CCL22 and neoplasm: Factors that are known to promote SCC progression and have been associated with poor prognosis included CCL22, a chemokine that attracts regulatory T cells (Tregs) that shut down the anti-tumor immune response [68]–[71], IL-10, an immuno-regulatory/suppressive cytokine [72]–[75], and IL-4, a prototypical Th2 cytokine [76]–[79].