BMP4 and obesity due to melanocortin 4 receptor deficiency: This aligns with prior reports linking BMP4 to metabolic diseases, including obesity, diabetes, and hepatic steatosis (Son et al., 2011; Wang et al., 2017; Modica et al., 2016; Peng et al., 2019), suggesting that BMP4 may facilitate PAAD tumorigenesis via metabolic regulation.