Objective To analyze ethnic differences in mutations of the PIK3CA and TP53 genes among breast cancer patients from the Han, Tibetan, and Hui ethnic groups in Qinghai, China, and their associations with clinicopathological characteristics. Methods A total of 382 breast cancer tissue samples were retrospectively collected from surgical patients (Jan 2020−Dec 2022), comprising 200 Han, 93 Tibetan, and 89 Hui ethnicity. Mutations in PIK3CA (E542K, H1047R, and E545K) and TP53 (R273H and R175H) were detected by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Correlations between mutations and clinicopathological parameters were analyzed. Results Significant differences were observed in pTNM stage, lymph node metastasis, molecular subtypes, and PR status among the three ethnic groups. The overall mutation rate of PIK3CA and TP53 was 48.95%. The PIK3CA-p.E542K mutation rate in Tibetan cohort was significantly higher than those in Han and Hui cohort, whereas the detection rate of the PIK3CA-p.E545K mutation was lower in Tibetan cohort than that in Han cohort. The PIK3CA-p.E542K mutation was associated with an increased risk of lymph node metastasis. The TP53-p.R175H mutation was significantly correlated with advanced pTNM stage, vascular invasion, and triple-negative breast cancer. The PIK3CA-H1047R and E545K mutations were enriched in the luminal A subtype of breast cancer. Conclusion Considerable ethnic disparities exist in breast cancer mutation profiles in Qinghai, with the high-frequency PIK3CA-p.E542K mutation in Tibetan population potentially serving as a region-specific therapeutic target. Mutations are closely linked to tumor aggressiveness and molecular subtypes, highlighting the value of PIK3CA/TP53 mutation detection for early risk stratification and personalized treatment of breast cancer in high-altitude populations.

Objective To investigate the role of PSMA4 in the prognosis,diagnosis and immune infiltration of lung adenocarcinoma(LUAD),and explore its underlying mechanism.Methods The expression profiles and clinical data of LUAD patients were sourced from the Cancer Genome Atlas(TCGA)database.The expression level of PSMA4 in LUAD tissues(n=539)and normal tissues(n=59)were compared using the Wilcoxon rank-sum test.The expression levels of PSMA4 in LUAD tissues and normal tissues were validated by analyzing the GSE40791 and GSE10072 LUAD datasets obtained from the Gene Expression Omnibus(GEO)database.In addition,tumor and adjacent non-cancerous tissues were collected from 10 LU AD undergoing lung biopsy by fiberoptic bronchoscopy in Second Affiliated Hospital of Army Medical University from January to December 2023.The PSMA4 expression in above samples was further verified using RT-qPCR.RT-qPCR was performed to detect the expression of PSMA4 in lung cancer cells and normal lung epithelial cells.Functional enrichment analysis and immune cell infiltration analysis were conducted on the cells with high and low expression of PSMA4.Cox regression analysis and Kaplan-Meier(KM)survival analysis were used to determine the diagnostic and prognostic value of PSMA4 for LUAD,and a nomogram was constructed to predict the overall survival rate at different time points.Results The analysis of TCGA datasets,GSE40791,and GSE10072 LUAD data revealed that PSMA4 expression was significantly higher in LUAD tissues than in normal tissues(P＜0.01).RT-qPCR further confirmed that the expression of PSMA4 was obviously elevated in LUAD tissues and lung cancer cells than adjacent non-cancerous tissues and normal lung epithelial cells(P＜0.01).High PSMA4 expression could be regarded as a marker for LUAD diagnosis and poor prognosis,and was associated with reduced proportions of Tem cells,TFH cells,B cells,NK cells,Tcm cells,and mast cells in the tumor microenvironment.Conclusion PSMA4 presents significant diagnostic performance for LUAD,and is closely associated with the prognosis and immune infiltration of this malignancy.