CT7 and MAGE-A3/6 immunostaining correlates with elevated plasma-cell proliferation in multiple myeloma. (A) CT7-33 IHC scoring for MGUS and multiple myeloma specimens was plotted against PCPI and the median values were compared. Both the ++ and ++++ categories were associated with elevated PCPI compared with CT7-negative specimens, with respective P values of .02 and .04 by 2-tailed t test. (B) M3H67 IHC was similarly analyzed and IHC scoring of +++ and ++++ was associated with elevated PCPI compared with MAGE-A–negative samples (P = .004 and .009, respectively). ▪ indicates IHC-negative specimens; ▴, focal or +, less than 25% of cells IHC positive; ▾, ++, 25% to 50%; ♦, +++, 50% to 75%; and •, +++, greater than 75%. P values are relative to the neg group in each group.