Topical vital staining of human squamous cell carcinoma xenografts in nude mice

We propose a method for visually enhancing residual cutaneous carcinoma in excision sites using topical stains. Utilizing nude mice, topical stains were applied to fresh wound beds containing partially resected human squamous cell carcinoma xenografts. Fifteen of 18 tumors were visually enhanced using topical 1% acridine orange and ultraviolet light, while none of the seven tumors stained with 0.25% dihematoporphyrin ether and ultraviolet light were enhanced. Of the stains tested, only acridine orange proved to visually enhance tumor tissue in a fresh wound bed. This study establishes the concept of direct wound staining as an aid in the excision of cutaneous cancers.