过去 20 年来，越来越多的证据表明，免疫球蛋白 (Igs) 可以广泛地由非 B 细胞产生，包括正常和恶性乳腺上皮细胞。在正常乳腺组织中，妊娠期和哺乳期乳腺上皮细胞表达IgG和IgA，它们可以分泌到乳汁中，可能参与新生儿免疫。另一方面，非B-IgG在乳腺癌细胞中高表达，与乳腺癌患者的不良预后相关。重要的是，在乳腺癌干细胞中发现了一组特定的 IgG，其 Asn162 位点上具有独特的 N 连接聚糖，并且在新型聚糖末端具有异常的唾液酸化修饰（称为唾液酸化 IgG (SIA-IgG)）。 /祖细胞样细胞。 SIA-IgG可显着促进迁移、侵袭和转移能力，并增强体外和体内的自我更新和致瘤性。这些发现表明乳腺上皮细胞在生理和病理条件下可以产生具有不同生物活性的Igs。在哺乳期间，这些 Igs 可能是乳汁 Igs 的主要来源，保护新生儿免受病原体感染，而在病理条件下，它们表现出致癌活性，促进乳腺癌的发生和进展。© 2024。Springer Nature Singapore Pte Ltd.

Over the past 20 years, increasing evidence has demonstrated that immunoglobulins (Igs) can be widely generated from non B cells, including normal and malignant mammary epithelial cells. In normal breast tissue, the expression of IgG and IgA has been identified in epithelial cells of mammary glands during pregnancy and lactation, which can be secreted into milk, and might participate in neonatal immunity. On the other hand, non B-IgG is highly expressed in breast cancer cells, correlating with the poor prognosis of patients with breast cancer. Importantly, a specific group of IgG, bearing a unique N-linked glycan on the Asn162 site and aberrant sialylation modification at the end of the novel glycan (referred to as sialylated IgG (SIA-IgG)), has been found in breast cancer stem/progenitor-like cells. SIA-IgG can significantly promote the capacity of migration, invasiveness, and metastasis, as well as enhance self-renewal and tumorigenicity in vitro and in vivo. These findings suggest that breast epithelial cells can produce Igs with different biological activities under physiological and pathological conditions. During lactation, these Igs could be the main source of milk Igs to protect newborns from pathogenic infections, while under pathological conditions, they display oncogenic activity and promote the occurrence and progression of breast cancer.© 2024. Springer Nature Singapore Pte Ltd.