Down-regulation of keratin 4 and keratin 13 expression in oral squamous cell carcinoma and epithelial dysplasia: a clue for histopathogenesis.

AIMS: This study aimed to identify relevant keratin subtypes that may associate with the pathogenesis of oral epithelial neoplasms. METHODS AND RESULTS: Expression of all the keratin subtypes was examined by cDNA microarray analysis of 43 oral squamous cell carcinoma (OSCC) cases. Immunohistochemical expression of the major keratins was examined in 100 OSCC and oral epithelial dysplasia (OED) cases. Many changes in keratin expression were observed and, significantly, consistent down-regulation of keratin 4 (K4) and K13 expression was observed. Aberrant expression of K4 and K13 was associated with morphological changes in the affected oral epithelium. Experiments with cell cultures transfected with various keratin subtypes suggested that alterations in keratin subtype expression can cause changes in cell shape and movement. CONCLUSIONS: Aberrant expression of K4 and K13, which are the dominant pair of differentiation-related keratins in oral keratinocytes, indicates dysregulation of epithelial differentiation in OSCC and OED. These keratins, especially K4, may be useful for pathological diagnosis. We propose that the aberrant expression of K4 and K13 and concomitant up-regulation of the other keratins may be one of the causative factors for morphological alterations in the affected epithelium.

Dietary salt regulates the phosphorylation of OSR1/SPAK kinases and the sodium chloride cotransporter through aldosterone.

Pseudohypoaldosteronism type II (PHAII) is caused by mutations in the WNK1 and WNK4 genes (WNK with-no-lysine kinase). In a mouse model of this disease where a mutant of Wnk4 D561A was knocked in, increased phosphorylation of the sodium chloride cotransporter (NCC) was found and the transporter was concentrated on the apical membrane of the distal tubules. In addition, we recently found that other kinases, such as the oxidative stress response kinase-1/STE20/SPS1-related proline alanine-rich kinase (OSR1/SPAK), also showed increased phosphorylation in these mice. Here we determined whether this kinase cascade is regulated by dietary salt intake. We found that the phosphorylation states of NCC and OSR1/SPAK were increased by low-salt diets and decreased by high-salt diets; a regulation completely lost in the knock-in mice. Increased phosphorylation was reversed by spironolactone and this decreased phosphorylation was reversed by administration of exogenous aldosterone. These studies suggest that that the WNK-OSR1/SPAK-NCC cascade may be a novel effector system of aldosterone action in the kidney.

Fusion between CIC and DUX4 up-regulates PEA3 family genes in Ewing-like sarcomas with t(4;19)(q35;q13) translocation.

Ewing's family tumors (EFTs) are highly malignant tumors arising from bone and soft tissues that exhibit EWS-FLI1 or variant EWS-ETS gene fusions in more than 85% of the cases. Here we show that CIC, a human homolog of Drosophila capicua which encodes a high mobility group box transcription factor, is fused to a double homeodomain gene DUX4 as a result of a recurrent chromosomal translocation t(4;19)(q35;q13). This translocation was seen in two cases of soft tissue sarcoma diagnosed as Ewing-like sarcoma. CIC-DUX4 exhibits a transforming potential for NIH 3T3 fibroblasts, and as a consequence of fusion with a C-terminal fragment of DUX4, CIC acquires an enhanced transcriptional activity, suggesting that expression of its downstream targets might be deregulated. Gene expression analysis identified the ETS family genes, ERM/ETV5 and ETV1, as potential targets for the gene product of CIC-DUX4. Indeed, CIC-DUX4 directly binds the ERM promoter by recognizing a novel target sequence and significantly up-regulates its expression. This study clarifies the function of CIC and its role in tumorigenesis, as well as the importance of the PEA3 subclass of ETS family proteins in the development of EFTs arising through mechanisms different from those involving EWS-ETS chimeras. Moreover, the study identifies the role of DUX4 that is closely linked to facioscapulohumeral muscular dystrophy in transcriptional regulation.

p53 Mutation analysis of low-grade dysplasia and high-grade dysplasia/carcinoma in situ of the esophagus using laser capture microdissection.

