Differentiation of melanoma from non-cancerous tissue in an animal model using elastic light single-scattering spectroscopy

Cutaneous melanoma is the most serious form of skin cancer and is curable only if it is detected early. The most effective treatment for the melanoma is surgical excision of the lesion. Traditionally, wide margins of excision have been used for effective treatment, but are not always desirable due to increased risk of infection and esthetic reasons. Besides, safe surgical margins of the lesion are not always correlated well with the size of the lesions. We have previously developed a system using elastic light single-scattering spectroscopy to differentiate cancerous tissue from non-cancerous tissue and tested it in vitro. The goal of this study was, therefore, to determine the effectiveness of this system ex vivo by using a mouse model of melanoma. First, a melanoma cell line; B16F10 were injected subcutaneously at right mid flank region of C57BL6 mice (n=5) and allowed to develop for two weeks. Tumors were dissected and spectra were taken on tumor tissue and on normal looking skin tissue that was 10 mm distant from the incision. Since these tumors become markedly necrotic in the middle, spectra of necrotic area was also taken. Slopes of the spectra were positive taken on non-cancerous skin tissues that were later verified by histological examination. On the other hand, it gave negative slopes on melanomas. Increased sizes of the nuclei correlated with the negative slope while smaller nuclei found in non-cancerous tissue gave positive slope. Spectrum taken from necrotic area differed from both cancerous and non-cancerous tissue such that it gave a U-shaped spectrum. These results demonstrate that elastic light single-scattering spectroscopy system can differentiate cancerous tissue from non-cancerous and has potential to be used intraoperatively to determine the surgical margins.