Prognostic factors in 105 Japanese cases of mycosis fungoides and Sézary syndrome: Clusterin expression as a novel prognostic factor

Background The analysis of prognostic factors in Japanese cases of cutaneous T-cell lymphoma (CTCL) is scarce. Clusterin is a ubiquitous 80kDa heterodimeric glycoprotein expressed on tumor cells of systemic and primary cutaneous anaplastic large cell lymphoma. The expression of clusterin in mycosis fungoides (MF) and Sézary syndrome (SS) has only been sporadically reported in a small number of cases. Objective To determine the long-term prognosis of Japanese patients with MF and SS, to identify clinical and pathological factors predictive of survival, and to evaluate the prognostic significance of the International Society for Cutaneous Lymphomas (ISCL) revised staging system (2007). Methods We performed a retrospective cohort study of 105 Japanese patients with MF and SS managed at the Department of Dermatology Asahikawa Medical University from 1976 to 2011. Formalin-fixed, paraffin-embedded sections of MF and SS were immunostained for clusterin, CD30, and Ki-67. Results No statistically significant difference in survival was found between stages IA–IIA and IIIA patients. The significant prognostic factors in the univariate analysis were higher age, TNMB classification, clinical staging, performance status, increased serum LDH level, dermal Ki-67-positive cells, and clusterin expression. In the multivariate analysis, T classification, extracutaneous disease, increased serum LDH level, clusterin expression, and performance status were the significant independent prognostic factors. Conclusion Japanese stage IIIA MF/SS patients contain a subpopulation with a favorable prognosis. The most significant prognostic factor for survival of MF and SS was the presence of extracutaneous disease. Clusterin expression was shown to be a novel unfavorable prognostic factor.