“…14,16 However, TCL-1 expression is well documented in many other neoplasms, including B-cell leukemias and lymphomas and even nonneoplastic cells. 13,16,17 ❚Image 1❚ (Case 53) Peripheral blood smear in T-cell prolymphocytic leukemia with a WBC count >400,000/µL (>400.0 × 10 9 /L) showing striking mature lymphocytosis with variably sized lymphoid cells (Wright, ×75). In T-PLL, TCL-1 oncoprotein dysregulation is due to recurrent chromosomal rearrangements involving the TCL-1 locus at 14q32.1 and TCRαδ at 14q11 or, less commonly, the TCRβ locus at 7q35.…”