Detection of EGFR and COX-2 Expression by Immunohistochemical Method on a Tissue Microarray Section in Lung Cancer and Biological Significance

Background and objective Epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2), which can regulate growth, invasion and metastasis of tumor through relevant signaling pathway, have been detected in a variety of solid tumors. The aim of this study is to investigate the biological significance of EGFR and COX-2 expression in lung cancer and the relationship between them. Methods The expression of EGFR and COX-2 was detected in 89 primary lung cancer tissues, 12 premaliganant lesions, 12 lymph node metastases, and 10 normal lung tissues as the control by immunohistochemical method on a tissue microarray section. Results EGFR protein was detectable in 59.6%, 41.7%, and 66.7% of primary lung cancer tissues, premalignant lesions and lymph node metastases, respectively; COX-2 protein was detectable in 52.8%, 41.7%, and 66.7% of primary lung cancer tissues, premalignant lesions and lymph node metastases, respectively, which were significantly higher than those of the control (P < 0.05). The positive ratios and the levels of the expression of EGFR and COX-2 proteins were closely related to histological type, clinical stage and lymph node metastasis of lung cancer (P < 0.05), but not to histological grade, sex and age (P>0.05). COX-2 expression was related to gross type (P < 0.05). A highly positive correlation was observed between EGFR and COX-2 expression (P < 0.01). Conclusion Overexpression of EGFR and COX-2 may play an important role in the tumorgenesis, progression and malignancy of lung cancer. Detection of EGFR and COX-2 expression might be helpful to diagnosis and prognosis of lung cancer

Development and clinical application of frozen tissue microarray in lung cancer diagnosis

Background and objective Traditional techniques in clinical diagnostic pathology have some limitations. Here we tried to develope frozen tissue microarray as a fast, simple and economical technique. Methods A total of 48 dots frozen tissue microarray were constructed in this study including primary 19 lung cancer samples and 5 normal lung tissue samples from primary lung cancer. Hematoxylin-Eosin and immunohistochemical stains were performed on the sections and we assess the feasibility on morphology and genetic expression. Results The cores on frozen tissue microarray of OCT block were regularly arranged and had no shift and distort. After HE-stained, morphology of the cores was well preserved. They were answered for the request of research.Immunohistochemistry of array slides: we performed immunohistochemistry on the tumor tissue microarray with antibodies for EMA. EMA staining is uniform across the sample and gives the expected cytochylema-associated staining. There is no background staining. We compared the staining of immunohistochemistry on section of frozen tissue microarray to the results on normal slides. The results showed the accord rates were 94.7% (18/19), and there were no significant differences between them each other (P>0.05). Conclusion The frozen tissue microarray is feasible. HE and immunohistochemical stains showing this methodology will be useful for morphology and immunohistochemical based protein analyses

Controlled Synthesis of ZrS₂ Monolayer and Few Layers on Hexagonal Boron Nitride

Group IVB transition metal (Zr and Hf) dichalcogenide (TMD) monolayers can have higher carrier mobility and higher tunneling current density than group VIB (Mo and W) TMD monolayers. Here we report the synthesis of hexagonal ZrS₂ monolayer and few layers on hexagonal boron nitride (BN) using ZrCl₄ and S as precursors. The domain size of ZrS₂ hexagons is around 1–3 μm. The number of layers of ZrS₂ was controlled by tuning the evaporation temperature of ZrCl₄. The stacking angle between ZrS₂ and BN characterized by transmission electron microscopy shows a preferred stacking angle of near 0°. Field-effect transistors (FETs) fabricated on ZrS₂ flakes showed n-type transport behavior with an estimated mobility of 0.1–1.1 cm² V^–1 s^–1