CCR4 and neoplasm: Supplementary Figure 4 shows illustrative examples of the solar elastosis grading and corresponding IHC staining performed on the cuSCC tumors. Among the 24 cuSCC tumors investigated by IHC staining, higher levels of solar elastosis (i.e., cumulative sun damage) measured in the adjacent normal tissue were significantly associated with higher proportions of CCR4-expressing T cells, as well as CCR4 and FoxP3 co-expressing Tregs in the tumor (Table 2).