Expression and significance of Musashi-1 in gastric cancer and precancerous lesions

AIM: To investigate expression of stem cell marker Musashi-1 (Msi-1) in relationship to tumorigenesis and progression of intestinal-type gastric cancer (GC). METHODS: Endoscopic biopsy specimens and surgical specimens were obtained, including 54 cases of intestinal-type GC, 41 high-grade intraepithelial neoplasia, 57 low-grade intraepithelial neoplasia, 31 intestinal metaplasia, and 36 normal gastric mucosa. Specimens were fixed in 10% paraformaldehyde, conventionally dehydrated, embedded in paraffin, and sliced in 4-μm-thick serial sections. Two-step immunohistochemical staining was used to detect Msi-1 and proliferating cell nuclear antigen (PCNA) expression. Correlation analysis was conducted between Msi-1 and PCNA expression. The relationship between Msi-1 expression and clinicopathological parameters of GC was analyzed statistically. RESULTS: There were significant differences in Msi-1 and PCNA expression in different pathological tissues (χ2 = 15.37, P < 0.01; χ2 = 115.36, P < 0.01). Msi-1 and PCNA-positive cells were restricted to the isthmus of normal gastric glands. Expression levels of Msi-1 and PCNA in intestinal metaplasia were significantly higher than in normal mucosa (U = 392.0, P < 0.05; U = 40.50, P < 0.01), whereas there was no significant difference compared to low or high-grade intraepithelial neoplasia. Msi-1 and PCNA expression in intestinal-type GC was higher than in high-grade intraepithelial neoplasia (U = 798.0, P < 0.05; U = 688.0, P < 0.01). There was a significantly positive correlation between Msi-1 and PCNA expression (rs = 0.20, P < 0.01). Msi-1 expression in GC tissues was correlated with their lymph node metastasis and tumor node metastasis stage (χ2 = 12.62, P < 0.01; χ2 = 11.24, P < 0.05), but not with depth of invasion and the presence of distant metastasis. CONCLUSION: Msi-1-positive cells may play a key role in the early events of gastric carcinogenesis and may be involved in invasion and metastasis of GC.