Abstract: Abstract: Objective To evaluate the expression and relationship of miR-100 and FZD-8, one of the major compo⁃ nents of Wnt signaling pathway, and the correlation of their expressions with lymph node metastasis in patients with breast cancer. Methods The expression of miR-100 was determined in 50 samples of human breast cancer tissues and adjacent normal tissues by in situ hybridization. The correlation of miR-100 expression with lymph node metastasis was analyzed by Mann-Whitney U test. The expression of FZD-8 was measured in 50 samples of human breast cancer tissues and adjacent normal tissues by immunohistochemistry. The correlation of the miR-100 expression with the protein expression of FZD-8 was evaluated by Pearson rank analysis. Results The expression of miR-100 was significantly lower in human breast can⁃ cer tissues than that in adjacent normal breast tissues [2.00 (1.00, 3.00) vs. 6.00 (3.50, 8.00)]. The miR-100 expression was lower in patients with lymph node metastasis than that in patients without lymph node metastasis [1.50 (1.00, 2.75) vs. 3.00 (2.00, 4.00)]. The expression of FZD-8 was significantly higher in human breast cancer tissues than that in adjacent normal breast tissues [8.00 (6.00, 9.00) vs. 6.00 (3.75, 9.00)]. The miR-100 expression was negatively correlated with the FZD-8 pro⁃ tein expression in human breast cancer tissues (rs=-0.592, P < 0.001). Conclusion The miR-100, as an anti-metastasis- miRNA, may involve in the metastasis of breast cancer, which may be related with the regulation of the expression of FZD-8.

Key words: breast neoplasms, lymphatic metastasis, Wnt proteins, microRNAs, miR-100, Wnt pathway, FZD-8