BiliSeq: A Breakthrough Molecular Test for Bile Duct Cancer

Scientists at UPMC Hillman Cancer Center and the University of Pittsburgh School of Medicine have developed BiliSeq, a molecular test designed to detect bile duct cancer with higher accuracy than standard methods. This test addresses significant challenges in diagnosing bile duct blockages, where it is often difficult to determine if the cause is cancer or a benign condition, leading to potential treatment delays for patients with this rare cancer.

BiliSeq's Performance

A study published in Gastroenterology evaluated BiliSeq's performance over six years, analyzing nearly 3,000 bile duct specimens from over 2,000 patients across the United States. Key findings include:

• BiliSeq detected approximately 82% of bile duct cancers, compared to 44% with pathology alone.
• When combined with pathology, BiliSeq increased cancer detection to nearly 90%.
• The test rarely misclassified benign disease as malignant.

Traditional biopsy and cytology methods often struggle to provide a clear diagnosis because bile duct tumors are frequently small, difficult to access, and surrounded by inflammation or scar tissue.

How BiliSeq Works

BiliSeq detects genetic mutations associated with cancer in bile duct tissue.

This capability allows the test to function effectively even when tumor cells are sparse, damaged, or visually indistinguishable from inflammation under a microscope, which is a common limitation of traditional pathology.

Patient Application and Benefits

BiliSeq is intended for patients with existing bile duct narrowing or obstructions requiring a clearer diagnosis, rather than as a general screening test. Beyond a simple yes-or-no diagnosis, BiliSeq offers significant advantages:

• It identified treatment-relevant genetic information in about one in five patients in the study.
• This information led to changes in patient care management in nearly one-third of those cases.
• BiliSeq results are also being utilized to inform liver transplant decisions for select patients at UPMC.

High-Risk Patient Groups

BiliSeq demonstrated strong detection performance in high-risk patient groups, including those with primary sclerosing cholangitis (PSC) and Hispanic patients. In these populations, pathology alone could miss up to half of cancers; however, combining it with BiliSeq enabled clinicians to identify up to 86% of cancer cases.

This development is part of a broader effort by Pitt and UPMC researchers to create molecular tools for improved cancer diagnosis and treatment. Researchers anticipate BiliSeq will follow a similar path to PancreaSeq, a related molecular test for pancreatic conditions, in becoming widely adopted to enhance patient care.