MULTIGENIC CONTROL OF SKIN TUMOR SUSCEPTIBILITY IN SENCARA PT MICE/

Skin tumors induced in mice by initiation-promotion (2 mu g DMBA-2 mu g TPA) protocols were found to be under multigenic control, Eighty-one N2 mice from the cross (BALB/cAnPt X SENCARA/Pt)F1 X SENCARA/Pt that were either solidly resistant (no papillomas) or highly susceptible (g reater than or equal to 7 papillomas/mouse) were subjected to a 'genom e scan' using 89 microsatellite markers to check for associations with susceptible and resistant phenotypes, A locus on Chr 5 (Skts4) was fo und to control the susceptibility of SENCARA/Pt mice and the resistanc e of BALB/cAnPt mice to papilloma formation. In addition, higher than expected linkage scores were seen for the markers D9Mit271, D11Mit268 and D12Mit56. Further work is required to establish whether genes dete rmining papilloma formation are located in these regions of the genome , In general, no evidence was seen for loss of heterozygosity in micro satellite markers on Chrs 5, 9 and 11 in 17 microdissected papillomas from (BALB/c X SENCARA)F1 hybrid mice.