Lifespan of IgH-c-myc transgenic mice. (A) Survival curves of 26 c-myc-KIE_μ, 21 c-myc-KIC_μ, and 42 c-myc-KIC_α mice. Significance was determined with the Gehan-Breslow-Wilcoxon test. (B) Locations of lymphomas in c-myc-KIE_μ, c-myc-KIC_μ, and c-myc-KIC_α mice. Several sites were found in the same mouse. (C) Ki67 index of proliferation of B-cell lymphomas in IgH-c-myc transgenic mice. The Ki67 index was calculated in B-cell lymphomas from 24 c-myc-KIE_μ, 20 c-myc-KIC_μ, and 42 c-myc-KIC_α mice. (D) Clonal origin of B-cell lymphomas of IgH-c-myc transgenic mice. The forward primer was consensus for the V_HJ₅₅₈ family and the reverse primer was 3′ to the J_H4 segment, thus amplifying in theory 4 rearranged bands (V_HJ558D_xJ₁, V_HJ558D_xJ₂, V_HJ558D_xJ₃, and V_HJ558D_xJ₄) of various lengths. The scheme represents a VDJ₁ rearrangement. Amplification with several different genomic DNAs confirmed the clonal status of the B-cell lymphoma. The lack of amplification indicated the use of a V segment different from the V_HJ558 family. The size marker is in the first lane. (E) Sequencing confirmed the clonal status of B-cell lymphoma of IgH-c-myc transgenic mice. Two representative experiments of 5 for wt mice (left) and of 27 for B-cell lymphomas from IgH-c-myc transgenic mice (right) are reported. (F) The V_H segments used for B-cell lymphomas from IgH-c-myc transgenic mice matched with the B-cell repertoire in wt mice (same mice as in panel E).