The Construction Of Subcutaneous Mouse Model Inolving Transplantation Of Patient Pancreatic Cancer Tissue And The Observation Of Biological Behavior

1. Objective:To build the subcutaneous mouse model by transplant the patient pancreatic cancer tissue fragments directly, extend the tumors in mice and perform the immunohistochemical detection for discussing the biological characteristics of the xenografts.2. Methods:2.1The fresh pieces of pancreatic cancer tissue were obtained with the help of operators at the time of surgical reaction. Then transplant the tissue fragments under the skin of the NOD/SCED mice in one hour. This is the first generation. Observe the growth of the tumor, and transplant it into the next generation when the diameter of the tumor has reached to8mm. From the second generation, we can use the nude mice to build the subcutaneous xenograft. Continue to observe the growth of the tumor.2.2Tumors from each generation were fixed in paraformaldehyde. Then Paraffin embedding, serial sections, HE staining and immunohistochemical staining for detection of Ki67andVEGF.3. Results: 3.1The construction of subcutaneous xenograft models:We have obtained tumor pieces from a total of19pancreatic cancer patients for transplanting into NOD/SCID mice. Five of the19transplanted tumors successfully engrafted. Among them, four of the samples were collected from primary pancreatic tumors, and one of the samples were collected from pancreatic cancer omentum metastases. The success rate is26.3%. It is38.5%by Calculating the specimen tissue blocks only. The first xenograft has passaged to the fourth generation and achieved success for using nude mice to transplant. The other four xenogratfs have passaged to the second generation. The average growth weeks of the first generation is5.6±1.1w. The average size of the tumors is507.83±426.05mm3. With the increase of generaions, tumor growth is accelerated.3.2HE staining:By comparing the human pancreatic tumor tissue and each generation of mice xenografts, the result shows that they have the same histopathologic morphology almost, similar to the primary pancreatic tumors.3.3Immunohistochemical staining:Both Ki67and VEGF have positive expressions. Ki67is the nucleus staining. VEGF is the cytoplasmic staining. The integral optical densities (IOD) of Ki67, which come from the human pancreatic tumor tissue, the first generation of NOD/SCID mice xenograft, the second generation of NOD/SCID mice xenograft, the third generation of NOD/SCID mice xenograft, the second of nude mice xenograft and the third generation of nude mice xenograft, are separately (1.15±0.42)×104,(1.65±0.80)×104,(2.89±0.31)×104,(3.29±0.42)×104,(3.25±1.16)×104,(3.41±1.09)×104. The IODs of VEGF are separately (0.12±0.09)×104,(0.18±0.08)×104,(0.30±0.09)×104,(0.41±0.18)×104,(0.19±0.07)×104,(0.30±0.16)×104. Both present a trend of increasing.4. Conclusion:Through transplanting the human pancreatic cancer tissue fragments directly, we have constructed the subcutaneous mouse model of pancreatic cancer successfully, which can keep the histologic features of pancreatic cancer preferably. It will play an important part in the research of human pancreatic cancer, especially for the tumor microenvironment, gene expression, chemotherapy and radiotherapy.