PECAM1 and neoplasm: In LNCaP tumor tissues, CD31 and CD34 were declined by 50% and 49.09% respectively in combination treatment group compared with vehicle control (P<0.01), and at the same time, quercetin or 2-ME alone also brought about downregulation of CD31 and CD34 (Quercetin: 27.45% for CD31, 30% for CD34.