Identifying a unique chromosomal pattern to predict the gemcitabine response in patients with cholangiocarcinoma

Cholangiocarcinoma (CCA) is an epithelial bile duct cancer frequently found at an advanced stage, leading to poor response to current therapies. Although gemcitabine (GEM) and cisplatin (CIS) are the current gold-standard for treating unresectable CCA, GEM resistance often occurs. To predict the response to GEM, we evaluated chromosomal aberrations using a chromosome microarray, and their association with GEM response by histoculture drug response assay. Our findings revealed principal component analysis and orthogonal partial-least square discriminant analysis cross validated score plot between response and non-response groups were different. Different signature patterns of chromosomes between response and non-response groups analyzed by heatmap analysis identified 34 regions of 15 chromosomes. An increased signal in responders and a decreased signal in non-responders were found in regions 4q32.1, 5q12.3, 10q21.3, 11p11.2, 11q14.2, 16p11.2, 17q22, 21q21.3 and 22q12.3. In contrast, a high signal in non-responders and low signal in responders were seen in regions 2q37.2, 11q14.1, 16q22.3 and 16q23.3. High signal of CDH13 and TENM4 were demonstrated in GEM non-response, while a high CWC27 signal was noted in GEM response. This signature pattern could provide the knowledge to improve a predictive biomarker for GEM response, benefitting for individual CCA patient management and chemotherapeutic selection.