Abstract:

Objective     To study expression of lysyl oxidase(LOX) in human breast cancer and explore its relationship with clinical prognostic features（patient′s age, tumor size, lymph node metastasis, clinical stage, ER, PR and HER-2 state） and breast cancer invasion / metastasis. Methods    mRNA expressions of LOX and HIF-1α in tissues were detected in 56 cases of human breast cancer, 56 cases of normal breast and 20 cases of breast benign lesion by reverse transcriptase polymerase chain reaction (RTPCR), and protein expressions of LOX and HIF-1α by S-P immunohistochemistry. Results     Expression rates of LOX mRNA in breast cancer，normal breast tissues and breast benign lesion tissues were 57.14%, 32.14% and 25.00%, respectively, and statistical differences were significant among them (P＜0.01). Expression rates of the LOX protein in breast cancer, normal breast tissues and breast benign lesion tissues were 48.21%, 26.78% and 20.00%, respectively, and statistical differences were significant among them (P＜0.05). Expressions of LOX mRNA and protein were associated with the clinical stage and lymph node metastasis (P＜0.05), and were significantly higher in stage Ⅲ and Ⅳ breast cancer than those in stageⅠ and Ⅱ(P＜0.01), while they had no correlation with age and tumor size(P>0.05). The LOX protein had significant positive correlation with HIF-1α protein expression in breast cancer（r=0.368）. Conclusion     LOX protein and mRNA expressions are higher in breastcancer compared with normal breast tissues and breast benign lesion tissues, and LOX is probably relevant  to occurrence of breast cancer. Higher expression of LOX can increase the malignant degree of human breast cancer cells and facilitates metastasis. LOX and HIF-1α have a synergistic effect in breast cancer invasion and metastasis.

Key words: Breast cancer; Lysyl oxidase; Immunohistochemistry