An analysis of genomic rearrangements detected by a diagnostic lineage test helped determine whether multiple non–small cell lung cancer tumors were independent primary tumors or sites of metastatic disease, according to study results.
“Unfortunately, distinguishing between independent primary tumors and metastasis is a frequent dilemma for pathologists,” researcher Marie-Christine Aubry, MD, a pathologist at Mayo Clinic in Rochester, Minn., said in a press release. “We need better tests to help the clinician match the treatment approach to the patient’s individual needs.”
Aubry and colleagues evaluated data from 41 NSCLC tumor samples, which included 33 adenocarcinoma samples and eight squamous cell carcinoma samples. Researchers conducted mate-pair next generation sequencing to identify chromosomal breakpoints in each of the samples.
Overall, sequencing identified 2,201 unique rearrangements in the samples. The mean number of breakpoints in one tumor was 54 (range, 3-276).
Researchers found no shared somatic genomic rearrangements when they compared genomic data between samples of different histopathologically confirmed independently primary tumors. However, shared breakpoints were detected in 8% to 75% of samples from individual primary tumor or metastasis pairs.
To confirm the accuracy of the diagnostic lineage test, researchers then compared genomic data with pathologists’ review of 11 sample pairs. The pathologists and genomic data were in concordance for eight out of nine sample pairs. The remaining two pairs were indeterminate.
“It is not definitive in terms of a test that we can roll out to clinical practice tomorrow, but it does show proof of principle,” researcher Dennis Wigle, MD, PhD, a thoracic surgeon at Mayo Clinic, said in the press release. “We need to expand this study to analyze more tumor samples and get more data on the sensitivity and specificity of this test. Then we will need to explore how we can make this test a part of standard diagnostic testing and finally assess how it will impact clinical care. Hopefully this test will provide an inroad for clinicians faced with scenarios where they don’t know what course of action is best for their patients.”
Disclosure: The researchers report research funding from, honoraria from and royalties on patents licensed to Abbott Molecular, Oncospire, Pfizer and Qiagen.