{'fraction_non_alphanumeric': 0.02390710382513661, 'fraction_numerical': 0.012978142076502733, 'mean_word_length': 5.15546218487395, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
7, 12 dimethylbenz(a)anthracene(DMBA)-induced "early" Squamous Cell carcinoma in the Golden Syrian hamster: evaluation of an animal model and comparison with "early" forms of human Squamous Cell car

To improve our knowledge on PDT of human early squamous cell carcinomas of the upper aero-digestive tract and to evaluate new photosensitizers, we have set up the Syrian hamster as an animal model. A 0.5% oily solution of DMBA was applied topically to the left buccal pouch mucosa 3 times weekly. The contralateral buccal pouch served as control. Groups of 5 animals were sacrificed at 6, 8, 10 and 12 weeks from the first applications. Tissue samples of the buccal mucosa were analyzed by histopathologic and immunohistochemical techniques and compared with preneoplastic and neoplastic changes which are seen in the human carcinogenesis of the upper aero-digestive tract. After 6 to 9 weeks from the beginning of the application, we observed different degrees of epithelial dysplasia and after 10 weeks microinvasive carcinomas. The sequence of dysplastic changes to early carcinoma was reproducible in different groups of animals, and they were closely comparable with the human forms of `early' squamous cell cancer. Hyper- and dyskeratosis were present at all stages of tumor development. We are particularly interested in (mu) -invasive tumor forms appearing 10 weeks after the first application because they are potentially amenable to photodynamic therapy.