CXCR1 and breast cancer: Generally, the CXCL8-CXCR1/2 axis plays impact roles on formation, development or invasion of CSCs in colon cancer (Luo et al., 2018; Fisher et al., 2019; Kim et al., 2021), breast cancer (Choi et al., 2009), glioblastoma (Zhou et al., 2014; McCoy et al., 2019), clear cell renal cell carcinoma (ccRCC) (Corrò et al., 2019), pancreatic cancer (Chen et al., 2014), hepatocellular carcinoma (HCC) (Kahraman et al., 2019), lung cancer (Shimizu and Tanaka, 2019), bladder cancer (Zhou et al., 2021) and esophageal carcinoma (Huang et al., 2017).