CTLA4 and neoplasm: CTLA4 expression for the 24 early-onset tumor samples had a bimodal distribution pattern with average log2 expression of 7.2 (8 tumor samples) and 6.3 (16 tumor samples) in the high and low-mode groups, respectively (Fig 2); all five young patients with biochemical recurrence were in the high-mode group (p < 0.002, Fisher’s exact test).