Krt18, also known as keratin 18, is one of the most abundant keratins in epithelial and endothelial cells. It has been implicated in multiple biological processes. Although its exact function is still being explored, it has been associated with cell adhesion, migration, and invasion, and may be involved in various signaling pathways such as MAPK/ERK pathway [3,4,5].

In embryo implantation, knockdown of Krt18 in mouse embryos inhibited embryo adhesion and implantation, and in vitro experiments showed that silencing Krt18 disturbed trophoblast migration and invasion, suggesting it plays a crucial role in this process [1]. In cancer research, Krt18 has been found to act as an oncogene in colorectal cancer, gastric cancer, and lung adenocarcinoma. Down-regulation of Krt18 expression depressed cancer cell viability, migration, and invasion in vitro [2,3,6]. Additionally, in gastric cancer, Krt18 was shown to modulate alternative splicing of genes involved in proliferation and apoptosis processes [3].

In conclusion, Krt18 plays essential roles in embryo implantation and cancer-related biological processes. The use of gene-knockout (KO) or conditional-knockout (CKO) mouse models, along with in vitro loss-of-function experiments, has been crucial in revealing its functions in these specific disease areas, providing potential targets for therapeutic intervention in infertility and cancer treatment [1,2,3,6].