CD44 and cancer: Furthermore, future studies for protein expression on breast tumors by immunohistochemistry may consider developing double-staining for the expression of CXCL5 and ADSC markers, such as CD44, CD90, and CD10531,32, or the expression of CXCL5 and tumor markers for fast replicating cancer cells, such as Ki67 and proliferating cell nuclear antigen (PCNA)42,43, to differentiate the expression loci of CXCL5 in the breast tumor microenvironment.