Neoplastic transformation and angiogenesis in the thymus of transgenic mice expressing SV40 T and t antigen under an l‐pyruvate kinase promoter (SV12 mice)

Abstract

Using several techniques, we have assessed morphological characteristics of a malignant thymic tumour in SV12 transgenic (Tg) mice expressing SV40 T and t antigens under control of an L-PK promoter. We describe the development of a carcinoma originating from thymic hyperplasia and followed by the formation of a benign tumour composed chiefly of medullary epithelial cells expressing the transgene and of lymphocytes, a pathology very rarely reported in mice. Our study of the SV12 Tg mice represents the first description of a model of a pure malignant thymic tumour associated with extensive angiogenesis maintained in numerous descendants. The formation of a large tumoral neovascular network, observed here, has never been described in human and/or experimental thymic tumours. Tumoral transformation and angiogenesis are demonstrated by immunolabelling with antibodies against various cytokeratins (CKs) of different molecular weights, vascular endothelial cell markers and VEGF/receptor-2 (Flk-1) present on the neovascular endothelial cells. Different points raised by the originality of this model are discussed. These include the medullary nature of the cells expressing the SV40 transgene and their relationship with the tumoral development. The subset of different molecular weight CK components and their modifications are also considered, as well as the presence of type IV epithelial cells, progenitors of medullary epithelial cells. Finally, the cell signals involved in angiogenesis and the possible action of an angiogenic factor, probably secreted by the tumoral cells themselves, are discussed.

Serum cytokine and chemokine profiles in patients with myasthenia gravis

“…In this study, no patients with thymic hyperplasia were involved, and there were no differences in VEGF levels between MG patients with thymoma and MG patients without thymoma. Hence, we could not substantiate whether or not VEGF increased due to the active neoangiogenic processes observed in the MG patients with thymic abnormality [20,21]. To date, VEGF levels have not been reported in patients with MG.…”

Investigation of Cross-Contamination and Misidentification of 278 Widely Used Tumor Cell Lines

“…Our findings showed evidence of 46.9% (60/128) cross-contamination was caused by HeLa, affecting 31 cell lines, which were purported to have been established from 10 types of tumor (colon, liver, breast, stomach, lung, nasopharynx, tougue, laryngeal, salivary gland and bronchia) and 3 types of normal tissue (lung, intestine and liver). The bladder cancer cell line T24 was established in 1972 and has contributed to several cell line cross-contamination [20, 21]. We identified three separate instances by T-24 in two laboratories, which might have used the established cell lines: LNCaP and EJ.…”