Prognostic significance of gelsolin and MMP12 in Langerhans cell histiocytosis

BACKGROUND Gelsolin and matrix metalloproteinase 12 (MMP12) expression has been reported in Langerhans cell histiocytosis (LCH), but the clinical significance of this expression is unknown. We investigated the associations of these proteins with clinical manifestations in patients diagnosed with LCH. METHODS We performed a retrospective analysis of clinical data from patients diagnosed with LCH and followed up between 1998 and 2008. Available formalin-fixed, paraffin-embedded specimens were used for gelsolin and MMP12 immunohistochemical staining. We analyzed the expression levels of these proteins and their associations with LCH clinical features. RESULTS Specimens from 36 patients (20 males, 16 females) with a diagnosis of LCH based on CD1a positivity with clinical manifestations were available for immunohistochemical staining. Median patient age was 62 months (range, 5 to 207). The expression of gelsolin varied; it was high in 17 patients (47.2%), low in 11 patients (30.6%), and absent in 8 patients (22.2%). The high gelsolin expression group had a higher tendency for multi-organ and risk organ involvement, although the trend was not statistically significant. MMP12 was detected only in 7 patients (19.4%) who showed multi-system involvement (P=0.018) and lower event-free survival (P=0.002) in comparison to patients with negative MMP12 staining. CONCLUSION Gelsolin and MMP12 expression may be associated with the clinical course of LCH, and MMP12 expression may be particularly associated with severe LCH. Further studies of larger populations are needed to define the precise role and significance of gelsolin and MMP12 in the pathogenesis of LCH.