patients with gastric cancer (GC) remains controversial. Therefore, our study aims to generalize the clinicopathological and prognostic significance of these two proteins in GC. Methods: A literature search of the PubMed, Web of Science and Embase databases was conducted to identify eligible studies. The odds ratio (OR) with a 95% confidence interval (CI) was used to assess the effects. Results: In all, 42 studies including 6,229 patients were included in this analysis. Total CD44 was mentioned in 21 papers, and the results showed that CD44 was positively correlated with the T category, the N category, distant metastasis, lymphatic invasion and TNM stage. Moreover, patients with CD44 overexpression had a lower 5-year overall survival (OS) rate (OR = 3.35, 95%CI = 1.83-6.13). CD44v6 was mentioned in 24 studies, with results that were similar to those for total CD44. However, total CD44 or CD44v6 expression was not correlated with tumor size and histological grade. Conclusion: High CD44 or CD44v6 expression levels were correlated with cancer progression and poor prognosis in patients with GC. Both CD44 and CD44v6 may be useful diagnostic or prognostic biomarkers for GC.