Genetic alterations identified in WCM271 metastatic lesions; characterization of primary tumor cells. (A and B) Sanger sequencing of TERT promoter performed on DNA from bone metastasis (A) or lung metastasis (B). (C) Copy number alterations in WCM271 are indicated on an ideogram of human chromosomes. Vertical lines represent copy number alterations as indicated in the legend. (D) Primary tumor cells isolated from bone metastasis cultured on mitomycin-treated mouse feeder cells; scale bar = 400 μm. (E) Primary tumor cells cultured on gelatin-coated plates; scale bar = 400 μm. (F) Immunohistochemistry for TTF1 on tumor cells isolated from D; scale bar = 100 μm. (G) Immunohistochemistry for TTF1 on tumor cells isolated from E; scale bar = 100 μm. Immunohistochemistry was performed on 50,000 cells using anti-TTF1 mAB (Neomarkers Thermoscientific, 1:200). TTF1⁺ immunostaining may identify cells of thyroid or lung origin.