Diagnosis and prognosis of breast cancer is based on disease staging identified through histopathological and molecular biology techniques. Animal models are used to gain mechanistic insights into the development of breast cancer. C(3)1-TAg is a genetically engineered mouse model that develops mammary cancer. However, carcinogenesis caused by this transgene was characterized in the Friend Virus B (FVB) background. As most genetic studies are done in mice with C57BL/6 J background, we aimed to define the histological alterations in C3(1)-TAg C57BL/6 J animals. Our results showed that C3(1)-TAg animals with C57BL/6 J background develop solid-basaloid adenoid cystic carcinomas with increased fibrosis, decreased area of adipocytes, and a high proliferative index, which are triple-negative for progesterone, estrogen, and human epidermal growth factor receptor 2 (HER2) receptors. Our results also revealed that tumor development is slower in the C57BL/6 J background when compared with the FVB strain, providing a better model to study the different stages in breast cancer progression.

乳腺癌的诊断和预后基于通过组织病理学和分子生物学技术确定的疾病分期。动物模型用于获得对乳腺癌发展的机制见解。C(3)1-TAg 是一种基因工程小鼠模型，可发展为乳腺癌。然而，由这种转基因引起的致癌作用在 Friend Virus B (FVB) 背景中被表征。由于大多数遗传研究是在具有 C57BL/6 J 背景的小鼠中进行的，我们旨在确定 C3(1)-TAg C57BL/6 J 动物的组织学改变。我们的研究结果表明，具有 C57BL/6 J 背景的 C3(1)-TAg 动物会发展为实体基底样腺样囊性癌，伴有纤维化增加、脂肪细胞面积减少和高增殖指数，孕酮、雌激素、和人表皮生长因子受体 2 (HER2) 受体。我们的研究结果还表明，与 FVB 菌株相比，C57BL/6 J 背景中的肿瘤发展较慢，为研究乳腺癌进展的不同阶段提供了更好的模型。