Expression of programmed death-1 in cutaneous extranodal natural killer/T-cell lymphoma and its effect on clinical findings and biological behaviour.

ABSTRACT

BACKGROUND: Recent studies have evaluated the expression of programmed death-1 (PD-1) and its prognostic value in malignant T-cell lymphomas. OBJECTIVES: This study investigated whether the positivity of PD-1 was associated with the clinical characteristics of cutaneous extranodal NK/T-cell lymphoma (ENKTL) and evaluated its effects on survival outcomes. METHODS: Forty-one patients with cutaneous ENKTL were included. Clinical features and survival outcomes were analysed according to the positivity of PD-1. RESULTS: There was no significant difference between primary cutaneous ENKTL and secondary cutaneous ENKTL in the expression of PD-1. The degree of disease dissemination was not affected by the positivity of PD-1. Higher positivity for PD-1 was associated with lesions presenting erythematous to purpuric patches that are mainly composed of small tumour cells. Cutaneous ENKTL presenting nodular lesions had a significantly lower number of PD-1-positive infiltrating cells than those with other clinical morphologies. There was no significant effect of PD-1 expression on outcomes such as overall and progression-free survival. LIMITATIONS: This study used a retrospective design and had a small sample size. CONCLUSION: Higher PD-1 positivity is associated with small-cell-predominant cutaneous ENKTL. However, PD-1 expression has no prognostic value in cutaneous ENKTL.