CIN results from errors in chromosome segregation during mitosis, leading to structural and numerical chromosomal abnormalities. It will generate genomic heterogeneity that acts as a substrate for natural selection. Furthermore, it is proved that tumors with aneuploidies and polyploidy resulting from whole-genome doubling are related to metastasis, treatment resistance, and decreased overall survival. It is estimated that 60%-80% of human tumors exhibit chromosomal abnormalities suggestive of CIN. CIN positively correlates with tumor stage and is enriched in relapsed as well as metastatic tumor specimens. Due to the ubiquity of CIN in cancer cells, it is a potentially non-invasive way to detect CIN in the bile tract exfoliated cells in bile samples for diagnosing and monitoring malignant biliary obstruction patients. UCAD is a new method to detect CIN in the DNA sample from patients, including extracting DNA from bile, analyzing DNA by low-coverage whole-genome sequencing, processing the data by bio-information techniques, and finally optimizing the management of malignant biliary obstruction patients. The investigators intended to conduct a prospective, single-blinded study by analyzing bile samples from malignant biliary obstruction patients and control groups without any tumor in the biliary system or other organs to compare the specificity and sensitivity of the UCAD test for diagnosing malignant biliary obstruction to other modalities, such as bile cytology. The investigators also intend to investigate the potential of UCAD in malignant biliary obstruction patient follow-up by analyzing the CIN level and following malignant biliary obstruction patients for up to 2 years to determine if there is a correlation between CIN level and patient prognosis
Chromosomal instability (CIN) refers to ongoing chromosome segregation errors throughout consecutive cell divisions. CIN is a hallmark of human cancer, and it is associated with poor prognosis, metastasis, and therapeutic resistance. Analyzing CIN of the DNA extracted from bile tract exfoliated cells in bile samples seems a promising method for diagnosing, monitoring, and predicting the prognosis of patients with malignant biliary obstruction, including biliary tract cancer (BTC), pancreatic head carcinoma. CIN can be assessed using experimental techniques such as bulk DNA sequencing, fluorescence in situ hybridization (FISH), or conventional karyotyping. However, these techniques are either time-consuming or non-specific. The investigators here intend to study whether a new method named Ultrasensitive Chromosomal Aneuploidy Detection (UCAD), which is based on low-coverage whole-genome sequencing, can be used to analyze CIN thus helping diagnose malignant biliary obstruction and assessing follow-up.