The gene expresson profiles of 515 patients with lung adenocarcinoma and 59 paracancerous normal lung tissue met the requirement of this study were obtained from The Cancer Genome Atlas （TCGA） database. According to the median value of the REG1A distribution level， they were divided into high and low expression groups.R 3.6.1 software was employed to analyze the differentially expressed genes between two groups.The Gene Ontology （GO） function annotation was carried out for the differential genes. Meanwhile， GSEA4.1.0 was used for Kyoto Encyclopedia of Genes and Genomes（KEEF） enrichment analysis of the differential genes. Wnt signaling pathway， the signaling pathway that scored the best，was screened， and the mRNA and the protein expression levels of REG1A in the human normal lung epithelial cells （BEAS-2B） and lung adenocarcinoma cells （A549， LC-2， HCC515 and PC14） were tested by real-time fluorescence quantitative PCR（RT-qPCR） and Western blotting methods. The liposome transfection method was used to transfect shREG1A and shNC into the A549 cells， and the A549 cells with REG1A expression knockdown were treated by lithium chloride. The A549 cells were divided into shNC group，shREG1A group，shREG1A+PBS group， and shREG1A+LiCl group.The proliferation activities of the cells in various groups were detected by CCK-8 method.The migration of cells in various groups was detected by Transwell assay.The mRNA and proein expression levels of Wnt-3a，β-catenin，and c-Myc in the cells in various groups were detected with RT-qPCR and Western blotting methods.

The 78 differential genes in low and high expression REG1A groups were screened out， including 50 up-regulated genes and 28 down-regulated genes； these genes were mainly enriched in proton antiporter activity，endoribonuclease activity，maintenance of gastrointestinal epithelium and so on， and the enriched pathways included Wnt signaling pathway，JAK-STAT signaling pathway，and cancer signaling pathway， etc； among which the Wnt signaling pathway had the highest enrichment score. The RT-qPCR and Western blotting results indicated that the expression levels of REG1A mRNA and protein in the lung adenocarcinoma A549，LC-2，HCC515，and PC14 cells were obviously higher than those in human normal lung epithelial cells BEAS-2B（P<0.05）.The REG1A mRNA and protein expression levels in the A549 cells in shREG1A group were obviously decreased compared with shNC group （P<0.05） after REG1A knockdown. There were statistically significant differences in the cell proliferation activities and the number migration cells among shNC group，shREG1A group，shREG1A+PBS group，and shREG1A+LiCl group（P<0.05）；the cell proliferation activities in shREG1A group were significantly lower than those in shNC group and shREG1A+LiCl group（P<0.05），and the number of migration cells in shREG1A group was lower than those in shNC group and shREG1A+LiCl group（P<0.05），but there were no significant differences in the cell proliferation activities and the number of migration cells between shREG1A group and shREG1A+PBS group（P>0.05）.

REG1A is highly expressed in the lung adenocarcinoma cells. It could promote the proliferation and migration of A549 cells through regulating the Wnt/β-catenin signaling pathway. After knockdown REG1A， the proliferation and migration abilities of the A549 cells are significantly inhibited.