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,57low-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-1and PCNA expression in different pathological tissues(χ2=15.37,P<0.01;χ2=115.36,P<0.01).Msi-1and PCNA-positive cells were restricted to the isthmus of normal gastric glands.Expression levels of Msi-1and 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 intestinaltype 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-1expression 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. 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- 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 There was significant difference between Msi-1and PCNA expression in different pathological tissues (χ2 = 15.37, P <0.01; χ2 = 115.36, P <0.01) ere 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) difference compared to low or high-grade intraepithelial neoplasia. Msi-1 and PCNA expression in intestinal type GC was higher than high-grade intraepithelial neoplasia (U = 798.0, P <0.05; U = 688.0, P <0.01) Significant positive correlation between Msi-1 and PCNA expression (rs = 0.20, P <0.01) .Msi-1expression in GC tissues was correlated with their lymph node metastasis and tumor node metastasis stage (χ2 = 12.62, , 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.