Development of thrombi in pancreatic tumors and colon adenocarcinomas. Rapamycin treatment results in the development of thrombi in orthotopic 3.6pl pancreatic tumors (A-C) and heterotopically implanted CT-26 colon adenocarcinomas (D-E). Representative high-magnification views of an area of pancreatic tumor from control and rapamycin-treated mice are shown. (A) No thrombi were found in control mice. (B) This photomicrograph shows several clotted vessels in a rapamycin-treated L3.6pl orthotopic tumor. (C) Areas of normal pancreatic tissue outside tumors in rapamycin-treated mice do not show evidence of vascular thrombosis. Similar patterns can be observed after short-term treatment with rapamycin in CT-26 tumor-bearing mice. (D) Unaffected vessels in control animals. (E) A central tumor necrosis is surrounded by viable tumor tissue containing thrombotic vessels. Total image magnification, 200×,20× Zeiss Achroplan objective lens, numerical aperture 0.45. Images were acquired with Image J software (rsb.info.nih.gov/ij).