Expression of Five Target Proteins Related to Human Cytomegalovirus Infection in Brain Metastases of Lung Cancer

Abstract

Background: The links between brain metastases of lung cancer and human cytomegalovirus (HCMV) infection have been controversial for a long time. This study aims to explore the links between brain metastases of lung cancer and HCMV infection from the perspective of expression and detection of HCMV immediate early gene (IE), guanine nucleotide-binding protein 4 (GBP4), CXC chemokine receptor 4 (CXCR4), thyroid transcription factor 1 (TTF1) and epidermal growth factor receptor (EGFR) proteins. Methods: We collected brain metastases specimens and lung primary tumor specimens of a series of patients that have not undergone any treatment. Conventional hematoxylin and eosin staining and immunohistochemical staining of target molecules was performed. We used the ImageJ software to process the average optical density value of immune complexes and GraphPad Prism 8.0.1 to perform image analysis, and the SPSS 22.0 statistics package (t test) to analyze the expression differences of target molecules.Results: Based on five cases of brain metastases and two cases of lung primary tumors, a total of seven samples were investigated. Conventional pathology diagnosis reported four cases of brain metastases of lung adenocarcinoma and one case of brain metastases of mixed small cell lung cancer with adenocarcinoma. Among the 19 molecular immunopathological test samples, only GBP4, related to HCMV infection, and TTF1, related to metastases, were highly expressed in all seven samples. A comparison of the AOD values of the primary lung cancer to the AOD values of brain metastases, yielded statistically significant differences as follows: in Case No.1, GBP4 (p=0.016), EGRF (p<0.001); in Case No. 2, IE (p<0.001), CXCR4 (p=0.005), EGFR (p=0.023), TTF1 (p=0.004). Conclusions: Although TTF1 is known to be a kinesin for brain metastases of lung cancer cells and it is associated with poor survival prognosis, the role of GBP4, which is closely related to HCMV infection and a key protein of brain metastases of lung cancer, remains unknown. The findings provide new knowledge into the role of GBP4 and could provide clues for devising novel strategies for target molecular therapy research in brain metastases of lung cancer in the context of HCMV infection.