Dear Editor,

LIF, a multi-functional cytokine, is frequently overexpressed in many human cancers, including breast, colorectal, and pancreatic cancers (Liu et al., 2013; Li et al., 2014; Yu et al., 2014; Pascual-Garcia et al., 2019; Shi et al., 2019; Wang et al., 2019). LIF overexpression is frequently associated with poor prognosis in human cancers (Liu et al., 2013; Li et al., 2014; Yu et al., 2014). LIF functions through binding to LIF receptor complex composed of LIF receptor (LIF-R) and glycoprotein gp130 (Taga and Kishimoto, 1997; Heinrich et al., 2003; Watanabe et al., 2006). LIF overexpression induces activation of several oncogenic signaling pathways in a cell/tissue type-specific manner, including STAT3, PI3K/AKT, and mTOR, which in turn promotes proliferation, metastasis, and therapeutic resistance of cancer cells (Liu et al., 2013; Li et al., 2014; Yu et al., 2014; Shi et al., 2019). Recent studies have suggested that LIF is a potential important target for cancer therapy, especially for cancers with LIF overexpression. LIF neutralization antibodies (LIF neu Abs) have been reported to block LIF signaling and largely abolish the promoting effect of LIF on cancer progression (Li et al., 2014; Yue et al., 2016; Shi et al., 2019).