New research suggests that genetic testing can help distinguish mesothelioma from non-small cell lung cancer, a disease with similar symptoms but very different treatment needs.

A Canadian research team noted that two sets of proteins — sex-determining region Y box 6 (SOX6) and disabled homolog 2 (DAB2) — have previously been suggested as potential diagnostic markers for mesothelioma, so they decided to test this idea.

The group — which includes researchers from Vancouver General Hospital’s Department of Pathology, the University of British Columbia’s Department of Pathology and the British Columbia Cancer Agency — published their findings March 29 in the American Journal of Surgical Pathology.

Testing the Night Away

Using 184 tissue samples, the team conducted immunostaining tests to see if they could distinguish 40 epithelioid and 23 sarcomatoid mesothelioma samples from 52 adenocarcinoma tissue samples, 57 squamous cell carcinoma samples and 12 large cell carcinoma samples.

The team was able to correctly identify epithelioid mesothelioma cells 85 percent of the time with SOX6 testing and 98 percent of the time with DAB2 tests. Their testing fared worse for sarcomatoid mesothelioma, with SOX6 getting it right only 13 percent of the time, while the DAB2 testing results couldn’t be quantified due to background stromal staining.

Additionally, SOX6 was able to correctly distinguish mesothelioma cells from adenocarcinoma 94 percent of the time, from squamous cell carcinoma 79 percent of the time and from large cell carcinoma 92 percent of the time. DAB2 tests were less accurate overall, with researchers distinguishing mesothelioma from adenocarcinoma 77 percent of the time, from squamous cell carcinoma 86 percent of the time and from large cell carcinoma 67 percent of the time.

Better When Combined

SOX6 immunostaining posted even better results when tested alongside other mesothelioma markers — including calretinin, WT1, D2-40, CK5/6, HEG1 — enabling researchers to correctly identify the mesothelioma cells 95 percent of the time or more.

Based on these findings, the researchers concluded that “SOX6 is a promising marker for the diagnosis of mesothelioma and potentially could be combined with other mesothelial markers or a broad-spectrum carcinoma marker to reach an accurate diagnosis with relatively few immunostains.”

By contrast, they felt that DAB2 staining had limited diagnostic use, owing to its relatively low accuracy and the difficulty they had interpreting the immunostaining results.

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