Expression profiles of p63, p53, survivin, and hTERT in skin tumors.

BACKGROUND: p63 is a p53 homolog and a marker expressed in replicating keratinocytes. Survivin is a recently characterized inhibitor of apoptosis protein that is abundantly expressed in most solid and hematologic malignancies. Telomerase reverse transcriptase (TERT) is the major determinant of human telomerase activity, and its expression is indicative of unlimited replication. We herein evaluated the expression profiles of p63, p53, survivin, and hTERT in usual skin cancers, including squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) and putative preneoplastic epidermal lesions, including actinic keratosis (AK), Bowen's disease, and porokeratosis. METHODS: Immunohistochemistry using antibodies against p63, p53, survivin, and hTERT was performed. Semi-quantitative evaluation (-, +, 2+, 3+) was carried out. RESULTS: BCCs showed diffuse p63 expression and SCCs heterogeneous p63 expression with negativity in terminally differentiated squamous cells. All preneoplastic epidermal lesions showed p63 expression in all cell layers. p53 was found in seven of 10 cases of BCCs, all 10 cases of SCCs, and nine of 10 cases of Bowen's disease. AK and porokeratosis revealed focal to moderate p53 expression. Survivin was found in eight of 10 cases of SCCs and eight of 10 cases of Bowen's disease. Six of 10 cases of BCCs revealed weak survivin positivity. AK and porokeratosis showed survivin expression confined to the basal layer. hTERT expression was found in most cases of skin cancers and preneoplastic lesions. CONCLUSIONS: p63 expression may be a marker of basal/progenitor cells and a diagnostic marker in skin tumors. p63 expression is not related to p53 expression in these tumors. This study points to a putative role of survivin and hTERT in the development of certain skin cancers. In addition, our data support the concept of porokeratosis being a premalignant condition.

Expression of osteoprotegerin and RANK ligand in breast cancer bone metastasis.

Bone destruction is primarily mediated by osteoclastic bone resorption, and cancer cells stimulate the formation and activation of osteoclasts next to metastatic foci. Accumulating evidences indicate that receptor activator of NF-kB ligand (RANKL) is the ultimate extracellular mediator that stimulates osteoclast differentiation into mature osteoclasts. In contrast, osteoprotegerin (OPG) inhibits osteoclast development. In order to elucidate a mechanism for cancer-induced osteoclastogenesis, cells from a human breast cancer line, MDA-MB-231, were directly co-cultured with ST2, MC3T3-E1, or with primary mouse calvarial cells. Osteoclast-like cells and tartarate resistant acid phosphatase (TRAP) activities were then quantitated. We examined these cell lines and samples from breast cancer by RT-PCR for the expressions of OPG and RANKL mRNA. Compared to controls, co-culture of MDA-MB-231 cells with stromal or osteoblastic cells induced an increase in number of osteoclasts and TRAP activities. MDA-MB-231 cells alone or breast cancer samples did not express RANKL mRNA. However, co-culture of these cancer cells with stromal or osteoblastic cells induced RANKL mRNA expression and decreased OPG mRNA expression. These experiments demonstrate that direct interactions between breast cancer and stromal or osteoblastic cells induce osteoclastogenesis in vitro through modulating RANKL expression.

Immunoreactivity of CD99 in stomach cancer.

CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.

Expression of Cyclooxygenase-2 Protein in Gastric Carcinogenesis.

PURPOSE: The increased expression of cyclooxygenase (COX)-2 has been implicated in the development and progression of human cancers. We investigated COX-2 expression in normal, gastric adenomas and adenocarcinomas. MATERIALS AND METHODS: COX-2 protein was assayed in gastrectomy and biopsy specimens, from 68 gastric adenocarcinomas, 40 gastric adenomas and 35 normal gastric tissues, by immunohistochemistry, and 32 specimens of normal and adenocarcinomas by western blot analysis. Correlation between COX-2 expression and various clinicopathological factors were studied in the gastric adenocarcinoma. RESULTS: COX-2 protein expression in epithelial cells was increased in 6/40 (15%) of the adenomas and 55/68 (80.9 %) of the adenocarcinomas, while normal mucosa was not expressed. COX-2 expression was increased in differ-entiated gastric carcinomas compared with those in the undifferentiated group (p<0.05). The expression of COX-2 protein was unrelated to tumor size, depth of tumor invasion and the presence of lymphatic or vascular invasions. Western blot analysis showed the enhanced expression of the COX-2 protein (23 out of 32)(71%) in gastric carcinomas compared to that of normal gastric mucosal epithelium. CONCLUSION: The above results indicated that the expression of COX-2 protein occurs in dysplastic epithelium and gastric carcinomas, which suggests COX-2 expression may contribute to tumor formation.