Transgenic animals of the line 8 contain the WAP-SV-T transgene. Females of this line synthesise the SV40 T-antigen in mammary gland epithelial cells during pregnancy and the lactation period, All females are 'milk-less' and the offspring have to be nursed by foster mothers, The reason for this phenomenon is a premature apoptosis during late pregnancy, Nonetheless a significant number of mammary epithelial cells escape apoptosis and all transgenic females develop breast cancer after the first lactation period.
The SV40 T-antigen induces premature apoptotic mammary gland involution during late pregnancy in transgenic mice / Y. J., Tzeng; K., Gottlob; Santarelli, Roberta; A., Graessmann. - In: FEBS LETTERS. - ISSN 0014-5793. - 380:3(1996), pp. 215-218. [10.1016/0014-5793(96)00021-x]