Prognostic Value of Cancer Stem Cell Markers CD44 and ALDH1/2 in Gastric Cancer Cases

Purpose: To determine expression levels of CD44 and ALDH1/2, known cancer stem cell (CSC) markers, in stomach adenocarcinomas and assess relationships with clinicopathologic parameters and prognosis. Methods: Eighty patients diagnosed with gastric cancer between the years 2011-2015 were included in this study of clinicopathologic characteristics, postoperative prognostic indexes and stem cell marker CD44 and ALDH1/2 expression in paraffin-embedded tumour sections analyzed immunohistochemically. Clinicopathologic parameters were evaluated using the chi-square test and t-test. Survival analyses were conducted using Kaplan-Meier statistics. Results: We observed positive CD44 and ALDH1/2 staining in 45.0 % and 67.5% of tumour tissues, respectively, but not in normal gastric mucosa. Recurrence-free survival (RFS) was found to be shorter in cases with high levels of CD44 expression (p=0.004). Similarly, short RFS was observed in patients with high levels of CD44 and ALDH1/2 co-expression (p=0.004). Furthermore, tumour invasion depth was found to correlate with high CD44 and ALDH1/2 co-expression (p=0.028). Conclusion: The cancer stem cell markers CD44 and ALDH1/2 may indicate poor patient prognosis and play a role in tumour development and invasion.