Multianalyte Test Predicts Drug Resistance in Esophageal Cancer

By LabMedica International staff writers
Posted on 17 Mar 2015

A multianalyte algorithmic immunohistochemistry (IHC) assay accurately identifies patients with locoregional esophageal adenocarcinoma (EC) who exhibit extreme resistance to neoadjuvant chemoradiotherapy.

The test analyzes the localization of three protein biomarkers within a patient's tumor to classify the cancer as either responsive to or resistant to presurgical chemoradiotherapy and demonstrates strong accuracy and specificity in identifying patients with tumors that are unlikely to respond to standard presurgical (neoadjuvant) chemotherapy and radiation.

Image: Histopathology of esophageal carcinoma showing infiltrating nests of neoplastic cells (Photo courtesy of Dr. Elliot Weisenberg, MD).

Scientists at Baylor College of Medicine (Houston TX, USA) and their colleagues studied archived biopsy specimens of EC which were subject to IHC examination of compartmentalized immunoreactivity of nuclear factor kappa B (NF-κB), Sonic Hedgehog (SHH), and GLI family zinc finger 1 (Gli-1), and a labeling index score was assigned to each biomarker. Pretreatment tumor biopsies were used to evaluate resistance (exCTRT) or responsiveness to (non-exCTRT) standard presurgical chemoradiotherapy (CTRT) regimens under accredited certified laboratory protocols.

According to validation studies, the DecisionDx-EC test (Castle Biosciences, Inc.; Friendswood, TX, USA) can reliably differentiate patients who are complete or partial responders to chemoradiotherapy from those who are non-responders. An initial, single center clinical validation study of 167 patients, which was used as training set for the current validation study, achieved an area under the curve (AUC) of 0.96 and an overall accuracy of 90%. The second validation, enrolled 64 patients from two independent institutions, and achieved an AUC of 0.96 and an overall accuracy of 84% for classifying which patients are likely to be highly resistant to presurgical chemotherapy treatment for esophageal cancer.

Derek Maetzold, BS, MBA, the President and CEO of Castle Biosciences, said, “Publication of these results is a culmination of our extensive program to analytically and clinically validate a new predictive test for esophageal cancer. DecisionDx-EC fits well within our strategy of developing and commercializing valuable prognostic tests that help physicians to select the most appropriate care for their patients.” The study was published on February 19, 2015, in the journal Gastrointestinal Cancer: Targets and Therapy.

Related Links:
Baylor College of Medicine
Castle Biosciences, Inc.