CD44 and breast cancer: From a mechanistic perspective, IL-6 and IL-8 in the SASP work together with tumor cells to induce stromal cells to generate a fibroblast-like morphology, accompanied by the expression and migration of the stemness-related gene CD44, as well as the enhancement of self-renewal and multilineage differentiation, suggesting that IL-6 and IL-8 are relevant to the increased stemness of breast cancer cells, regardless of whether they are alone or coexist.