Overexpression of cyclin-dependent kinase 4 protein in extramammary Paget's disease.

Cyclin-dependent kinase 4 and 6 (CDK4/6) plays an important role in cell cycle progression, and the CDK4/6-cyclin D1 complex controls the cell cycle transition from G1 phase to S phase. CDK4 is enhanced in several types of cancers and CDK4/6 inhibitors attenuate the proliferation of several types of cancer in vitro/in vivo. The purpose of our study was to investigate the expression pattern of CDK4 and evaluate its clinical importance in extramammary Paget's disease (EMPD). Almost all EMPD tissues were positive for CDK4, and metastatic lesions had a similar immunostaining intensity to primary lesions. In addition, CDK4 protein levels were positively correlated with those of cyclin D1 protein. Taken together, CDK4 may assume a crucial role in EMPD progression.

The expression of EpCAM in extramammary Paget's disease.

Extramammary Paget's disease (EMPD) is a rare skin malignant tumor. The prognosis of EMPD with distant metastasis is poor, however an effective therapy has not yet established. Recently, EpCAM (epithelial cell adhesion molecule, CD326) has attracted attention as both prognostic marker and therapeutic target in several cancers. Besides, EpCAM is an important surface marker of circulating tumor cell (CTC) in the collection of CTC. Thus, the purpose of our study was to examine the expression levels of EpCAM and evaluate the correlation between its intensity of EpCAM and the clinical characteristics of EMPD. The expression of EpCAM in EMPD was examined using immunohistochemistry. Skin samples were obtained from 32 patients with EMPD. We found that almost all EMPD tissues (90.6%, 29/32) were positive for EpCAM. Furthermore, the staining intensity of EpCAM protein negatively correlated with the presence of distant metastasis. Overexpression of EpCAM in EMPD cells suggests that EpCAM may be a novel therapeutic target and the research of CTC may be newly developed in EMPD. Based on these findings, EpCAM may be a meaningful molecule in EMPD.

Hypoxia accelerates the progression of angiosarcoma through the regulation of angiosarcoma cells and tumor microenvironment.

BACKGROUND: Angiosarcoma is a rare malignant tumor with a poor prognosis. It is known that hypoxic condition activates tumor progression in several cancers. Additionally, hypoxic tumor microenvironment accelerates immune escape. However, the presence and significance of hypoxia in angiosarcoma has not been adequately investigated. OBJECTIVE: To study the role of hypoxia in the progression of angiosarcoma. METHODS: The protein level of hypoxia inducible factor-1α (HIF-1α) in angiosarcoma was examined using immunohistochemistry and immunoblotting. To study the effect of hypoxia on tumor progression, cell proliferation, migration, invasion, and tube formation assays were performed in angiosarcoma cells. The influence of tumor cell supernatant in hypoxia from angiosarcoma cells on immune escape and angiogenesis was analysed to investigate the modulatory effect of hypoxia on tumor microenvironment of angiosarcoma. The molecular mechanism related to these results was investigated using immunoblotting and real time RT-PCR. RESULTS: HIF-1α protein was over-expressed in angiosarcoma tissues and cell lines under hypoxic conditions, and there was heterogeneity of oxygen supply in angiosarcoma. Hypoxia enhanced the proliferation, migration, and invasion abilities and inhibited tube formation in angiosarcoma cells. Tumor cell supernatant in hypoxia from angiosarcoma cells activated the monocyte invasion ability, facilitated its differentiation into M2-like macrophages, and suppressed cell-adhesion. These in vitro results were compatible to the pathological findings of angiosarcoma patients. CONCLUSION: Hypoxia plays a major role in progression of angiosarcoma cells by enhancing cell proliferation, migration, and invasion and by modulating the tumor microenvironment.

Chronic sun exposure-related fusion oncogenes EGFR-PPARGC1A in cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) differs from SCC of other organs in its strong association with chronic sun exposure. However, the specific driver mutations in cSCC remain unknown. Fusion genes in established cSCC cell lines (A431 and DJM-1) were predicted by transcriptome sequence, and validated by Sanger sequence, fluorescence in situ hybridization and G-banding. By transcriptome sequencing, we identified fusion gene EGFR-PPARGC1A in A431, which were expressed in 31 of 102 cSCCs. The lesions harboring the fusion gene tended to be located in sun-exposed areas. In vivo cutaneous implantation of EGFR-PPARGC1A-expressing NIH3T3 induced tumors resembling human cSCC, indicating its potent tumorigenicity. NIH3T3 transfected with EGFR-PPARGC1A as well as A431 showed increased cell proliferation activity. With regard to underlying mechanism, EGFR-PPARGC1A protein causes constitutive tyrosine phosphorylation, and induces the phosphorylation of wild-type full-length epidermal growth factor receptor (EGFR) by dimerization. Conversely, the RNAi-mediated attenuation of EGFR or CRISPR/Cas9-mediated knockdown of the fusion gene in A431 led to a decrease in the cell number, and may have therapeutic value. Our findings advance the knowledge concerning genetic causes of cSCC and the function of EGFR, with potential implications for new diagnostic and therapeutic approaches.