TOSO expression in distinct clinically and molecularly defined CLL subgroups. (A) Significantly increased TOSO expression of patients harboring elevated white blood cell (WBC) counts of more than 50 × 10⁹/L (50 000/μL) (P = .02) and unmutated immunoglobulin heavy chain gene with elevated TOSO mRNA (P = .013). (B) Increased TOSO expression in Binet stage C patients (P = .015). (C) MFIR flow cytometric assessment of TOSO surface expression comparing CD38⁻ and CD38⁺ CLL cells of the same patient (n = 19). Box plots in panels A and B show median, 1st and 3rd quartiles, and whiskers (error bars) defined by, at most, 1.5× IQR.