Lymphangiogenetic Role On Lymphatic Metastasis Of Rectal Cancer And Its Clinical Significance

OBJECTIVE: To study the lymphangiogenesis of rectal cancer (RC).To investigate lymphangiogenetic role on lymphatic metastasis of RC andits clinical significance. METHODS: In our study, the protein expression of Podoplanin,CD34, VEGF-C, VEGFR-3 and VEGF in 63 cases of RCs and 63 normalrectal tissues was detected by immunohistochemistry. LVD and MVD wereevaluated by immunohistochemistry with anti-human Podoplanin andCD34 antibody respectively. Moreover, the relationship between lymphaticvessel density (LVD) and microvessel density (MVD), expression ofVEGF-C, VEGFR-3 and VEGF, clinicopathological features and prognosisof patients with RC was retrospectively analyzed. RESULTS: Podoplanin-positive lymphatics appeared in both RC andnormal tissues. The peritumoral LVD (LVDpt) was significantly higherthan not only the intratumoral LVD (LVDit) but also the LVD of normaltissues, but the difference between the two latters was not significant. TheLVDpt was significantly associated with the expression of VEGF-C andVEGFR-3 but not that of VEGF and MVD. On the contrary, MVD had asignificant correlation with the expression of VEGF rather than VEGF-Cand VEGFR-3. Moreover, the LVDpt was significantly associated withlymph nodes metastasis, lymphatic involvement and Duke,s staging in RCs,so was the expression of VEGF-C and VEGFR-3. According to survivalanalysis,the LVDpt, expression of VEGF-C and VEGFR-3 were allcorrelated with the five-year survival rate of patients with RC significantly. CONCLUSION: Our study suggests : In RC especially peritumoralregion, there is lymphangiogenesis activated by VEGF-C rather than VEGF,which is an important event in the progression of RC and might play anessential role in lymphatic metastasis. Furthermore, evaluating LVDpt andexpression of VEGF-C and VEGFR-3 could be valuable to predictprognosis of patients with RC.