What does this research mean for the field?

Pregnancy associated breast cancer influenced by assisted technical reproduction shows a higher positivity rate for estrogen receptors and a different distribution of Ki67 compared to those without assisted technical reproduction. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

The aim is to assess differences in prognostic factors for pregnancy associated breast cancer related to assisted reproductive technology.

February 22, 2026

Abstract PS5-10-09: Prognostic factor pregnancy associated breast cancer by assisted technical reproduction

Key Points

The aim is to assess differences in prognostic factors for pregnancy associated breast cancer related to assisted reproductive technology.
Analyzed 164 cases of pregnancy associated breast cancer: 124 without assisted reproductive technology and 40 with it.
Examined factors including estrogen receptor, progesterone receptor, HER2, histological grade, and ki67 levels.
Compared outcomes and receptor status between the two groups.
In women without assisted reproduction, 73% were estrogen receptor positive compared to 94% in those with assisted reproduction (p<0.05).
Ki67 levels showed significant differences: 46.72% had ki67 <20 without assisted reproduction, whereas 67.85% had ki67 <20 with it (p<0.05).
No significant differences were found in progesterone receptor and HER2 status between both groups.

Abstract

Abstract Aims Study and assess the differences in the prognostic factors in pregnancy associated breast cancer by assisted technical reproduction and without . Methods Study 164 pregnancy associated breast cancer, 124 without assisted technical reproduction and 40 with assisted technical reproduction, treated in the same hospital. Analyze prognostic factors: estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 , histological grade and ki67, of pregnancy associated breast cancer with and without assisted technical reproduction. Results Patients with pregnancy associated breast cancer without assisted technical reproductio: estrogen receptor is positive in 91 (73’38 %), negative in 33 (26’61 %) patients with assisted technical reproduction ,estrogen receptor is positive in 34 (94’44 %), negative in 2 (5’55%) patients. (p0’05), ki67 20 in 50 (46’72%) patients and 20 in 57 (53’27%) patients without assisted technical reproduction, and ki67 20 in 19 (67’85 %) patients, and Ki 67 20 in 9 (32’14%) patients with assisted technical reproduction (p0’05). Progesterone receptor and HER2 receptor there was no difference between with and without assisted tecnical reproduction. (p=ns). Conclusion. Pregnancy associated breast cancer by assisted technical reproduction influence estrogen receptor and Ki67, and do not influence progesterone receptor and HER2 receptor Citation Format: M. Izquierdo, S. Baulies, M. Gallardo, C. Ara, F. Fargas, F. Tresserra, R. Fabregas, P. Barri S. Prognostic factor pregnancy associated breast cancer by assisted technical reproduction abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-10-09

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Abstract PS5-10-09: Prognostic factor pregnancy associated breast cancer by assisted technical reproduction

Key Points

Abstract

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