Footnotes

• Contributors A-SC performed the DICER1 hotspot sequencing, digital droplet PCR analysis and wrote the manuscript. MA-R performed the DICER1 hotspot sequencing. LdK and BRP edited the manuscript and oversaw some of the laboratory work. WRD provided samples and collected clinical information. DB-DS provided expert pathology opinion. JRP reviewed the diagnostic images, collected clinical information and edited the manuscript. WDF designed the study, wrote and edited the manuscript. All authors read and approved the final manuscript.

• Funding This work was funded by a Canadian Institutes of Health Research Grant to WDF (FDN-148390).

• Competing interests WDF reports grants from Canadian Institutes of Health Research, during the conduct of the study; grants from Astra Zeneca, outside the submitted work.

• Provenance and peer review Not commissioned; externally peer reviewed.

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