Cancer stem cells biomarkers in gastric carcinogenesis.

BACKGROUND: Gastric carcinogenesis is a multistep process, involving multiple molecular alterations, including changes in cancer stem cells (CSCs). The present investigation was undertaken to determine whether changes in cancer stem cells could be utilized as a marker of progression of gastric carcinogenesis by examining the expression of gastric CSCs at different stages of carcinogenesis. METHODS: Ninety-three cases with 31 in each group of chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), or gastric cancer (GC) were analyzed immunohistochemically for proliferating cell nuclear antigen (PCNA) and Bcl-xl as biomarkers of proliferation and apoptosis, respectively, and CD44, CD166, and LGR5 levels by qRT-PCR as markers of gastric CSCs. Additionally, the levels of P53 and phosphorylated form of epidermal growth factor receptor (p-EGFR) were examined. RESULTS: While the levels of each of these biomarkers were found to be low to moderate in CSG and CAG patients, they were markedly increased in GC patients, in whom co-expression of CD44 with LGR5 and CD166 with p-EGFR was found to be the highest. We have also observed that although the expression of different CSC markers as well as the levels of p-EGFR were increased in precancerous lesions (CSG and CAG), they are further augmented in GC suggesting that they may play a pivotal role in the development and progression of gastric cancer. CONCLUSIONS: Our observations suggest that the progression to gastric carcinogenesis from preneoplastic lesions such as superficial gastritis and chronic atrophic gastritis is associated with induction of CSCs together with increase in cell proliferation and inhibition of apoptosis.

The effect of folic acid on the development of stomach and other gastrointestinal cancers.

OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. RESULTS: A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. CONCLUSIONS: This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar effect of beta-carotene was also detected. Also, folic acid may be of use to treat atrophic gastritis by preventing or reversing the precancerous lesions.