Analysis of Tumor Suppressor Gene Regions Involved in Radiation Mammary Carcinogenesis of p53 and Atm Heterozygous Deficient Mice

Abstract

To examine possible contributions of individual tumor suppressor genes to radiation mammary carcinogenesis, we have investigated the loss of heterozygosity (LOH) in the tumors from p53 and Atm heterozygous deficient mice. (BALB/cHeA-p53^+/KO x MSM/Ms-Atm^+/KO)F₁ hybrid female mice were exposed to single dose of 5Gy of X-rays at 5 weeks of age. Fifty-four mammary adenocarcinomas (MC) (25%) were observed in 219 irradiated female mice. The MC frequently developed between 211 and 240 days after birth. Twenty MC (37%) were observed in p53^+/KO-Atm^+/+ mice, and 34 MC (63%) developed in p53^+/KO-Atm^+/KO mice. Frequencies of LOH in MC were 30%, 52%, 20% 28%, 57% and 65% on chromosomes 5, 8, 9, 10, 11 and 12, respectively. The LOH pattern in the MC from p53^+/KO-Atm^+/+ mice was similar to that of the p53^+/KO-Atm^+/KO mice. Precise allelotype analysis on chromosome 8 is in progress. [J Radiat Res 44:399 (2003)]