CXCL8 and neoplasm: CD4 + FoxP3 + Tregs start to accumulate and secrete IL-8 and TGF-β, thus stimulating the expression of cytotoxic T-lymphocyte associated protein 4, T cell immunoreceptor with Ig, and immunoreceptor tyrosine-based inhibitory motif (ITIM) domains, etc. This leads to suppressing the activity of T-lymphocytes and natural killer cells around the tumour environment during the preinvasive stage [21,22].