OBJECTIVES: The aim of this study was to determine the prevalence and to analyze the characteristics of p53 point mutation in esophageal intraepithelial lesions. METHODS: p53 Immunohistochemical and genetic analyses were performed on histopathologically and morphometrically diagnosed lesions. Laser capture microdissection samples were used for increased accuracy. RESULTS: Of the 70 lesions studied, 21 were high-grade dysplasia/carcinoma in situ (HGD/CIS), 21 low-grade dysplasia (LGD), 16 reactive atypical epithelia (RAE) and 12 normal epithelia (NE). Immunohistochemical staining showed p53 protein accumulation in 86% (18/21) of HGD/CIS, 81% (17/21) of LGD, and in none of RAE and NE. p53 point mutation was detected in 71% (15/21) of HGD/CIS, 67% (14/21) of LGD, but in none of RAE and NE. Of HGD/CIS and LGD with p53 protein accumulation, similar percentages had mutations: 83% (15/18) and 82% (14/17), respectively. Of lesions with mutations, 72% (21/29) had mutations at hot spots such as codons 238, 248, 273 and 282. CONCLUSIONS: p53 Point mutation prevalent in HGD/CIS was also present in a large number of LGD. This is strong evidence that LGD is a neoplastic lesion and that p53 point mutation is deeply involved in esophageal carcinogenesis.

Importance of thymidine phosphorylase expression in tumor stroma as a prognostic factor in patients with advanced colorectal carcinoma.

Thymidine phosphorylase (TP) is a unique enzyme involved not only in angiogenesis, but in 5-fluorouracil (5-FU) metabolism as well. TP is produced by both tumor and stromal cells. The aim of this study was to reveal the clinical implication of TP localization in tumor tissues. Advanced colorectal cancer specimens (n=97) were prepared for immunohistochemical staining using monoclonal antibodies against TP, p53, vascular endothelial growth factor (VEGF), factor VIII, CD68 and thymidylate synthase (TS). Clinicopathological factors and the clinical prognosis were examined for each indicator. High tumor TP expression and high stromal TP expression were observed in 38% (36/95 cases) and 49% (47/95 cases) of the cases, respectively. High tumor TP expression tended to correlate with microvessel density (MVD) (p=0.0511). Among patients who underwent curative resection, those with high stromal TP expression had a favorable prognosis (p=0.0127). High stromal TP status was also a strong prognostic factor in the group receiving adjuvant 5-FU derivatives (p=0.0222). TP produced by tumor cells has a stimulatory effect on tumor angiogenesis, while that produced by stromal cells plays an entirely different role. The latter may enhance the anticancer effect of 5-FU via its catalyzed function.

[A case of intraocular malignant lymphoma diagnosed by immunoglobulin gene rearrangement and translocation, and IL-10/IL-6 ratio in the vitreous fluid].

BACKGROUND: The diagnosis of primary intraocular lymphoma is difficult in many cases even with conventional cytological tests using vitreous samples. Recently new diagnostic tests, such as microdissection and polymerase chain reaction (PCR) and measurement of cytokines using intraocular samples, have been applied to the diagnosis of the disease. We report here a case where we used the new diagnostic tests and the results aided us to make a diagnosis of intraocular lymphoma. CASE: A 68-year-old woman with an initial diagnosis of bilateral idiopathic uveitis with steroid-resistant vitreous opacities underwent a vitreous biopsy. The cytological examinations of the vitreous samples revealed class III. The microdissection and PCR using the vitreous samples detected IgH rearrangement gene in the third framework (FR3A), the complementary determining region 3 (CDR3) of the VH region and Bcl-2-associated translocation. The interleukin (IL)-10 to IL-6 ratio in the vitreous fluid was greater than 100. Because the results of the examinations strongly suggested intraocular lymphoma, the patient was treated with radiation and chemotherapy. One month after the therapy, however, the patient developed multiple metastatic lesions in the brain. The clinical course of the patient together with the new diagnostic results of examinations led to a diagnosis of intraocular lymphoma. CONCLUSION: A combination of tests, such as conventional cytology, microdissection, and PCR, and cytokine assay using intraocular biopsy samples, is useful to make a diagnosis of intraocular lymphoma.