Expression of vascular endothelial growth factor, matrix metalloproteinase-9 and E-cadherin in the process of lymph node metastasis in oesophageal cancer

Lymph node metastasis is a strong independent prognostic factor for oesophageal cancer. The expression of matrix metalloproteinases (MMPs) and reduction of E-cadherin correlate with lymph node metastasis of oesophageal cancer. We previously reported that the expression of vascular endothelial growth factor (VEGF) is associated with lymph node metastasis. This study was designed to determine whether VEGF, MMP-9 and E-cadherin expression is stable or changes in the process of lymph node metastasis of oesophageal cancer. Using immunohistochemistry, we detected VEGF, MMP-9 and E-cadherin expression in paraffin-embedded specimens of oesophageal squamous cell carcinoma. We classified 134 primary tumours and 174 nodal metastases using two different criteria: the absence [Group N(-)] or presence [Group N(+)] of nodal metastasis, and the stage of metastasis - Early Stage (cancer cells < 50% of lymph node) or Late Stage (greater than or equal to 50%)- and compared the expression among two groups and among two stages. The expression rates of Group N(-), Group N(+), Early Stage and Late Stage are as follows: VEGF (49%, 74%, 60%, 33%), MMP-9 (76%, 65%, 95%, 69%) and E-cadherin (49%, 24%, 55%, 38%). VEGF expression was down-regulated in Late Stage lymph node metastasis, while MMP-9 expression was elevated in Early Stage metastasis. E-cadherin expression is restored somewhat in Early Stage metastasis, but suppressed again in Late Stage metastasis. These data suggest that the expression of VEGF, MMP-9 and E-cadherin each change in the process of lymph node metastasis in oesophageal cancer, and that the patterns of change are different.