S U M M A R YThe epidermal growth factor receptor (EGFR) is highly expressed in a variety of solid malignant tumors and its expression has been correlated with disease progression and poor survival. With the advent of targeted therapies, especially IMC-C225 (Cetuximab), a monoclonal antibody (MAb) directed against the EGFR, there is an increasing interest in immunohistochemistry (IHC)-based EGFR screening methods using paraffin-embedded tumor specimens to select cancer patients eligible for treatment with Cetuximab. With the EGFRpharmDX kit, a complete assay for demonstration of EGFR is now available. Because no information about the preservation of the EGFR under various conditions of fixation is available, we performed a prospective study on a panel of commonly used fixatives to determine optimal tissue preservation protocols. The stability of the epitope on cut tissue sections stored for a period up to 24 month was also tested using material originating from patients with head and neck cancer, non-small-cell lung carcinomas, and colorectal adenocarcinomas. Depending on the fixative used and the time of storage of cut tissue sections, a variation in the determined level of EGFR expression was demonstrated compared with the most optimal fixation procedure.

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Many analytical methods are used to measure the antioxidative activity of substances yet little is known about the comparability of the test results between laboratories. After an initial evaluation of a broad range of methods conducted by one laboratory, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the trolox equivalent antioxidant capacity (TEAC) assay, the lipid assay (or 2,2'-azobis(2-aminepropane) (ABAP) assay) and the thiobarbituric acid (TBA) assay were selected to be evaluated in the interlaboratory study. The antioxidative potentials of trolox, tocopherol, lipochroman-6, ascorbic acid, 4-methyl-brenzcatechin, and/or 3,5-di-tert-butyl-4-hydroxytoluene (BHT) were assessed using each of the methods. These methods were then evaluated in respect of their reproducibility and classification properties. Based on the results of this study, the DPPH assay followed by the TEAC assay yielded the best results based on reproducibility and sensitivity both within one laboratory and between laboratories. The results of the interlaboratory study were then compared with the single center results obtained from the commercially available photochemolumiescence (PCL) kit. To assess the transferability of chemical data to biological systems, they were also compared with the single center results obtained using the cell-based Dichlorodihydrofluoresceine (DCFH) assay.

The murine IgG2a monoclonal antibody (mAb) EMD 55900 was produced against the human epidermoid carcinoma cell line A431, with binding occurring to the polypeptide chain of the external domain of human epidermal growth factor receptor (EGF-R). In the present clinical study, 12 patients with advanced squamous cell carcinoma of the larynx or hypopharynx received a single dose of either 20, 100 or 400 mg EMD 55900 3 days prior to laryngectomy and neck dissection. Clinical signs and laboratory parameters of toxicity, development of human anti-mouse antibodies, and mAb plasma concentrations were monitored. In tumor specimens studied from primary tumors and lymph node metastases, expression of EGF-R, distribution of EMD 55900, and occupation of EGF-R by EMD 55900 (double staining) were determined by immunohistochemistry. Single-dose administration of EMD 55900 was very well tolerated in all patients, and good (100 mg) to excellent (400 mg) homogeneous binding of mAb to EGF-R was obtained in the advanced laryngeal and hypopharyngeal carcinomas studied.