EXPRESSION AND CLINICAL SIGNIFICANCE OF LHPP IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Objective: To investigate the expression characteristics, clinical significance and underlying molecular mechanism of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) in esophageal squamous cell carcinoma (ESCC), and to provide novel potential targets for the diagnosis, prognostic evaluation and clinical treatment of ESCC. Methods: The expression difference of LHPP mRNA between ESCC tissues and adjacent normal tissues was analyzed from the Gene Expression Omnibus (GEO) database including GSE20347, GSE38129 and GSE77861. A total of 15 pairs of ESCC tumor tissues and matched adjacent normal tissues, serum samples from 40 newly diagnosed ESCC patients and 20 healthy volunteers were collected. The expression level of LHPP was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Western blot was used to determine the protein expression of LHPP in ESCC cell lines (TE-1, KYSE-30, KYSE-150) and the normal esophageal epithelial cell line Het-1A. The correlation between LHPP expression and survival prognosis of ESCC patients was analyzed based on The Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) between LHPP high and low expression groups were screened, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The characteristics of tumor-infiltrating immune cells, the expression profiles of immune checkpoint genes and the sensitivity to five clinical common chemotherapeutic drugs including paclitaxel were further detected and compared between the two groups. Results: LHPP was significantly down-regulated in ESCC tissues, peripheral serum of ESCC patients and ESCC cell lines (P