1. Supplementary table 1 miR-506 expression and clinocopathological factors FactorsTotal number miR-506 low expressionmiR-506 high expression P-value (n = 85)(n = 56) number% % Age (mean ± SD) 65.8 ± 12.067.5 ± 11.30.65 Gender Male885564.73358.9 0.489 Female533035.32341.1 Histological grade a, b Well & Moderately653238.13358.9 0.015 Poorly & Undifferentiated755261.92341.1 Tumor depth T1 and T2472630.62137.5 0.396 T3 and T4945969.43562.5 Lymph node metastasis Absent482630.62239.3 0.288 Present935969.43460.7 Venous invasion Absent945463.54071.4 0.328 Present473136.51628.6 Peritoneal metastasis Absent1187183.54783.9 0.95 Present231416.5916.1 Stage Ⅰ and Ⅱ 703844.73257.1 0.148 Ⅲ and Ⅳ 714755.32442.9 Staging was classified by UICC 7th edition. a Well differentiated adenocarcinoma (Well), Moderately differentiated adenocarcinoma (Moderately), Poorly differentiated adenocar- cinoma (Poorly), Undifferentiated adenocarcinoma (Undifferentiated). b Histological grade of one patient was not avaiable. SD, standard deviation.

2. Supplementary table 2 SNAI2 expression in immunohistochemical analysis SNAI2 P - value HighLow miR-506 High470.006 Low235

3. Supplementary table 3 Patient backgrounds in this study compared between early and late 10 years. FactorsTotal number 1989 - 19992000 - 2009 P-value (n = 98)(n = 43) number% % Age (mean ± SD) 65.6 ± 12.168.4 ± 10.80.426 Gender Male886061.22865.1 0.709 Female533838.81534.9 Histological grade a, b Well & Moderately654647.41944.2 0.854 Poorly & Undifferentiated755152.62455.8 Tumor depth T1 and T2473131.61637.2 0.563 T3 and T4946768.42762.8 Lymph node metastasis Absent483434.71432.6 1.000 Present936465.32967.4 Venous invasion Absent946970.42558.1 0.177 Present472929.61841.9 Peritoneal metastasis Absent1187980.63990.7 0.215 Present231919.449.3 Stage Ⅰ and Ⅱ 704748.02353.5 0.586 Ⅲ and Ⅳ 715152.02046.5 Neoadjuvant chemotherapy c Yes200.024.8 0.098 No13191100.04095.2 Adjuvant chemotherapy d Yes674650.52151.2 1.000 No654549.52048.8 Staging was classified by UICC 7th edition. a Well differentiated adenocarcinoma (Well), Moderately differentiated adenocarcinoma (Moderately), Poorly differentiated adenocarcinoma (Poorly), Undifferentiated adenocarcinoma (Undifferentiated). b Histological grade of one patient was not avaiable. c Neoadjuvant chemotherapy of eight patients were not avaiable. d Adjuvant chemotherapy of nine patients were not avaiable. SD, standard deviation.

4. Supplementary figure 1 Sequences of miR-506 binding sites in the 3′UTRs of transcripts encoding SNAI2.

5. Relative expression of SNAI2/GAPDH Relative expression of miR-506 MKN-7MKN-1 NUGC-3 P = 0.01 P = 0.02 P < 0.01 Supplementary figure 2 Endogenous miR-506 expression was measured in 3 gastric cancer cell lines. GC cell lines with high endogenous miR-506 expression (MKN-1 and NUGC-3) showed significantly lower SNAI2 expression compared to cells with low endogenous miR-506 expression (MKN-7). MKN-7MKN-1 NUGC-3

6. Relative expression of miR-506 pre-miR-506 MKN-7 P < 0.05 MKN-45 pre-miR-506 Relative expression of miR-506 30 nM 50 nM 30 nM 50 nM Supplementary figure 3. miR-506/RNU6B expression as measured by quantitative real-time PCR analysis in MKN7 cells (left) and MKN45 cells (right) after transfection with pre-miR-506. Error bars represent the SD from three replicates. Abbreviations: NC, pre-miR negative control; 30 nM, pre-miR-506 30 nM; 50 nM, pre-miR-506 50 nM. P < 0.05

7. Supplementary figure 4 The expression levels of SNAI2 were evaluated by scoring four classes (0, 1+, 2+, and 3+). Scale bar: 50 μm. 1 32 0 SNAI2