Vascular endothelial growth factor (VEGF) is a well known factor that induces angiogenesis. Four isoforms, i.e. VEGF206, 189, 165, and 121, have been identified. We examined the isoform patterns of VEGF mRNA using reverse transcription polymerase chain reaction (RT-PCR) analysis in 61 colon cancers. All the colon cancers examined expressed VEGF121. The isoform patterns were classified into three groups: type 1, VEGF121; type 2, VEGF121 + VEGF165; type 3, VEGF121 + VEGF165 + VEGF189. Three of the 61 colon cancers examined showed type 1 expression, 26 showed type 2 expression and 32 showed the type 3 pattern. The patients with liver metastases showed the type 3 isoform expression pattern at a significantly higher incidence (12 of 16, 75%) than those without liver metastasis (20 of 45, 44%) (P=0.036). The type 3 isoform pattern was significantly associated with M1 stage (P=0.019). The patients with colon cancer and the type 3 isoform pattern showed significantly poor prognosis (P < 0.01, Cox-Mantel). The colon cancers with the type 3 pattern showed a significantly higher involvement of veins (P=0.006). These observations suggest that the aberrant type 3 expression pattern of VEGF189 mRNA isoforms is correlated with liver metastasis, M stage, and poor prognosis in colon cancer. Images Figure 2 Figure 3

BACKGROUND Cell‐retained isoforms of vascular endothelial growth factor A (VEGF‐A) have been reported to play an essential role in tumor progression through stromal neovascularization in malignant solid tumors. While more than 95% of nonsmall cell lung carcinoma (NSCLC) expresses cell‐retained VEGF‐A isoform, the clinicopathologic implications of neuropilin (NRP), considered the specific receptor for limited types of VEGF‐A isoform, are not well understood. METHODS The authors examined NRP1 and NRP2 mRNA expression in 68 NSCLCs and 15 extraneoplastic tissues by a densitometry–assisted, semi‐quantitative reverse transcription‐polymerase chain reaction. The authors determined the distinct expression of NRPs using the expression level of NRPs relative by optical density to β2‐microglobulin. The authors also investigated VEGF‐A isoforms, their receptors, and the clinical implications. Vascularity of NSCLC was morphologically estimated on sections immunostained with anti‐CD34 antibody. RESULTS Eleven of 15 extraneoplastic specimens showed NRP1 expression (73.3%) and 8 showed NRP2 expression (53.3%). The expression level of NRP1 or NRP2 of neoplasmic tissue was higher than that of extraneoplastic tissues (P < 0.01, Mann‐Whitney U test). Fifty‐five and 44 NSCLCs expressed NRP1 and NRP2, respectively. Forty patients co‐expressing NRP1 and NRP2 showed significantly poorer prognosis and increased vessel counts as compared to those 28 cases without co‐expression (P < 0.05, log‐rank test; P < 0.05, Mann‐Whitney U test). CONCLUSIONS The co‐expression of NRP1 and NRP2 genes is significantly correlated with tumor progression through neovascularization in NSCLC. These results suggest that both NRP1 and NRP2 are key molecules for stromal vascularization by cell‐retained VEGF in NSCLC. Cancer 2002;95:2196–201. © 2002 American Cancer Society. DOI 10.1002/cncr.10936

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