In the univariate analysis, early clinical Binet stage (P = 0.001), asymptomatic disease (P = 0.034), absence of hepatomegaly (P = 0.025) or splenomegaly (P<0.0001), lymphocyte count <20 x 109/L (P = 0.032), low serum of either LDH level (P<0.0001) or β2M (P<0.0001), the presence of an association of 11q deletion and 13q deletion (P = 0.045), and a low number (<40%) of cells with 11q- (P = 0.006) were associated with longer OS (Table C in S1 File). The gene discussed is B2M; the disease is Splenomegaly.