Therefore, the research team mentioned in the preceding paragraph examined CXCR4 mRNA levels in a series of monophasic localized and metastatic SS specimens and discovered considerably increased expression of the CXCR4 gene in the tumor compared to normal tissue, confirming that CXCR4 promotes the incidence and progression of SS (Pazzaglia et al., 2019). The gene discussed is CXCR4; the disease is neoplasm.