Igf1, also known as insulin-like growth factor 1, is a crucial peptide hormone. It is closely related to growth hormone (GH) and plays a vital role in growth, development, and metabolism. Igf1 is involved in multiple signaling pathways, such as the IGF1-PI3K pathway which is critical for mediating exercise-induced heart growth and protection [3]. It has broad biological importance, influencing processes from muscle hypertrophy to liver function [4,1]. Genetic models, like KO/CKO mouse models, are valuable for studying Igf1's functions.

In cancer, while GH and Igf1 are not classic oncogenic factors, the GH-Igf1 axis can promote the progression of already transformed cells through the cell cycle [2]. In liver fibrosis, Igf1 and its receptor Igf1R are mainly expressed in liver tissues and play critical roles in DNA damage repair, cell senescence, lipid metabolism, and oxidative stress [1]. In metabolic dysfunction-associated steatotic liver disease (MASLD), raising endogenous GH secretion or administering GH replacement therapy enhances Igf1 production, reducing steatosis and liver injury [5].

In conclusion, Igf1 is essential for normal growth, development, and metabolism. Model-based research, especially through Igf1 KO/CKO mouse models, has revealed its role in cancer progression, liver fibrosis, and MASLD. Understanding Igf1's functions provides insights into the mechanisms of these diseases and may suggest novel therapeutic approaches.