Expression and clinical significance of PIKFYVE gene in hepatocellular carcinoma analyzed based on TCGA database and experimental validation

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Objective: To investigate the expression and clinical significance of human FYVE finger-containing phosphoinositide kinase (PIKFYVE) in hepatocellular carcinoma (HCC) on the basis of cancer genome atlas (The cancer genome atlas, TCGA) database analysis and clinical samples experimental validation. Methods: Based on the data information of 424 clinical samples (including 374 cases of HCC tissues and 50 cases of nontumorous liver tissues) in the TCGA database, Cox regression analysis and Kaplan-Meier method were used to analyse the relationship between the PIKFYVE mRNA expression and the clinical characteristics, prognosis for survival of HCC patients. The relationship between the PIKFYVE gene and immune cell infiltration was examined by correlation analysis between the PIKFYVE gene and 24 immune cells. In addition, we analysed the correlation between the mRNA expression of PIKFYVE gene and RAC-alpha serine/threonine-protein kinase (AKT1), phosphatase and tensin homolog (PTEN), protein kinase C, alpha (PRKCA), inositol polyphosphate-5-phosphatase (INPP5D), phosphoinositide-3-kinase regulatory subunit 1(PIK3R1), Inositol Polyphosphate 4-phosphatase Type II (INPP4B) and phospholipase-C4 gene (PLCB4) in HCC tissues. Meanwhile, paraffin sections of highly differentiated, moderately differentiated, poorly differentiated, and nontumorous liver tissue in the Department of Pathology of the First Affiliated Hospital of Xinjiang Medical University were collected, each of which was 30 cases, and the histopathological observation was carried out by HE staining, and the expression levels of PIKFYVE and Ki67 proteins were verified by immunohistochemistry in each clinical sample. Results: The expression level of PIKFYVE gene in HCC tumours was significantly higher than that in normal liver tissues (P=0.000 2, P<0.01), and the overall survival of patients in the low PIKFYVE expression group was significantly longer than that in the high expression group (HR=1.57, 95%CI: 1.10～2.25, P=0.014). The results of Univariate Cox regression analysis showed that there was an effect of TNM stage, pathological stage, tumour status and residual tumour on Overall survival (OS) (P<0.05), and the expression level of PIKFYVE had an effect on OS survival (P<0.05); the PIKFYVE prognostic risk model score ratio was HR=1.533 (1.077-2.181, P=0.018). Multivariate Cox regression analysis showed a PIKFYVE prognostic risk model score ratio HR=1.481 (0.886-2.476, P=0.134) and an area under the Receiver Operating Characteristic curve of 0.640, which was greater than 0.5, suggesting that the PIKFYVE prognostic risk model has a predictive value in survival prediction. Correlation analysis showed that the expression level of PIKFYVE was highly correlated with immune cell infiltration and TP53 (P<0.01). The immunohistochemistry staining results showed that the expression of PIKFYVE in HCC tissues was significantly higher than that of nontumorous tissues (P<0.05), and there was a negative correlation with the degree of differentiation. Conclusion: PIKFYVE, as an independent risk factor for HCC, is expected to be developed as a clinical diagnostic biomarker for HCC, which will provide a reference for new drugs for the treatment of HCC.