Journal: JNCI Journal of the National Cancer Institute
Article Title: Effects of In Utero Exposure to Ethinyl Estradiol on Tamoxifen Resistance and Breast Cancer Recurrence in a Preclinical Model
doi: 10.1093/jnci/djw188
Figure Lengend Snippet: Response of mammary tumors to tamoxifen. A) 9,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor growth in rats that were exposed to 0.1 ppm EE2 or vehicle control in utero. Rats either received no treatment during tumor monitoring, or when a tumor reached a size of 13 mm in diameter they received 15 mg/kg/day TAM in diet, or 1.2 g/kg/day valproic acid and 5 mg/kg/day hydralazine in drinking water.P values indicate statistically significant differences between the C and EE2 groups; one-sided Chi2-test. NS = not statistically significant. The number of tumors studied in each group varied from 24 to 59. B) Effect of adding VA+H as a second line of treatment on the development of new de novo and acquired TAM-resistant tumors in the control and in utero EE2-exposed rats is shown. P values indicate statistically significant differences between the C and EE2 groups; one-sided Chi2-test. The number of tumors was 17 in the control group and 20 in the EE2 group. C) Panel shows the expression of ERα protein, assessed by western blot, in the DMBA-induced mammary adenocarcinomas of control and in utero EE2-exposed rats that either did not receive any treatment during tumor monitoring or received TAM or TAM and VA+H. The number of tumors studied in each group was three to four. Means (SDs) are shown. C = control; EE2 = ethinyl estradiol; ER = estrogen receptor; H = hydralazine; NS = not statistically significant; TAM = tamoxifen; VA = valproic acid.
Article Snippet: Mammary tumors were induced in the female offspring on postnatal day 50 by oral gavage of 10 mg of DMBA (Sigma).
Techniques: In Utero, Expressing, Western Blot
![Response of mammary tumors to tamoxifen. A) <t>9,12-dimethylbenz[a]anthracene</t> <t>(DMBA)-induced</t> mammary tumor growth in rats that were exposed to 0.1 ppm EE2 or vehicle control in utero. Rats either received no treatment during tumor monitoring, or when a tumor reached a size of 13 mm in diameter they received 15 mg/kg/day TAM in diet, or 1.2 g/kg/day valproic acid and 5 mg/kg/day hydralazine in drinking water.P values indicate statistically significant differences between the C and EE2 groups; one-sided Chi2-test. NS = not statistically significant. The number of tumors studied in each group varied from 24 to 59. B) Effect of adding VA+H as a second line of treatment on the development of new de novo and acquired TAM-resistant tumors in the control and in utero EE2-exposed rats is shown. P values indicate statistically significant differences between the C and EE2 groups; one-sided Chi2-test. The number of tumors was 17 in the control group and 20 in the EE2 group. C) Panel shows the expression of ERα protein, assessed by western blot, in the DMBA-induced mammary adenocarcinomas of control and in utero EE2-exposed rats that either did not receive any treatment during tumor monitoring or received TAM or TAM and VA+H. The number of tumors studied in each group was three to four. Means (SDs) are shown. C = control; EE2 = ethinyl estradiol; ER = estrogen receptor; H = hydralazine; NS = not statistically significant; TAM = tamoxifen; VA = valproic acid.](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_5695/pmc06255695/pmc06255695__djw188f1.jpg)