NONRANDOM JUMPING TRANSLOCATIONS AS A RESULT OF SV40 LARGE T-ANTIGEN EXPRESSION IN BENIGN HUMAN TUMOR-CELLS

In an attempt to analyse the cytogenetic effects caused by SV40 large T-antigen expression in cells of human benign tumors we transfected ce lls of an uterine leiomyoma characterized by a primary reciprocal tran slocation t(12;14)(q15;q24) and a pleomorphic adenoma of the salivary gland with an inversion inv(12) (q15q24.1) using a construct coding fo r SV40 large and small T-antigen. The most interesting finding was not a generally destabilized karyotype, but the strictly non-random invol vement of two chromosomal breakpoints, i.e. 5p13 and 10q11 in jumping translocations, never described before as a result of SV40 transformat ion. In addition we were able to show by non-radioactive in situ hybri dization that there was no direct relationship between the integration site of the construct and the pre-disposition of 5p13 and 10q11 to so matic recombination. The jumping translocations with consistent breakp oints observed closely resemble the cytogenetic situation seen in a va riety of human tumors with specific translocations. Based on the findi ngs described here it is tempting to assume that the expression of SV4 0 large T-antigen can induce specific karyotypic alterations following an unknown trans-acting mechanism.