Background & objective: Our previous study found that BALB/c mice are highly susceptible to transplanted SP2/0 tumors, whereas C57BL/6J mice are barely susceptible. This study was to detect genetic modifier loci that would influence the size of transplanted SP2/0 tumors using these two inbred mouse strains and their F2 progenies.
Methods: A total of 5x106 SP2/0 cells were inoculated subcutaneously in the left hide legs of 208 F2 mice derived from BALB/c and C57BL/6J strains. At the 17th day since inoculation, all mice were killed, the number and weight of transplanted tumors were recorded. A whole genomic scan using 85 microsatellite markers covering all chromosomes of the mouse, and composite interval mapping analysis were conducted in 208 F2 mice.
Results: Eight loci, with the percent of the total variance explanation of > or = 10% and P value of < or = 0.01, were found responsible for tumor formation. They were mapped on Chr1 (D1Mit113, 55cM and D1Mit407, 52 cM), Chr4 (D4Mit226, 41cM), Chr9 (D9Mit302, 55cM), Chr10 (D10Mit264, 42cM), Chr11 (D11Mit115, 35cM), Chr14 (D14Mit125, 45cM), and Chr18 (D18Mit123, 31cM).
Conclusions: Multiple genetic variants affect individual susceptibility to transplanted SP2/0 tumors in mice. Identification of the target loci may be helpful in conformation of the haplotype and understanding of the genes responsible for tumor susceptibility or resistance.