Col15a1 encodes the alpha chain of collagen XV, a member of the FACIT collagen family [2]. It has anti-angiogenic and anti-tumoral properties and is vital for tissue homeostasis in the liver [2]. COL15A1 also seems to be involved in processes like vasculogenesis, as indicated by its altered expression in endothelial cells with a MAP2K1 mutation related to arteriovenous malformation [3].

In the MMTV-PyMT mouse mammary carcinoma model, inactivation of Col15a1 led to changes in the fibrillar tumour matrix and increased mammary tumour growth, supporting its tumour suppressor function in mammary carcinogenesis [4]. In the context of sarcopenia, Mendelian Randomization analysis suggested that down-regulation of COL15A1 decreased the risk of sarcopenia, indicating its potential as a therapeutic target [1]. In HBV-related HCC, COL15A1 silencing promoted the growth and malignancy of HepG2.2.15 cells, revealing its possible anticancer role [2].

In conclusion, Col15a1 plays crucial roles in multiple biological processes and diseases. Its functions in tumour suppression in breast cancer, as well as its potential relation to sarcopenia and role in HBV-related HCC, have been revealed through in vivo studies using mouse models. These findings contribute to understanding the mechanisms of these diseases and potentially developing new therapeutic strategies.