Cytokine mRNA levels predict PEL class membership. (A) Relative mRNA levels for CCR5, IL-6, and IL-10 as determined by real-time QPCR and expressed as the percentage of HPRT mRNA levels for BC-1 and BCBL-1 cells treated with rapamycin (rapa) or mock-treated; ntc indicates nontemplate control. (B) Summary of rapamycin signaling pathways in PEL (adapted from Science Slides 2005, VisiScience, Chapel Hill, NC). (C) Secreted cytokine levels in picogram per milliliter (log-scale) for virus-negative BJAB and DG75 and KSHV-positive BC-1 and BCBL-1 cell lines. Cytokines are listed on the horizontal axis. (D) Relative levels (vertical axis) of all mRNAs that can be used to predict class membership to PEL of a set of 101 lymphomas (horizontal axis). From this set the relative mRNA for vitamin D receptor (E) and IL-10 (F) levels were mean-centered across n = 101 Affymetrix datasets and averaged for PEL (n = 9), AIDS-associated Burkitt lymphoma (AIDS-BL) (n = 7), AIDS-associated diffuse large B-cell lymphoma (DLBCL) (n = 9), classic, non–AIDS-associated BL (n = 6), non–AIDS-associated DLBCL of immunoblast type (n = 8), non–AIDS-associated DLBCL of centroblast type (n = 23). Histograms show mean and standard deviation. Gray bars indicated 18S RNA levels as control.