Lihi Atzmony, Lilach Moyal, Meora Feinmesser, Batya Gorovitz, Avraham Hirshberg, Iris Amitay-Laish, Hadas Prag-Naveh, Aviv Barzilai, Emmilia Hodak
DOI: 10.2340/00015555-3578

Recent studies suggest that folliculotropic mycosis fungoides (FMF), the most common variant of mycosis fungoides (MF), presents with 2 distinct clinicopathological stages: early indolent stage and more aggressive advanced/tumour stage. To further characterize these stages, miR-155 expression was studied with qRT-PCR and found to be significantly higher in biopsies of tumour-stage FMF compared with early-stage FMF and inflammatory dermatoses. There was no statistically significant difference in miR-155 expression between early-stage FMF and early-stage MF, nor between tumour-stage FMF and tumour-stage MF. Immunohistochemical analysis revealed a significantly increased number of dermal Ki-67+ proliferating lymphocytes in tumour-stage FMF, together with an increased number of CD20+ B cells and CD68+ macrophages compared with early-stage FMF. Thus, similar to classic MF, miR-155, Ki-67 tumour cell immunoreactivity, and certain tumour-infiltrating inflammatory cells are differentially expressed in early- vs tumour-stage FMF. The results of this study corroborate the notion that FMF presents with 2 distinct stages.

Folliculotropic mycosis fungoides, the most common variant of mycosis fungoides, was recently suggested to present with 2 distinct stages: early-stage and advanced/tumour-stage, each with different prognostic implications. To gain further insight into the different presentations of folliculotropic mycosis fungoides, skin biopsies of folliculotropic mycosis fungoides were studied for miR-155 expression, a well-documented cancer promoter in classic mycosis fungoides, the proliferation marker Ki-67 expression, and the composition of the inflammatory infiltrate. This study shows that, similar to classic mycosis fungoides, expression of miR-155, dermal Ki-67 immunoreactivity, and the number of tumour-infiltrating B-cells and macrophages are also increased in a stage-dependent manner in folliculotropic mycosis fungoides.

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