Exploring the conformational dynamics and thermodynamics of EGFR S768I and G719X + S768I mutations in non-small cell lung cancer: An in silico approaches.

Non-small cell lung cancer (NSCLC) is often driven by mutations in the epidermal growth factor receptor (EGFR) gene. However, rare mutations such as G719X and S768I lack standard anti-EGFR targeted therapies. Understanding the structural differences between wild-type EGFR and these rare mutants is crucial for developing EGFR-targeted drugs. We performed a systematic analysis using molecular dynamics simulations, essential dynamics (ED), molecular mechanics Poisson-Boltzmann surface area, and free energy calculation methods to compare the kinetic properties, molecular motion, and free energy distribution between wild-type EGFR and the rare mutants' structures G719X-EGFR, S768I-EGFR, and G719X + S768I-EGFR. Our results showed that S768I-EGFR and G719X + S768I-EGFR have higher global and local conformational flexibility and lower thermal and global structural stability than WT-EGFR. ED analysis revealed different molecular motion patterns between S768I-EGFR, G719X + S768I-EGFR, and WT-EGFR. The A-loop and αC-helix, crucial structural elements related to the active state, showed a tendency toward active state development, providing a molecular mechanism explanation for NSCLC caused by EGFR S768I and EGFR G719C + S768I mutations. The present study may be helpful in the development of new EGFR-targeted drugs based on the structure of rare mutations. Our findings may aid in developing new targeted treatments for patients with EGFR S768I and EGFR G719X + S768I mutations.

Unique characteristics of G719X and S768I compound double mutations of epidermal growth factor receptor (EGFR) gene in lung cancer of coal-producing areas of East Yunnan in Southwestern China.

BACKGROUND: The principal objective of this project was to investigate the Epidermal Growth Factor Receptor (EGFR) gene mutation characteristics of lung cancer patients, which can provide a molecular basis for explaining the clinicopathological features, epidemiology and use of targeted therapy in lung cancer patients in the coal-producing areas of East Yunnan. METHODOLOGY: We collected 864 pathologically confirmed lung cancer patients' specimens in First People's Hospital of Qujing City of Yunnan Province from September 2016 to September 2021. We thereafter employed Next Generation Sequencing (NGS) technology to detect all exons present in the EGFR gene. RESULTS: The overall mutation frequency of the EGFR gene was 47.22%. The frequency of EGFR gene mutations in the tissue, plasma, and cytology samples were found to be 53.40%, 23.33%, and 62.50%, respectively. Univariate analysis indicated that the coal-producing areas and Fuyuan county origin were significantly associated with relatively low EGFR gene mutation frequency. Female, non-smoking history, adenocarcinoma, non-brain metastasis, and tissue specimens were found to be related to high EGFR gene mutation frequency. Multivariate logistic regression analysis suggested the lung cancer patients in the central area of Qujing City, stage Ia, non-coal-producing areas, non-Fuyuan origin, and non-Xuanwei origin were more likely to develop EGFR gene mutations. The most common mutations were L858R point mutation (33.09%) and exon 19 deletion (19-del) (21.32%). Interestingly, the mutation frequency of G719X (p = 0.001) and G719X + S768I (p = 0.000) in the coal-producing areas were noted to be more significant than those in non-coal-producing regions. CONCLUSION: This findings of this study might be important in establishing the correlation between routine using NGS for EGFR gene mutation diagnosis and clinical practice in the lung cancer patients.

[The correlation between BRAF mutations, RET/PTC rearrangements and platelet-derived growth factor B expression in papillary thyroid carcinomas].

OBJECTIVE: To investigate the prevalence of BRAF T1799A mutation and RET/PTC rearrangement in Qingdao and detect the expression of platelet-derived growth factor B (PDGF-B) in order to investigate the correlation between gene mutation and PDGF-B. METHODS: Fresh tissue from 48 papillary thyroid carcinomas (PTC) patients was examined for BRAF mutation RET rearrangements (RET/PTC1 and RET/PTC3) by PCR, followed by direct-sequence analysis. The expression of PDGF was analyzed by immunohistochemistry. RESULTS: Among the 48 patients, 14 (29.2%) were micro PTC; 18 (37.5%) had BRAF T1799A mutations and 23(47.9%) had RET/PTC rearrangement. There were 17 (35.4%) cases of RET/PTC1 and 6 (12.5%) of RET/PTC3, with no multiple rearrangements. Both BRAF T1799A mutation and RET/PTC rearrangement were present in 6 (12.5%) cases of non-micro PTC. The level of PDGF-B expression in BRAF T1799A positive was higher than that in the negative, and the level of PDGF-B expression in RET/PTC3 was higher than that in RET/PTC1 (P < 0.05). The more advanced neoplasm stage was, the stranger PDGF-B expression was. CONCLUSIONS: The incidence of BRAF T1799A mutation and RET/PTC rearrangement is higher in Qingdao. BRAF T1799A mutation and RET/PTC3 rearrangement in patients suggests a poorer prognosis than the negative one. The BRAF T1799A mutation and RET/PTC3 rearrangement may strengthen the expression of PDGF-B. Both variations suggest a poor prognosis.