| First Author | Santarelli R | Year | 1996 |
| Journal | Oncogene | Volume | 12 |
| Issue | 3 | Pages | 495-505 |
| PubMed ID | 8637705 | Mgi Jnum | J:31332 |
| Mgi Id | MGI:78835 | Citation | Santarelli R, et al. (1996) SV40 T-antigen induces breast cancer formation with a high efficiency in lactating and virgin WAP-SV-T transgenic animals but with a low efficiency in ovariectomized animals. Oncogene 12(3):495-505 |
| abstractText | The whey acid protein (WAP) is a major mouse milk protein and its gene expression is induced by various lactotrophic hormones (eg, estrogen, progesterone). Transgenic animals harboring the early SV40 coding region (T/t-antigen) under the transcriptional control of the WAP promoter develop breast cancer after the first lactation period. The tumor cells synthesize the SV40 T-antigen with a high efficiency indicating that WAP-SV-T expression escapes down-regulation after the lactation period. However about 5-10% of the tumors became T-antigen negative during tumor progression and WAP-SV-T expression was only demonstrable by PCR analysis. Both T-antigen positive and negative tumor cells expressed the estrogen and progesterone receptor at a comparable rate, indicating that hormone receptor levels do not determine expression of the WAP-SV-T transgene. Furthermore, WAP and WAP-SV-T gene expression are not restricted to the pregnancy-lactation period. Virgin animals also express both genes with a low efficiency and about 70% of these animals also developed T-antigen positive breast tumors. The tumor rate however was strongly reduced in ovariectomized animals, indicating that the ovary hormones play a critical role in breast cancer formation. |
