Evaluation of engraftment and growth dynamics of orthotopic and heterotopic in vivo models of human breast cancer

Purpose of the study. This work was to assess the engraftment and growth dynamics of breast cancer xenografts during orthotopic and subcutaneous injection using various types of biological material, as well as to develop an adequate model of breast cancer for further research.Materials and methods. We used a disaggregated fragment of a tumor obtained from the patient, a certified breast cancer cell line VT20 – human breast carcinoma; a primary human breast carcinoma cell line. Female immunodeficient mice of the Balb/c Nude line in the amount of 36 animals were used as recipient animals. The subcutaneous and orthotopic models of breast cancer were developed in this project. Tumor growth was observed for 28 days from the moment of injection and tumor nodes were measured 2 times a week until the end of the experiment. Results were assessed using medians and percentiles. The nonparametric Mann-Whitney test was used to assess the significance of differences.Results. The dynamics of the growth of tumor cells when injected into various sites was determined in the process of this work. The most successful in terms of a subcutaneous injection was the injection of tumor cells of the certified VT20 line. By the end of the experiment, the median tumor node of this group was 100.32 mm³. The analysis revealed tumor dynamics with orthotopic injection of tumor material, and the median volume of the tumor node in the group with the passport culture cell VT20 and the primary culture cell reached the same value – 149.22 and 148.25. mm³. It was found that both the cell line and the cell suspension were injected into tumor nodes that reached a significantly larger volume when injected orthotopically.Conclusion. We have obtained a tumor model of breast cancer using various methods of material implantation and with the possibility of further use in testing new pharmacological substances.