PTK2B and neoplasm: CCL5 expression is associated with CDDP resistance, due to the increased secretion of CC chemokines from both: autocrine manner, where the cell sends signals to itself through the secretion of ligands that bind to receptors on its own surface [30], and the tumor microenvironment (paracrine regulation) through the activation of pathways, such as Proline-rich tyrosine kinase 2 (PYK2) and Signal transducer and activator of transcription 3 (STAT3) [31, 32].