KRT14 and neoplasm: Tumor angiogenesis in K14-HPV16 mice is dependent on an early influx of mast cells [18] thus, we also stained neoplastic skin sections with toluidine blue to identify infiltrating mast cells, and observed a significant reduction in neoplastic tissue and infiltrating mast cells in HPV16/HoxA5 mice (S3 Fig and Fig 5E) as compared to age-matched HPV16 controls.