Expression and promoter methylation status of leucine rich repeat containing 55 in pancreatic carcinoma tissue and the clinical value / 中华胰腺病杂志

ABSTRACT

Objective:To detect the mRNA expression and methylation status of leucine rich repeat containing 55(LRRC55) gene in pancreatic carcinoma tissues, and discuss the clinical value.Methods:Resected pancreatic ductal adenocarcinoma and normal adjacent specimens from 37 patients admitted in General Surgery of First Affiliated Hospital of Naval Medical University were collected from May 2019 to May 2021. Another two normal pancreas specimens and two blood samples from healthy adults were also collected. All patients′ age, gender, tumor location, tumor size, tumor differentiation, TNM staging, lymphatic metastasis, CEA and CA19-9 level were recorded. Bisulfite treatment of genomic DNA and sequencing analysis was used to study methylation patterns in CpG islands of the promoter for LRRC55 gene in fresh tissues from 2 pancreatic adenocarcinoma and adjacent tissues, 2 normal pancreatic tissues, 2 pancreatic cancer cell lines (PaTu8988 and ASPC1). LRRC55 mRNA in 35 pancreatic adenocarcinoma and adjacent tissues was detected by real-time quantitative PCR and the correlations with clinical parameters were analyzed.Results:CpG islands of LRRC55 in pancreatic adenocarcinoma tissues and pancreatic cancer cell lines was highly methylated and the mean methylation rate was 53% and 71%, respectively; while LRRC55 gene in pancreatic adjacent tissues and normal pancreatic tissues was lowly methylated, and the mean methylation rate was 8% and 11%. The relative expression in the pancreatic adenocarcinoma tissues and the paired adjacent normal tissues was 0.21 (0.02, 1.00 ) and 0.98 (0.33, 3.66 ), respectively; the former was significantly lower than the later and the difference was statistically significant ( P=0.003). Correlation analysis showed that LRRC55 mRNA expression level was related to tumor differentiation and CEA, but not correlated with patients′ age, gender, tumor location and size, CA19-9 level, lymphatic metastasis and TNM staging. Conclusions:Pancreatic cancer tissue and cell lines had abnormal methylation of LRRC55 gene; LRRC55 gene hypermethylation was related with its lower mRNA expression level in pancreatic cancer, which was correlated with the tumor differentiation and CEA level. LRRC55 may be a potential suppressor gene for pancreatic cancer.