Identification of vascular system in experimental carcinoma for cryosurgery--histochemical observations of lectin UEA-1 and alkaline phosphatase activity in vascular endothelium.

Histopathologic and histochemical changes in experimental carcinomas following cryotreatment were observed to detect alkaline phosphatase (ALP) activity and UEA-1 lectin binding. Experimental carcinomas were induced in the hamster cheek pouch by topical application of 0.5% DMBA acetone solution twice a week. The cryoprobe at -60 degrees C was directly attached to the tumor surface for 90 sec. Histochemically, the tumor tissue following cryotreatment was completely destroyed in the surface area by the direct freezing and such cryonecrotic tumor tissue lacks stainability. Soon after cryotreatment and before cryonecrosis takes place, it has been observed that there is an intense dilatation of capillary vessels. Histochemically, high ALP activity was limited to capillary endothelium and to inflammatory cells. Lectin UEA-1 staining was usually found in both normal and neoplastic epithelial cells which were confined to capillary vessels. At 1 to 3 hr after cryotreatment, lectin UEA-1 binding was also positive in dilated endothelial cells of the frozen tissue as well as viable remaining neoplastic epithelia by freezing. ALP activity and UEA-1 binding disappeared in capillaries of cryonecrotic area in tumor tissues. Those findings suggest that biologic membrane changes in capillary endothelium of tumor stroma occur following cryotreatment.