Depending on the stage of the disease, dysregulation and significant shifts in the expression of chemokine–chemokine receptor axis genes, such as CXCL9, CCL18, and CCR7, mediate the progression of MF from early, skin-limited infiltrates to an advanced, disseminated cancer with systemic manifestations [62,63]. The gene discussed is CXCL9; the disease is mycosis fungoides.