Positional expression profiling of the MHC class II and MHC2TA loci. (A) Positional expression profiling map showing relative expression of MHC class II genes and those genes physically located telomeric, within, and centromeric to the MHC class II locus. (B) Positional expression profiling map showing relative expression of MHC2TA and those genes physically located near the MHC2TA locus. For both sections, asterisks indicate cases with CGH data available, and color coding is used to indicate the relative expression of genes. Each row indicates one of the PMBCL cases, by individual patient study number, sorted by average MHC class II expression, from low to high. The last 9 rows are activated B cells (ABC, with hours of activation indicated) and germinal center B cells (GCB). Tot indicates total from a normal lymph node; Cbl, centroblastic; and Ccyte, centrocytes from healthy individuals. MHC class II genes are shown with dots. Gene expression (e) is colored as follows: dark blue, e <-2; medium blue, -2 ≤ e <-1; light blue, -1 ≤ e < 0; yellow, 0 ≤ e < 1; orange, 1 ≤ e < 2; red, e ≥ 2; light gray squares pattern, no value.