SFRP2 and neoplasm: It is able to induce apoptosis of various tumor cells in vitro by regulating many signaling pathways, such as caspase family proteins, transforming growth factor (TGF) receptor, Smad 4 protein, and secreted frizzled-related protein 2 (SFRP2) (Senthilkumar and Kim, 2014; Ma et al., 2021).