T-cell receptor gene rearrangement in primary tumors: effect of genetic background and inducing agent.

The status of T-cell receptor beta and gamma genes has been assessed in a series of primary tumors induced by a chemical carcinogen or by gamma-irradiation using two inbred strains of mice. It appears that these well-characterized regimens of carcinogenesis yield T-cell tumors showing gene rearrangements consistent with a clonal origin of the tumors. Individual rearranged bands seem to represent orthodox, intralocus recombination events. A variety of rearrangement phenotypes are observed, most strikingly for the gamma genes, and differences in the degree of T-cell receptor gene rearrangements observed can be categorized according to the inducing agent and to the genetic background of the mice, with the implication that premalignant thymocytes have been captured in different stages of T-cell development. Additionally, primary tumors were shown to express significant levels of mature beta gene mRNA.