The concentration of CXCL7 is significantly higher in the blood draining tumors from patients with lung cancer compared to peripheral blood, and the CXCL7 gradient was correlated with the absolute number of helper T cells (r = 0.49, p = 0.03) (Yee et al., 2009; Spaks, 2017). Here, PPBP is linked to lung carcinoma.