Immunological and clinical impact of cancer stem cells in vulvar cancer: role of CD133/CD24/ABCG2-Expressing Cells

Background: Cancer stem cells (CSCs) aretumour-initiating cells with self-renewal properties andchemo/radio-resistance. Regulatory T-cells (Tregs) influenceCSCs through several mechanisms. In different solid tumours,the presence of both cell populations correlated with poorsurvival. In vulvar cancer, little is known regarding biologicalmarkers able to predict patient prognosis. We investigated thepresence and clinical impact of CSCs and infiltrating Treg inprimary vulvar cancer. Materials and Methods: Paraffinembeddedtissue specimens derived from 43 patients withvulvar cancer were analyzed by immunohistochemistry for theexpression of prominin-1 (CD133), CD24, ATP-bindingcassette sub-family G member 2 (ABCG2) (CSC markers) andforkhead box protein P3 (FOXP3) (Treg marker). Results:CD133 expression correlated with younger age at diagnosis(p<0.01), lymph-node metastasis (p<0.05) and larger tumourdiameter (p<0.05). CD133+ tumours showed a high FOXP3+T-cell infiltration. Overall survival and progression-freesurvival were not influenced by the expression of the analyzedbiomarkers. Conclusion: In vulvar cancer, CSCs were morefrequently expressed in younger aged patients and those withaggressive disease. Their presence was also associated withhigh Treg infiltration, which contributes to the generation ofan immunosuppressive milieu.