SCARB1 and leiomyosarcoma: Leiomyosarcoma. Leiomyosarcoma had the lowest expression of SR-B1 protein, and only 2 of 43 leiomyosarcomas were showed an immunohistochemical score of 1+ (4.70%), no expression of SR-B1 was found in 41/43 (95.34%) cases of leiomyosarcoma.