Expression of VEGF‐C and VEGF‐D at the invasive edge correlates with lymph node metastasis and prognosis of patients with colorectal carcinoma

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Abstract
Vascular endothelial growth factor (VEGF)‐C and VEGF‐D are potent lymphangiogenic factors produced by tumor and stromal cells. The purpose of this study was to determine whether expression of VEGF‐C and/or VEGF‐D correlates with clinicopathological features of human colorectal carcinoma. Expression of mRNAs for VEGF‐C, VEGF‐D, and their receptor VEGFR‐3 was examined by reverse transcription‐polymerase chain reaction (RT‐PCR) in six colon carcinoma cell lines and in fresh endoscopic biopsy specimens from 20 patients with colorectal carcinoma. Expression of VEGF‐C and VEGF‐D protein was also examined immunohistochemically in 139 archival surgical specimens of human colorectal carcinoma. Of the six cell lines, one (Colo320D) constitutively expressed VEGF‐C and four (Colo320D, DLD‐1, km12sm, km12c) constitutively expressed VEGF‐D mRNA. Expression of VEGF‐D mRNA was increased under low oxygen conditions, and all six cell lines constitutively expressed VEGF‐D mRNA under hypoxic conditions. Of the 139 specimens of human colorectal carcinoma, 65 (46.8%) showed intense VEGF‐C immunoreactivity and 41 (29.5%) showed intense VEGF‐D immunoreactivity. In 49 (75.3%) of the 65 and 20 (48.8%) of the 41 cases, heterogeneous intratumoral staining was observed for VEGF‐C and VEGF‐D, respectively, with the highest levels of expression at the invasive edges. VEGF‐C expression correlated with the depth of tumor invasion, lymphatic involvement, venous involvement, lymph node metastasis, and liver metastasis, and VEGF‐D expression correlated with the depth of tumor invasion, lymph node metastasis, and liver metastasis. No correlation was observed between VEGF‐C and VEGF‐D expression in tumors. The survival time of patients with VEGF‐C‐positive tumors was significantly shorter than that of patients with VEGF‐C‐negative tumors, and the survival time of patients with VEGF‐D‐positive tumors was significantly shorter than that of patients with VEGF‐D‐negative tumors. The survival time of patients with both VEGF‐C‐ and VEGF‐D‐positive tumors was significantly shorter than that of patients with both VEGF‐C‐and VEGF‐D‐negative tumors. These results suggest that VEGF‐C and VEGF‐D may be independent and important prognostic factors in patients with human colorectal carcinoma. (Cancer Sci 2004; 95: 32–39)