ANPEP and metastatic malignant neoplasm: One method by which metastatic cancer evades the immune system is through genetic or epigenetic mechanisms resulting in the loss of expression of endogenous APM components (Alimonti et al., 2000; Shankaran et al., 2001; Setiadi et al., 2005a; Setiadi et al., 2007a; Setiadi et al., 2008a; Saranchova et al., 2016; Saranchova et al., 2018; Dada et al., 2023).