OBJECTIVEMouse tumors were subcutaneously transplanted into different mouse strains and their growth and metastatic properties were checked, to explore the possibility of establishing animal tumor models in different mouse strains other than their normal host strains.

METHODSSeven mouse tumor cell lines: H22, S180, U14, FC, Ca761, SMG-A and DCS were transplanted into C57BL/6J, ICR or KM mice, and their tumorigenicity, growth and metastasis were recorded and analyzed.

RESULTSThe tumor formation rate of H22 cells in both the C57BL/6J and ICR mice was 100%, but the growth of H22 tumors was significantly faster in the C57BL/6J (2.8 ± 0.4)g than in the ICR mice (1.5 ± 0.5)g at the 17th day after transplantation (P<0.001). The S180 tumors grew stably in C57BL/6J mice and the tumor formation rate was 100%. The U14 inoculated into C57BL/6J and KM mice showed both lymphatic and lung metastasis and formed significantly larger tumors in KM mice [(12.6 ± 3.4)g] than that in the C57BL/6J mice [(10.2 ± 2.2)g] on the 32rd day after transplantation (P = 0.002). Transplantation of FC, Ca761, and SMG-A did not form tumors or the tumors were completely regressed later in C57BL/6J mice. DCS cells formed tumors in C57BL/6J mice, but some of the tumors regressed. The retained tumors were passaged in C57BL/6J mice, and the substrain DCS-C57 cells was established which showed stable growth and had a 100% tumor formation rate and 100% lung metastasis rate in C57BL/6J mice.

CONCLUSIONSCross-strain transplanted tumors can be successfully established by inoculation of poorly differentiated and highly malignant tumor cells into different mouse strains. Some highly immunogenic tumor cells may form tumor, however, the tumors are regressed later, and can not establish cross-strain transplanted tumors in other mouse strains. Stable transplanted tumor models can be obtained from the partially regressed tumors after continuous passages in vivo.