Several studies have showed a highly significant association between VEGF expression and tumor grade in CRC (Vahedi et al., 2015; Wen et al., 2015; Hedaya et al., 2015; van Triest et al., 2000), but no significant difference was observed by Hashim et al (2010). As regard the lymph node metastasis and the tumor stage, we found a highly significant relation with VEGF expression, that matched with various works (Mohamed et al., 2016; Vahedi et al., 2015; Xu et al., 2005; Minagawa et al., 2002; White et al., 2002) who found an association between the tumor stage and lymph node metastasis with VEGF expression . Our findings support that high VEGF expression is linked to advanced CRC. However, Hashim et al (2010) found no significant difference between the stages of CRC and VEGF expression, may be due to their use of different scoring system that depends only on the assessment of the extent of positive cells.
Our results observed no statistically significant relation between VEGF expression and some clinicopathological features, such as patient age, sex and tumor site (p >0.05). These were confirmed by some researches (Mohamed et al., 2016; Vahedi et al., 2015; Zhan et al., 2008; Alli et al., 2005), but in contrary with the results of van Triest et al (2000) who identified a significant relation between VEGF expression and patient age and sex.
In order to evaluate the contribution of FAS expression to tumor angiogenesis, we have evaluated the association between the immunohistochemical FAS and VEGF expression. Our result revealed a highly significant association between them (P < 0.001). These data suggest that high level of FAS enzyme is involved in the development of angiogenesis in CRC cases may be through VEGF upregulation. Our results are in agreement with Zaytseva et al (2014) who showed that a stable FAS knockdown in CRC cells leads to suppression of proliferation, migration and tubulogenesis of the endothelial cells and reduction of vascular endothelial growth factor receptor-2 signaling in vitro.