DIFFERENTIAL ELIMINATION OF 3P AND RETENTION OF 3Q SEGMENTS IN HUMAN MOUSE MICROCELL HYBRIDS DURING TUMOR-GROWTH/

We have previously found that human chromosome 3 was fragmented in the course of in vivo tumor growth of monochromosomal human/mouse (A9 fib rosarcoma parent) microcell hybrids in SCID mice. Marker analysis of t umor cell lines has identified a regularly eliminated 7 cM segment on 3p21.3 referred to as the common eliminated region (CER). The same reg ion is frequently affected by LOH in a variety of human carcinomas. Th e present study is a comparative chromosome painting, reverse painting , and PCR marker analysis of microcell hybrids (MCHs) that originally contained an intact chromosome 3 from two alternative donors, during a nd after four passages in SCID mice. We found regular elimination of 3 p in parallel with preferential retention of 3q. In addition to CER on 3p, we can now define a common retained region (CRR) on 3q. It includ es eight markers between D3S1282 (3q25-q26) and D3S1265 (3q27-qter) an d spans approximately 43 cM. These observations are concordant with th e frequent loss of corresponding 3p regions and the frequent retention , with occasional amplification, of 3q in several types of human tumor s. (C) 1997 Wiley-Liss, Inc.