A method of predicting survival outcome based on one or more diffuse large B cell lymphoma (DLBCL) samples, which method comprises: a) isolating gene expression products from one or more DLBCL biopsy samples from a subject treated with a therapeutic regimen that includes chemotherapy and Rituximab (R-CHOP); b) obtaining a gene expression profile from the gene expression products, wherein the expression profile comprises an expression level for each of at least 31 of the genes listed in Table 1 for the germinal center B cell gene expression signature and at least 226 of the genes listed in Table 1 for the stromal-1 gene expression signature; c) determining a GCB signature value and a stromal-1 signature value from the gene expression profile, wherein the GCB signature value is an average of the expression levels of the at least 31 genes listed in Table 1 for the GCB gene expression signature and the stromal-1 signature value is an average of the expression levels of the at least 226 genes listed in Table 1 for the stromal-1 gene expression signature; d) calculating a survival predictor score = A - [(x)*(the GCB signature value)] - [(y)*(the stromal-1 signature value)], wherein A is an offset term, (x) is a scale factor between 0.200 and 0.625, and (y) is a scale factor between 0.800 and 1.250, and e) determining the survival outcome for the subject based on the survival predictor score calculated in step d) for any fixed same value of A and for any fixed same values of (x) and (y), wherein a lower survival predictor score indicates a more favorable survival outcome and a higher survival predictor score indicates a less favorable survival outcome for the subject. a) isolating gene expression products from one or more DLBCL biopsy samples from a subject treated with a therapeutic regimen that includes chemotherapy and Rituximab (R-CHOP); b) obtaining a gene expression profile from the gene expression products, wherein the expression profile comprises an expression level for each of at least 31 of the genes listed in Table 1 for the germinal center B cell gene expression signature and at least 226 of the genes listed in Table 1 for the stromal-1 gene expression signature; c) determining a GCB signature value and a stromal-1 signature value from the gene expression profile, wherein the GCB signature value is an average of the expression levels of the at least 31 genes listed in Table 1 for the GCB gene expression signature and the stromal-1 signature value is an average of the expression levels of the at least 226 genes listed in Table 1 for the stromal-1 gene expression signature; d) calculating a survival predictor score = A - [(x)*(the GCB signature value)] - [(y)*(the stromal-1 signature value)], wherein A is an offset term, (x) is a scale factor between 0.200 and 0.625, and (y) is a scale factor between 0.800 and 1.250, and e) determining the survival outcome for the subject based on the survival predictor score calculated in step d) for any fixed same value of A and for any fixed same values of (x) and (y), wherein a lower survival predictor score indicates a more favorable survival outcome and a higher survival predictor score indicates a less favorable survival outcome for the subject.