PGF and neoplasm: PlGF and VEGF are important factors involved in tumour angiogenesis and were significantly up-regulated in liver tissue at 16W (respectively p < 0,05 and p < 0,001), 20W (p < 0,05 and p < 0,01) and tumour tissue samples at 25W DEN (p < 0,05 and p < 0,01).