RESUMEN
INTRODUCTION: The objective of this study was to determine the reproducibility in a murine model of renal tumours of various histological strains that could be useful for investigating the response to target drugs. MATERIAL AND METHODS: Development and analysis of the "in vivo" model: tumour xenograft of renal cell carcinomas with Balb/c nude athymic mice. Nontumourous human renal tissue was implanted in the interscapular region of 5 mice, chromophobe renal cell carcinoma was implanted in 5 mice (which, after checking its growth, was prepared for implantation in another 10 mice) and Fuhrman grade 2 clear cell renal cell carcinoma (CCRCC) was implanted in 5 mice (which was also subsequently implanted in 10 mice). We monitored the tumour size, onset of metastases and increase in size and number of tumours. When the size had reached a point greater than or equal to locally advanced or metastatic carcinoma, the animals were euthanised for a pathological and immunohistochemical study and a second phase of implantation. RESULTS: The subcutaneous xenograft of the healthy tissue did not grow. The animals were euthanised at 6 months and no renal tissue was found. The chromophobe renal cell carcinoma cells grew in the initial phase (100%); however, in the second phase, we observed a chronic lymphomonocyte inflammatory reaction and a foreign body reaction. The CCRCC grew at 5-8 months both in the first and second phase (100%), maintaining the tumour type and grade. CONCLUSIONS: The model with athymic Balb/c nude mice is useful for reproducing CCRCC, with the same histological characteristics and aggressiveness as native human tumours, promoting the development of the second experimental phase.