ALK and angioimmunoblastic T-cell lymphoma: A defect in T-cell receptor (TCR) αβ protein expression (based on immunohistochemical detection using the antibody βF-1) has been identified in > 90% of ALK+ and ALK– anaplastic large-cell lymphomas142 compared with loss of βF-1 expression in only approximately 10% of peripheral T-cell lymphoma unspecified and no angioimmunoblastic T-cell lymphomas (AILT).