7,12-Dimethylbenz[a]anthracene-induced 'early' squamous cell carcinoma in the Golden Syrian hamster: evaluation of an animal model and comparison with 'early' forms of human squamous cell carcinoma in the upper aero-digestive tract

To test and optimize photodynamic therapy of early cancers in the upper aero-digestive tract and oesophagus, we sought an appropriate animal model, which was found in the 7,12-dimethylbenz[ a ]anthracene-induced early squamous cell carinoma in the Golden Syrian hamster. This chemically induced neoplasm is shown, by histology and immunohistochemistry, to pass through similar stages of early cancer development as its human counterpart. Its time sequence is highly reproducible, leading to a well differentiated carcinoma in situ and microinvasive carcinoma in the hamster cheek pouch over a period of 10 weeks.     

Carcinoma of the perianal gland and associated structures in 1,2-dimethylhydrazine treated mice

Male C57BL/Icrf a^t mice receiving long courses of weekly subcutaneous injections of 8.25 or 12.5 mg/kg, 1,2-dimethylhydrazine (DMH) developed perianal carcinomas as well as tumours at other sites. Tumours of the perianal gland or its associated hair root sheath and overlying skin included sebaceous gland adenocarcinomas, often with squamous metaplasia, analogous to those in the rat ear, and dysplasia, polyp formation and squamous cell carcinomas (SCC). Of 152 mice treated, 88 remained after 30 injections, and 10 out of a total of 14 tumours developed after 30 treatments. Perianal SCC without definite perianal gland association developed in 2 other animals.     

Primary pure squamous cell carcinoma of the thyroid: report and histogenic consideration of a case involving a BRAF mutation

Primary squamous cell carcinoma of the thyroid (SCC-T) is extremely rare. Its clinical presentation is similar to that of anaplastic carcinoma. Metastasis or extension from the head and neck area should be ruled out, as patients with SCC-T have a poorer prognosis than patients who have a thyroid extension from an adjacent tumor. An 87-year-old man presented with a longstanding painless mass in the right thyroid and had experienced 2 months of pain upon swallowing. A right lobectomy was performed with resection of thyroid cartilage, cricoid cartilage, a portion of the first to third tracheal ring and the right neck lymph node. A histological examination revealed pure SCC. The tumor cells showed diffuse immunoreactivity to CK5/6, CK19 and p63. Immunoreactivity to EMA and p53 was focally positive. TTF-1, galectin 3 and thyroglobulin immunoreactivity was restricted to the non-neoplastic thyroid tissue. Both tumor cells and non-neoplastic follicular cells were negative for CD5. The MIB-1 index was 36%. DNA extracted from the tumor identified a BRAF V600E mutation in exon 15 and a BRAF G468A mutation in exon 11, whereas DNA from non-tumorous cells did not contain a mutation. These molecular findings may suggest a direct transformation from papillary carcinoma to SCC-T.     

Expression of beta-adrenergic receptor up-regulation is mediated by two different processes

Mechanisms of up-regulation of beta-adrenergic receptors (beta-ARs) induced by sustained exposure to 10(-8) M nadolol, a non-selective beta-AR antagonist, were examined using mouse cerebrocortical neurons. Nadolol dose- and time-dependently increased [3H]CGP-12177 bindings to the particulate fractions. This increase occurred 6 h and attained its plateau 12 h after the exposure, whereas beta1- and beta2-AR mRNA significantly increased 24 h and attained their plateaus 3 days after the exposure. Scatchard analysis revealed that the increased bindings were due to increase of receptor density. The [3H]CGP-12177 bindings to beta1- and beta2-ARs increased both 12 h and 5 days after the exposure. Although cycloheximide (CHX) decreased the bindings with or without nadolol, the extent of increase of the bindings induced by nadolol was not affected by CHX. Actinomycin D (AD) with nadolol showed no affects on the bindings 12 h after nadolol exposure, while AD treated 6 h after nadolol exposure significantly reduced the bindings 48 h after nadolol exposure. During 24 h after nadolol exposure, the increase in proteins of beta1- and beta2-ARs in the neuronal membrane was due to the increased receptor protein translocation from cytosol to membrane. These results indicate that the up-regulation of beta-ARs induced by nadolol is mediated by, at least, two different processes, one is increase in translocation of receptor proteins from cytosol to membrane with no changes in synthesis of receptor proteins and their mRNA and another is dependent on receptor protein synthesis with increased synthesis of their mRNA.     

