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Background and purpose: Mortality rate from gastric cancer is growing in the world. Nowadays, in many cancers, between cancer development and changes in EGF receptor expression levels there is a very precise relationship. Perhaps one of the best known of these changes in gastric cancer is over expression of Her1 & 2 receptors. This study investigated the expression rate of these two receptors in gastric locally advanced adenocarcinoma, and its correlation with survival of patients. Materials and methods: The samples include 130 paraffin blocks of patients with gastric cancer in Imam Khomeini Hospital in Sari 1383-88. 4 micron sections of tissue blocks were prepared and placed on slides. Then slides were deparaffinized with xylene and dehydrated using alcohol. The endogenous peroxidase activity was inhibited. Her2 Antibody is located on them. Finally, they were stained with hematoxylin. Results: Her1 marker only in 23 samples (17.6 %) and Her2 marker only in 20 samples (15.4 %) were positive. Accompanying these two markers in 9 patients (6.9 %) was also seen simultaneously. The survey marker Her2 based on sex revealed in 91 male patients, only in 11 cases (11.6 %) and in 39 women only 9 cases (23 %) were positive Conclusion: Expression levels of Her1 marker increased with increasing disease stage. These findings may indicate the diagnostic value of this marker in patients with gastric adenocarcinoma. Probably, the rate of HER1 and HER2 receptors expression is associated with invasion and survival of patients.

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Background and purpose: Antibody phage display library is a powerful in vitro technology for production of recombinant antibody fragments against a wide variety of antigens. However, the presence of insert-free clones in the phage libraries limited the specific enrichment of antibody fragments in many studies. The aim of this study was to protein A-aided recovery of insert-containing phages in antibody phage display library. Materials and Methods: Tomlinson antibody library was prepared according to the standard protocol. Three rounds of panning were performed in two independent groups on VERO/HER2 cells, considering a step of protein A-aided phage precipitation at the end of each round only in one group. The efficiency of this method was evaluated on the selected clones using PCR and phage-Elisa. Results: The results of PCR showed that 87% of clones contained insert after three rounds of panning using protein A-recovered phages while in the control group only 41% of clones contained insert. Also, the results of phage-ELISA showed specific enrichment of anti-HER2 antibodies in protein A-treated group. Conclusion: This method provided a simple and effective way for selective enrichment of antibody fragments in the phage display antibody libraries.

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Background and purpose: Breast cancer is the second cause of mortality among women. HER2, a member of the epidermal growth factor receptor family, is overexpressed in approximately 25% of breast cancer cases. This receptor represents a valuable therapeutic target in the management of breast cancer. For the treatment of HER2-positive breast cancer, several agents, including trastuzumab (Herceptin), have been approved. Herceptin is a monoclonal antibody capable of binding to the HER2 receptor. A single-chain variable fragment (scFv) derived from Herceptin can also be utilized in the development of immunotoxins targeting HER2-positive cancer cells. Shiga toxins are bacterial exotoxins commonly produced by Shigella dysenteriae and certain strains of Escherichia coli. The A subunit of Shiga-like toxin 2 (Stx2A) is a potent cytotoxic agent with the potential to kill cancer cells.
Materials and methods: In this insilico study, we employed bioinformatics tools to design an immunotoxin composed of a HER2-specific single-chain variable fragment (scFv) and the A subunit of Shiga-like toxin 2. To construct the immunotoxin, the amino acid sequences of the scFv and Shiga-like toxin 2 subunit A were joined via a peptide linker. The secondary structure, physicochemical properties, solubility, and potential allergenicity of the construct were predicted. The tertiary structure of the immunotoxin was modeled, refined, and evaluated. Protein-protein docking was performed to assess immunotoxin-receptor binding, and molecular dynamics simulations were used to evaluate immunotoxin stability.
Results: According to the findings, the designed construct appears to be a stable protein with adequate solubility, non-allergenic properties, and a structurally favorable configuration for binding to HER2.
Conclusion: In conclusion, the designed construct demonstrates potential for the production of a HER2-targeted immunotoxin. However, further validation through comprehensive in vitro and in vivo immunological assays is necessary to confirm the efficacy and therapeutic potential of the construct.