Human/mouse microcell hybrid based elimination test reduces the putative tumor suppressor region at 3p21.3 to 1.6 cM

We have previously identified an approximately 7 cM long common eliminated region (CER), involving the 3p21.3 markers AP20R, D3S966, D3S3559, D3S1029, WI-7947, D3S2354, AFMb362wb9, and D3S32, in human chromosome 3/A9 mouse fibrosarcoma microcell hybrid (MCH) derived SCID mouse tumors. We now report the results of our more detailed analysis on 24 SCID mouse tumors derived from two MCH lines that originally carried intact human chromosomes 3. They were analyzed by fluorescence in situ hybridization (FISH) painting and PCR, using 24 markers covering the region between D3S1611 and D3S13235 at 3p22-p21.2. D3S32 and D3S2354 were regularly eliminated during in vivo tumor growth, whereas the other 22 markers, D3S1611, ACAA, D3S1260, WI-692, AP20R, D3S3521, D3S966, D3S1029, D3S643, WI-2420, MSTI. GNAI2, D3S1235, D3S1298, GLBI, WI-4193, D3S3658, D3S3559, D3S3678, WI-6400, WI-7947, and WI-10865, were regularly retained. We have defined a common eliminated region of approximately 1.6 cM (designated as CER1) inside the 7 cM CER described earlier. CER1 is flanked distally by D3S1029 and proximally by D3S643.