B-cell lymphoma development in Rosa26^HGAL mice. (A) Overall survival of Rosa26^HGAL/Sca1-Cre mice, Rosa26^HGAL/Mb1-Cre mice, and Rosa26^HGAL/Aid-Cre mice. All had a significantly shortened lifespan compared with control littermate WT mice. Rosa26^HGAL/Sca1-Cre vs WT, P < .0001; Rosa26^HGAL/Mb1-Cre vs WT, P = .00248; Rosa26^HGAL/Aid1-Cre vs WT, P = .0062; log-rank test). Live animals from all experimental genotypes were censored at 24 months, because they were euthanized at this point based on the experimental design (see"Methods"). (B) B-cell lymphoma–specific survival of Rosa26^HGAL/Sca1-Cre mice, Rosa26^HGAL/Mb1-Cre mice, and Rosa26^HGAL/Aid-Cre mice showing a significantly shortened lifespan for Rosa26^HGAL/Sca1-Cre mice compared with control littermate WT mice (P = .0088, log-rank test). (C) Representative images of large B-cell lymphoma in the spleen from Rosa26^HGAL/Sca1-Cre transgenic mice. Multiple splenic nodules of large pleomorphic cells expressing B220, PAX5 (B-cell marker), HGAL, PNA (GCB marker), and IRF4 (late GC or post-GC marker) but not BCL6 (GCB marker) and CD3 (T-cell marker) (hematoxylin and eosin [HE]; original magnification ×400). (D) B-cell lymphomas were clonal, as confirmed by immunoglobulin heavy chain PCR analysis. PCR analysis of BCR gene rearrangements in infiltrated spleens of diseased Rosa26^HGAL/Sca1-Cre mice and Rosa26^HGAL/Aid-Cre mice. Sorted B cells from the spleens of healthy mice served as a control for polyclonal BCR rearrangements. Lymphoma spleens show an increased clonality within their BCR repertoire (indicated by the code number of each mouse analyzed). Colored boxes denote clonal bands of immunoglobulin genes in different mice.