Major Problems in Childhood Cancer

Abstract

<h3>OBJECTIVE</h3> To explore the inhibitory effects of quercetin on angiogenesis of experimental mammary carcinoma. <h3>METHODS</h3> A 7,12-dimethylbenzanthracene (DMBA)-induced animal model of mammary carcinoma was established in rats. Seventy-nine female Sprague-Dawly rats were randomized into 4 groups namely, DMBA, DMBA with tamoxifen (TAM), DMBA with quercetin and control agents identified as group A, B, C and D respectively. Treatment was for 28 weeks. Samples of breast tissues were collected for histopathological observation and microvessel density (MVD) estimation by light microscopy. The expression of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and the protein product of H-ras were examined by immunohistochemical staining. <h3>RESULTS</h3> ① The mammary carcinoma occurrence rate and mean mammary tumor diameter of group A (76.2%, 2.37cm) were significantly higher than that in group B (40.9%, 1.82cm), C (45.5%, 1.71cm) and D (0%, 0cm) (<i>P</i>&lt;0.05). There was no significant difference between groups B and C (<i>P</i> &gt; 0.05), which indicated that quercetin inhibited the incidence and growth of mammary carcinoma; ② MVD estimation and immunohistochemical staining for VEGF, bFGF and the H-ras protein product showed significant differences between groups A and B, as well as groups A and C (<i>P</i> &lt; 0.05), but no significant difference between groups B and C (<i>P</i>&gt; 0.05). <h3>CONCLUSION</h3> Quercetin can reduce the DMBA-induced mammary carcinoma incidence and tumor growth. The following mechanisms may be responsible for these results: ① Inhibition of the synthesis of the H-ras protein, causing inhibition of proliferation of the tumor cells and tumor angiogenesis. ② Inhibition of the expression of angiogenesis-related growth factors such as VEGF and bFGF, so that angiogenesis in the mammary carcinomas is suppressed, with decreased mammary MVD in the rats receiving quercetin treatment.