The exact histogenesis of high-grade urothelial tumors may be difficult to ascertain in metastatic sites.Clinical information may be of tremendous value in such cases. 如果此高級別尿路上皮腫瘤發生轉移，轉移灶內瘤細胞的組織發生會很難確定，此時臨床病史尤為重要。
VEGF-induced metastatic colonies were surrounded by densely packed stromal cells before detectable angiogenesis, suggesting that VEGF is involved in the initiation of desmoplasia. 在血管形成之前，引入血管內皮生長因子表達的轉移灶被高密度的間質細胞包裹，表明血管內皮生長因子參與結締組織增生的過程。
