Cell-free DNA from bile outperformed plasma as a potential alternative to tissue biopsy in biliary tract cancer.

BACKGROUND: Biliary tract cancers (BTCs) are rare and highly heterogenous malignant neoplasms. Because obtaining BTC tissues is challenging, the purpose of this study was to explore the potential roles of bile as a liquid biopsy medium in patients with BTC. PATIENTS AND METHODS: Sixty-nine consecutive patients with suspected BTC were prospectively enrolled in this study. Capture-based targeted sequencing was performed on tumor tissues, whole blood cells, plasma, and bile samples using a large panel consisting of 520 cancer-related genes. RESULTS: Of the 28 patients enrolled in this cohort, tumor tissues were available in eight patients, and plasma and bile were available in 28 patients. Somatic mutations were detected in 100% (8/8), 71.4% (20/28), and 53.6% (15/28) of samples comprising tumor tissue DNA, bile cell-free DNA (cfDNA), and plasma cfDNA, respectively. Bile cfDNA showed a significantly higher maximum allele frequency than plasma cfDNA (P = 0.0032). There were 56.2% of somatic single-nucleotide variant (SNVs)/insertions and deletions (indels) shared between bile and plasma cfDNA. When considering the genetic profiles of tumor tissues as the gold standard, the by-variant sensitivity and positive predictive value for SNVs/indels in bile cfDNA positive for somatic mutations were both 95.5%. The overall concordance for SNVs/indels in bile was significantly higher than that in plasma (99.1% versus 78.3%, P < 0.0001). Moreover, the sensitivity of CA 19-9 combined with bile cfDNA achieved 96.4% in BTC diagnosis. CONCLUSION: We demonstrated that bile cfDNA was superior to plasma cfDNA in the detection of tumor-related genomic alterations. Bile cfDNA as a minimally invasive liquid biopsy medium might be a supplemental approach to confirm BTC diagnosis.

MiR-129-2 weakens proliferation and promotes apoptosis of liver cancer cells by suppressing the Wnt signaling pathway.

OBJECTIVE: To explore the effects of micro ribonucleic acid-129-2 (miR-129-2) on proliferation and migration of liver cancer cells and its possible mechanism. PATIENTS AND METHODS: The expression level of miR-129-2 was measured in liver cancer tissues and adjacent tissues from patients with liver cancer. Its level in liver cancer HepG2 cells and normal liver cells L-02 was also detected via quantitative polymerase chain reaction (qPCR). MiR-192-2 overexpression model was established in the HepG2 cell line. The proliferation and apoptosis levels of cells were determined by methyl thiazolyl tetrazolium (MTT) assay and flow cytometry, respectively. Wound healing assay was performed to detect the migration ability of cells. The expressions level of genes in the Wnt signaling pathway were measured through Western blotting. Xenograft tumor model was conducted in nude mice for exploring the in vivo effects of miR-129-2 on liver cancer growth. RESULTS: The expression level of miR-129-2 was significantly lower in liver cancer tissues than that in adjacent tissues (p<0.01), and it was overtly lower in HepG2 cells than that in L-02 cells (p<0.01). Overexpression of miR-129-2 weakened proliferation and migration abilities of liver cancer cells (p<0.01), and evidently increased apoptosis level (p<0.01). Sex-determining region Y-related HMG-box 4 (Sox4) and matrix metalloproteinase-2 (MMP-2) were downregulated, while phosphorylated glycogen synthase kinase-3ß (p-GSK3ß) was upregulated in liver cancer cells overexpressing miR-129-2. Besides, the weight and volume of tumors in nude mice bearing liver cancer were significantly smaller after overexpression of miR-129-2. CONCLUSIONS: MiR-129-2 weakens proliferation and migration and stimulates apoptosis in liver cancer cells mainly by downregulating Sox4 and inactivating the Wnt signaling pathway.