Role and prognostic value of placenta growth factor (PlGF) in colorectal carcinomas.

Abstract

10606 Background: Placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family. PlGF is implicated in several pathologic processes, including the growth, spread of cancer and tumor angiogenesis. The aim of this study was to evaluate expression and clinical implications of PlGF in colorectal cancer. Methods: In order to ascertain the clinical significance of PlGF expression in colorectal cancer, we analysed the expression pattern of PlGF using both immunohistochemical method and real time quantitative PCR and attempted to establish if a relationship existed between PlGF and microvessel density (MVD), and subsequently between PlGF and the predicted prognosis. We investigated 72 tumor/non-tumor pairs of fresh colorectal tissues for real time PCR and a total of 83 patients with colorectal cancer were included for immunohistochemical staining. Clinico-pathological characteristics were defined according to the TNM criteria of the UICC. Clinico-pathologic factors, such as age, sex, histological types of tumors, tumor cell grade, TNM stage, lymphovascular invasion, lymph node metastasis, were reviewed. Results: The mRNA expression levels for PlGF was significantly higher in tumor than in non- tumor tissues (p = 0.001). The ratio of PlGF expression in tumor to non-tumor in the advanced staged group was significantly higher than for the early staged group. PlGF mRNA was significantly higher in III-IV stage patients than in stage I-II patients (p = 0.011). The relationship between PlGF mRNA expression and sex, histological type, lymph node status was otherwise not statistically significant. Immunohistochemically, PlGF protein expression level was significantly correlated with MVD, patient survival, and clinicopathological factors such as lymph node metastasis, TNM staging, lymphatic invasion and vascular invasion in this study. Conclusions: PlGF may be an important angiogenic factor in human colorectal cancer, and PlGF expression level was significantly correlated with positive lymph node metastases, tumor stages, and patient survival. These findings suggest that PlGF expression correlates with disease progression and may be used as a tumor marker for colorectal cancer. No significant financial relationships to disclose.