Density and Polarization States of Tumor-Associated Macrophages in Human Cutaneous Squamous Cell Carcinomas Arising in Solid Organ Transplant Recipients.

Background: Solid organ transplant recipients (SOTRs) are 100 times more likely to develop cutaneous squamous cell carcinoma (SCC) with greater metastatic propensity compared with the general population, likely due to chronic immunosuppression and adverse drug effects on keratinocytes. Tumor-associated macrophages (TAMs) play critical roles in malignancies, either aiding in eradication of malignant cells or promoting tumor growth.

Objective: The authors examined whether TAM density and polarization states differ between SOTRs and nontransplant individuals.