Immunopathological Profile of Angiogenesis-Related Markers in Subgroups of EGFR-Mutated Lung Adenocarcinomas.

To investigate the expression of angiogenesis-related markers in lung adenocarcinoma (LUAD) harbouring EGFR 19Del mutation and EGFR 21L858R mutation. A descriptive study. Place and Duration of the Study: Department of Oncology, Chongqing University Fuling Hospital, Chongqing, China, from July 2021 to May 2024. Clinicopathological data and tumour specimens were collected from 69 patients with pathologically confirmed LUAD who underwent molecular profiling. Protein expression was assessed using immunohistochemistry (IHC) for angiogenic markers (VEGFA, VEGFR1, VEGFR2) and endothelial markers (CD31, CD34). Statistical analyses were performed using Prism 10. Significant demographic and anatomical differences were observed between the 19Del and 21L858R subtypes. The 21L858R mutation was more frequent in non-smokers and female patients. Anatomically, 19Del tumours predominated in the left lung, while 21L858R tumours were more common in the right lung (p <0.05). IHC analysis revealed higher VEGFR1 expression and significantly elevated CD34+ microvessel density in 21L858R tumours compared to 19Del tumours (p <0.05). EGFR 19Del and 21L858R mutations are associated with distinct expression patterns of VEGFR1 and CD34, which may underlie differential responses to anti-angiogenic therapy and inform future combination treatment strategies. Lung adenocarcinoma, Epidermal growth factor receptor, Vascular endothelial growth factor and receptors, CD31, CD34.