RARA and adenosarcoma: As expected, a comparison between borderline PTs and adenosarcomas revealed intermediate results, with mutations affecting MED12 (100% vs 5%, Fisher's exact test, P = 3.952 × 10−5), TERT promoter (67% vs 0, Fisher's exact test, P = 0.0012), and RARA (67% vs 0, Fisher's exact test, P = 0.0012, Fig. S2C) being significantly more frequent in borderline PTs than in adenosarcomas.