Hematopoietic stem cells: do they have a role in keloid pathogenesis?

Keloids are slow growing neoplasms characterized by benign proliferation of fibroblasts that is due, at least in part, to altered cytokine profiles. Stem cells were claimed to play a role in skin tumor development. However, their role in keloid formation is unclear. The current study investigated the immunoreactivity of CD34 and c-KIT antibodies in 30 cases with keloid lesions together with normal skin biopsies of 30, sex and age-matched subjects representing the control group. Examined keloid sections showed positive dermal stromal immunoreactivity for CD34 in 76.7% of cases. CD34 expression intensity and H score were upregulated in keloid tissue relative to normal skin (p < 0.0001, p = 0.0002, respectively) and in perilesional relative to lesional tissue (p = 0.03, p < 0.001, respectively). c-KIT showed positive dermal stromal expression in all cases. Dermal c-KIT expression intensity and H score were upregulated in keloid tissue relative to normal skin (p < 0.008, p < 0.001, respectively) and in perilesional relative to lesional tissue (p < 0.0001, p < 0.001, respectively). Lesional skin showed more staining of basal keratinocytes when compared to perilesional tissue (p < 0.0001). Hematopoietic stem cells may share in keloid pathogenesis. Further studies are warranted to gain firmer conclusion about the exact role played by these cells and the significance of their perilesional accumulation. The future therapy of keloid scars may have to target this stem cell population in order to deprive these tumors of their regenerative cell pools.