Human papillomavirus 8 E6 disrupts terminal skin differentiation and prevents pro-Caspase-14 cleavage

Expression of the betapapillomavirus (betaPV) E6/E7 genes has been shown to impair both keratinocyte differentiation and apoptosis. Especially late-terminal keratinocyte differentiation shares certain aspects with apoptosis, such as fragmentation of DNA and activation of caspases. Here we investigated the disruption of keratinocyte differentiation in organotypic skin (raft) cultures of primary (PHK) and immortalized (N/TERT) human keratinocytes, in particular by human papillomavirus (HPV)8.Immunohistochemical analysis of HPV5 and HPV8 E6/E7-expressing PHK revealed thickening of the rafts and complete absence of stratum corneum formation, even after 18 days of culture. This phenotype was confirmed in N/TERT raft cultures. When expressed separately, the aberrant morphology was observed only in rafts expressing E6, not E7. Immunofluorescence analysis of HPV8 E6 PHK rafts showed an increase in number and size of Filaggrin- and Caspase-14-positive cells in the granular layer. In raft lysates analyzed by western-blot, the presence of pro-Caspase-14 in the differentiated keratinocytes was confirmed, but in the HPV8 E6 rafts none of the Caspase-14 subunits were detected.In conclusion, in the raft system, HPV8 E6 prevented late-terminal keratinocyte differentiation resulting in an accumulation of Filaggrin and pro-Caspase-14-positive cells in the absence of stratification. This differentiation arrest was accompanied by the failure to express Caspase-14 subunits, suggesting absence of Caspase-14 activation and probable abrogation of Filaggrin maturation in HPV8 E6-expressing keratinocytes.     

Transforming growth factor-β enhances invasion and metastasis in Ras-transfected human malignant epidermal keratinocytes

Transforming growth factor-β (TGF-β) is known to act as a tumour suppressor early in carcinogenesis, but then switches to a pro-metastatic factor in some late stage cancers. However, the actions of TGF-β are context dependent, and it is currently unclear how TGF-β influences the progression of human squamous cell carcinoma (SCC). This study examined the effect of overexpression of TGF-β1 or TGF-β2 in Ras-transfected human malignant epidermal keratinocytes that represent the early stages of human SCC. In vitro, the proliferation of cells overexpressing TGF-β1 or TGF-β2 was inhibited by exogenous TGF-β1; cells overexpressing TGF-β1 also grew more slowly than controls, but the growth rate of TGF-β2 overexpressing cells was unaltered. However, cells that overexpressed either TGF-β1 or TGF-β2 were markedly more invasive than controls in an organotypic model of SCC. The proliferation of the invading TGF-β1 overexpressing cells in the organotypic assays was higher than controls. Similarly, tumours formed by the TGF-β1 overexpressing cells following transplantation to athymic mice were larger than tumours formed by control cells and proliferated at a higher rate. Our results demonstrate that elevated expression of either TGF-β1 or TGF-β2 in cells that represent the early stages in the development of human SCC results in a more aggressive phenotype.     

口腔癌前病变及口腔癌中D9S171微卫星位点变化的研究

目的 探讨口腔粘膜癌前病变及口腔鳞癌组织中染色体D9S171微卫星位点变化的情况。方法 使用PCR结合琼脂糖凝胶电泳条带Genetoolsanalysis software分析对35例口腔粘膜癌前病变及15例口腔鳞癌的D9S171位点上的杂合性缺失（LOH）和微卫星不稳定（MSI）进行分析。结果 50例口腔粘膜癌前病变度口腔癌组织中，D9S171位点上21例出现微卫星改变（LOH＋MSI），其中8例标本出现LOH，13倒标本出现MSI。不同临床诊断及病理学分型之间的LOH或MSI检出率经统计学检验无显著性差异（P〉0．05）。结论 D9S171可能为口腔癌前病变癌变过程中的异常基因之一。在口腔癌前病变癌变的发展过程中扮演一定角色。