ABSTRACT
BACKGROUND: The genetic changes underlying carcinogenesis in patients with risk factors of gallbladder carcinoma (GBC) remains controversial, especially in patients with pancreaticobiliary maljunction (PBM). This study aimed to clarify the association between risk factors of GBC and genetic changes using next-generation sequencing (NGS). METHODS: We retrospectively analyzed resected tissues of 64 patients who were diagnosed with GBC (n = 26), PBM [with GBC (n = 8), without GBC (n = 20)], and chronic cholecystitis, used as a control group (n = 10). DNA was extracted from tumors and their surrounding tissues, which were precisely separated by laser-capture microdissection. Gene alterations of 50 cancer-related genes were detected by NGS and compared with clinical information, including PBM status. RESULTS: The most frequent gene alterations in GBC tissues occurred in TP53 (50%), followed by EGFR (20.6%), RB1 (17.6%), and ERBB2 (17.6%). Gene alterations that were targetable by molecular targeted drugs were detected in 20 cases (58.8%). Statistical analysis of gene alterations and risk factors revealed that TP53 alteration rate was higher in GBC patients with PBM than those without PBM (p = 0.038), and the TP53 mutation rates in the epithelium of control patients, epithelium of PBM patients without GBC, peritumoral mucosa of GBC patients with PBM, and tumor tissue of GBC patients with PBM were 10, 10, 38, and 75%, respectively (p < 0.01). CONCLUSIONS: TP53 alteration more than KRAS mutation was revealed to underlie carcinogenesis in patients with PBM.
Subject(s)
Gallbladder Neoplasms/genetics , Genes, p53/genetics , Mutation , Pancreaticobiliary Maljunction/genetics , Adult , Aged , Case-Control Studies , Cholecystitis/genetics , Female , Gene Expression Profiling , Genes, Retinoblastoma , Genes, erbB-1 , Genes, erbB-2 , Genes, ras , High-Throughput Nucleotide Sequencing , Humans , Male , Middle Aged , Mutation Accumulation , Retrospective Studies , Risk FactorsABSTRACT
BACKGROUND: Pancreaticobiliary maljunction (PBM) is a condition characterized by chronic inflammation due to refluxed pancreatic juice into the biliary tract that is associated with an elevated risk of biliary tract cancer. DNA double-strand breaks (DSBs) are considered the most serious form of DNA damage. DSBs are provoked by inflammatory cell damage and are recognized as an important oncogenic event in several cancers. This study used γ-H2AX, an established marker of DSB formation, to evaluate the impact of DNA damage on carcinogenesis in PBM. METHODS: We investigated γ-H2AX expression immunohistochemically in gallbladder epithelium samples obtained from 71 PBM cases and 19 control cases. RESULTS: Fourteen PBM cases with gallbladder adenocarcinoma were evaluated at non-neoplastic regions. A wide range of nuclear γ-H2AX staining was detected in all PBM and control specimens. γ-H2AX expression was significantly higher in PBM cases versus controls (median γ-H2AX-positive proportion: 14.4 % vs. 4.4 %, p = 0.001). Among the PBM cases, γ-H2AX expression was significantly higher in patients with carcinoma than in those without (median γ-H2AX-positive proportion: 21.4 % vs. 11.0 %, p = 0.031). CONCLUSIONS: DSBs occurred significantly more abundantly in the PBM gallbladder mucosa, especially in the context of cancer, indicating an involvement in PBM-related carcinogenesis.
