Plac1, also known as Placenta-specific 1, is an X-linked gene. It is primarily expressed in cells derived from the trophoblast lineage during embryonic development and has fundamental roles in placental function and development [1]. Aberrant Plac1 expression is associated with the phosphoinositide 3-kinase (PI3K)/AKT pathway, and it is involved in tumor-related processes such as the motility, migration, and invasion of tumor cells [2].

In mouse models, when Plac1 is ablated, it causes aberrant placental cell layer organization, suggesting its importance in placental layer differentiation [3]. In cancer research, overexpression of Plac1 in cervical cancer cells promotes proliferation, migration, and invasion via the mTOR/HIF-1α/Snail pathway [4]. In nasopharyngeal carcinoma cells, Plac1 promotes proliferation, migration, and invasion through the Furin/NICD/PTEN pathway [5]. In head and neck squamous cell carcinoma, Plac1 has a "dual immunosuppressive function" on the tumor microenvironment, is associated with epithelial-mesenchymal transition and tumor invasion, and can be a prognostic predictor [6].

In conclusion, Plac1 is essential for normal placental development. In the context of cancer, its role in promoting tumor progression through various signaling pathways has been revealed by studies. These findings from model-based research, especially in mouse models, contribute to our understanding of Plac1's functions in placental biology and cancer, providing potential targets for cancer immunotherapy.