[Expression and clinical significance of Mcl-1 in T-cell non-Hodgkin's lymphoma]

The prognosis of T-cell non-Hodgkin's lymphoma (T-NHL) is poor. Overexpression of myeloid cell leukemia-1 (Mcl-1) gene could inhibit irradiation-and drug-induced apoptosis in several lymphoma cell lines. This study was to detect the expression of Mcl-1 in T-NHL of various subtypes, and explore its correlation to clinicopathologic features and prognosis of T-NHL.

The expression of Mcl-1 protein in 72 specimens of T-NHL was detected by immunohistochemistry. The clinical features, treatments, and outcomes of the T-NHL patients were analyzed retrospectively.

The weak positive rates of Mcl-1 were 44.4% in precursor T lymphoblastic lymphoma (T-LBL), 0% in anaplastic large T-cell lymphoma (ALCL), and 18.9% in other peripheral T-cell lymphoma (PTL); the positive rates were 0%, 100%, and 49.1%, respectively (P<0.001). Weak diffuse cytoplasmic staining of Mcl-1 was detected in T-LBL, and strong cytoplasmic staining with perinuclear accentuation was detected in ALCL. The overall survival time was significantly longer in the PTL patients with high Mcl-1 expression than in the PTL patients with weak/negative Mcl-1 expression (>32 months vs. 15 months, P=0.007), and longer in the T-LBL patients without Mcl-1 expression than in the T-LBL patients with weak Mcl-1 expression (21 months vs. 7 months, P=0.58).

The intensities of Mcl-1 expression in T-NHL of various histological subtypes are different. It is specifically highly expressed in ALCL. High expression of Mcl-1 is correlated to better prognosis of PTL.